Adding metadata

26 files changed, 4924 insertions, 0 deletions

diff --git a/dev-cpp/eigen/Manifest b/dev-cpp/eigen/Manifest
new file mode 100644
index 000000000000..e78035ce5e3c
--- /dev/null
+++ b/dev-cpp/eigen/Manifest
@@ -0,0 +1,6 @@
+DIST eigen-3.4.0.tar.bz2 2143091 BLAKE2B a32aac13cbab68cfaaa252d8a406e6a36ecfd1239361412b1f9baa08284a94467479c08ffae10cb847e9916472b46b1c1af4efbf81f957c8200a4379acd42c42 SHA512 cc488eb111e0e248744d2bc4475b345b5fb82361dff226a5b73a33bd0388de8c219cff8cffcf8f476b672fc0e223f339e8c6a1cfb6293840a4a6abf232438a89
+DIST eigen-3.4.1.tar.bz2 2157363 BLAKE2B 382fcebd716d81019c4606974f8db22234ff34c415d465eb5cf9dbab34d4fa9bca7a3ae6ef64a7eca627cdbacb35fdac862005b0a14ec2d851831246f879f374 SHA512 806be7536f811eb77898a9431eac4fe446fbdd41c2a33ebe30e56750920c105e24bc41d8cbb4a5c01ee770ded9c58f06ff37058d17c6e2301bc9021a864bb549
+DIST eigen-3.4.1_p1.patch 1007 BLAKE2B 0a2af4c2cd8fc423535e046919fe7f931e9b718df1ff799ccc451139c084a344988fc8d1277fd1970827051ce1fcae5512222310fea00a9f1a654f3b1cffbec8 SHA512 ec3f6c78c19544f9a4f2c52e069b573eb633d67998acdd7d74e9769102ec9dfdbf68fca1492002ed0ec6b3e9a25637afa9978cfb80dd3e3f9aa0e1a34ac64534
+DIST eigen-3.4.1_p2.patch 1054 BLAKE2B b46683962764a9dd560932e2230177f91e56d9e4b48ce7de79cad5743b59050aafde4f2da1db961adfb5228ac17f477e598cdf23c4150fa254d2640e4fff3a6d SHA512 bdcd4599ccb88f0599aa74fd5a73135dcc5bb9ad0bc2791517473a48f938bb784e62376e829b8b5b3d6f5149bc8874bf77655c1bfe63f86afbc151c2c86d6732
+DIST eigen-5.0.1.tar.bz2 2335713 BLAKE2B a7ccf9fc63b25b0e5ad8940ccf541cf4977a80ded671757ae1965cd0ca480fd11361de8eaf18cae94a74cde68979a76f5a18b47b696cdd6939b6cf30922e5fd4 SHA512 5cb11c7f1945ae7f36c5deb067b8d5a962d2d3cff7d4dbec8a4ee255ee6aae1b7dbe6d5a6dcc6fe77554ef191e4101366bf79cfb34f5cf06a0e4de311afbeaf6
+DIST eigen-lapack_addons-3.4.1.tgz 6215074 BLAKE2B 564c3398de1f4ea249b58957a482cda0b5eb99e5021e1f18abf3b4d2893fed48912bfa8386681fcae03dd933eea91644f7429d47a53684d64462209a6ae76f30 SHA512 5a827d0befb521cb430f0d63f5000e7955359bc637cdb7292d942712e98c0702570a5b650a72fc609bf5b43633661c0e51de7761ae892df6ff0aab667f436edf
diff --git a/dev-cpp/eigen/eigen-3.4.0-r3.ebuild b/dev-cpp/eigen/eigen-3.4.0-r3.ebuild
new file mode 100644
index 000000000000..21f9174b1ab0
--- /dev/null
+++ b/dev-cpp/eigen/eigen-3.4.0-r3.ebuild
@@ -0,0 +1,458 @@
+# Copyright 1999-2026 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+FORTRAN_NEEDED="test"
+inherit cmake cuda fortran-2 llvm toolchain-funcs
+
+DESCRIPTION="C++ template library for linear algebra"
+HOMEPAGE="https://eigen.tuxfamily.org/index.php?title=Main_Page"
+
+if [[ ${PV} = *9999* ]] ; then
+	inherit git-r3
+	EGIT_REPO_URI="https://gitlab.com/lib${PN}/${PN}.git"
+	if [[ ${PV} = 3.4.9999* ]] ; then
+		EGIT_BRANCH="3.4"
+	fi
+else
+	SRC_URI="
+		https://gitlab.com/lib${PN}/${PN}/-/archive/${PV}/${P}.tar.bz2
+		test? ( lapack? ( https://downloads.tuxfamily.org/${PN}/lapack_addons_3.4.1.tgz -> ${PN}-lapack_addons-3.4.1.tgz ) )
+	"
+	KEYWORDS="~alpha amd64 arm arm64 ~hppa ~loong ~mips ppc ppc64 ~riscv ~s390 ~sparc x86 ~arm64-macos ~x64-macos"
+fi
+
+LICENSE="MPL-2.0"
+SLOT="3"
+
+# The following lines are shamelessly stolen from ffmpeg-9999.ebuild with modifications
+ARM_CPU_FEATURES=(
+	neon:NEON
+)
+PPC_CPU_FEATURES=(
+	altivec:ALTIVEC
+	vsx:VSX
+)
+X86_CPU_FEATURES=(
+	avx:AVX
+	avx2:AVX2
+	avx512f:AVX512
+	avx512dq:AVX512DQ
+	f16c:FP16C
+	fma3:FMA
+	popcnt:POPCNT
+	sse:SSE
+	sse2:SSE2
+	sse3:SSE3
+	ssse3:SSSE3
+	sse4_1:SSE4_1
+	sse4_2:SSE4_2
+)
+# MIPS_CPU_FEATURES=(
+# 	msa:MSA
+# )
+# S390_CPU_FEATURES=(
+# 	z13:Z13
+# 	z14:Z14
+# )
+
+CPU_FEATURES_MAP=(
+	"${ARM_CPU_FEATURES[@]/#/cpu_flags_arm_}"
+	"${PPC_CPU_FEATURES[@]/#/cpu_flags_ppc_}"
+	"${X86_CPU_FEATURES[@]/#/cpu_flags_x86_}"
+	# "${MIPS_CPU_FEATURES[@]/#/cpu_flags_mips_}"
+	# "${S390_CPU_FEATURES[@]/#/cpu_flags_s390_}"
+)
+
+IUSE_TEST_BACKENDS=(
+	"adolc"
+	"boost"
+	"cholmod"
+	"fftw"
+	"klu"
+	"opengl"
+	"openmp"
+	"pastix"
+	"sparsehash"
+	"spqr"
+	"superlu"
+	"umfpack"
+)
+
+IUSE="${CPU_FEATURES_MAP[*]%:*} clang cuda hip debug doc lapack mathjax test ${IUSE_TEST_BACKENDS[*]}" #zvector
+
+REQUIRED_USE="
+	test? ( !lapack )
+	|| ( ${IUSE_TEST_BACKENDS[*]} )
+"
+
+# Tests failing again because of compiler issues; bugs #932646, #943401
+RESTRICT="test !test? ( test )"
+
+BDEPEND="
+	doc? (
+		app-text/doxygen[dot]
+		dev-texlive/texlive-bibtexextra
+		dev-texlive/texlive-fontsextra
+		dev-texlive/texlive-fontutils
+		dev-texlive/texlive-latex
+		dev-texlive/texlive-latexextra
+		mathjax? ( dev-libs/mathjax )
+	)
+	test? ( virtual/pkgconfig )
+"
+
+# METIS
+# MPREAL
+# dev-libs/mpfr:0
+# dev-libs/gmp:0
+
+TEST_BACKENDS="
+		boost? ( dev-libs/boost )
+		adolc? ( sci-libs/adolc[sparse] )
+		cholmod? ( sci-libs/cholmod:= )
+		fftw? ( sci-libs/fftw )
+		spqr? ( sci-libs/spqr )
+		klu? ( sci-libs/klu )
+		opengl? (
+			media-libs/freeglut
+			media-libs/glew
+			media-libs/libglvnd
+		)
+		pastix? ( sci-libs/pastix[-mpi] )
+		sparsehash? (
+			amd64? ( dev-cpp/sparsehash )
+			arm64? ( dev-cpp/sparsehash )
+			ppc64? ( dev-cpp/sparsehash )
+			x86?   ( dev-cpp/sparsehash )
+		)
+		superlu? ( sci-libs/superlu )
+		umfpack? ( sci-libs/umfpack )
+"
+DEPEND="
+	test? (
+		cuda? (
+			!clang? (
+				dev-util/nvidia-cuda-toolkit
+			)
+			clang? (
+				llvm-core/clang[llvm_targets_NVPTX]
+				openmp? ( llvm-runtimes/openmp[llvm_targets_NVPTX,offload] )
+			)
+		)
+		hip? ( dev-util/hip )
+		lapack? ( virtual/lapacke )
+		${TEST_BACKENDS}
+	)
+"
+
+PATCHES=(
+	"${FILESDIR}/${PN}-3.3.9-max-macro.patch"
+	"${FILESDIR}/${PN}-3.4.0-doc-nocompress.patch" # bug 830064
+	"${FILESDIR}/${PN}-3.4.0-buildstring.patch"
+	"${FILESDIR}/${PN}-3.4.0-noansi.patch"
+	"${FILESDIR}/${PN}-3.4.0-cxxstandard.patch"
+	"${FILESDIR}/${PN}-3.4.0-ppc-no-vsx.patch" # bug 936107
+)
+
+# TODO should be in cuda.eclass
+cuda_set_CUDAHOSTCXX() {
+	local compiler
+	tc-is-gcc && compiler="gcc"
+	tc-is-clang && compiler="clang"
+	[[ -z "$compiler" ]] && die "no compiler specified"
+
+	local package="sys-devel/${compiler}"
+	local version="${package}"
+	local CUDAHOSTCXX_test
+	while
+		CUDAHOSTCXX="${CUDAHOSTCXX_test}"
+		version=$(best_version "${version}")
+		if [[ -z "${version}" ]]; then
+			if [[ -z "${CUDAHOSTCXX}" ]]; then
+				die "could not find supported version of ${package}"
+			fi
+			break
+		fi
+		CUDAHOSTCXX_test="$(
+			dirname "$(
+				realpath "$(
+					which "${compiler}-$(echo "${version}" | grep -oP "(?<=${package}-)[0-9]*")"
+				)"
+			)"
+		)"
+		version="<${version}"
+	do ! echo "int main(){}" | nvcc "-ccbin ${CUDAHOSTCXX_test}" - -x cu &>/dev/null; done
+
+	export CUDAHOSTCXX
+}
+
+pkg_setup() {
+	use test && use cuda && use clang && llvm_pkg_setup
+}
+
+src_unpack() {
+	if [[ ${PV} = *9999* ]] ; then
+		git-r3_src_unpack
+	else
+		unpack "${P}.tar.bz2"
+
+		if use test && use lapack; then
+			cd "${S}/lapack" || die
+			unpack "${PN}-lapack_addons-3.4.1.tgz"
+		fi
+	fi
+}
+
+src_prepare() {
+	cmake_src_prepare
+
+	sed \
+		-e "/add_subdirectory(bench\/spbench/s/^/#DONOTCOMPILE /g" \
+		-e "/add_subdirectory(demos/s/^/#DONOTCOMPILE /g" \
+		-i CMakeLists.txt || die
+
+	if ! use test; then
+		sed \
+			-e "/add_subdirectory(test/s/^/#DONOTCOMPILE /g" \
+			-e "/add_subdirectory(scripts/s/^/#DONOTCOMPILE /g" \
+			-e "/add_subdirectory(failtest/s/^/#DONOTCOMPILE /g" \
+			-e "/add_subdirectory(blas/s/^/#DONOTCOMPILE /g" \
+			-e "/add_subdirectory(lapack/s/^/#DONOTCOMPILE /g" \
+			-i CMakeLists.txt || die
+	fi
+}
+
+src_configure() {
+	local mycmakeargs=(
+		-DBUILD_SHARED_LIBS="yes"
+		-DBUILD_TESTING="$(usex test)"
+
+		-DEIGEN_BUILD_DOC="$(usex doc)" # Enable creation of Eigen documentation
+		-DEIGEN_BUILD_PKGCONFIG="yes" # Build pkg-config .pc file for Eigen
+	)
+	if use doc || use test; then
+		mycmakeargs+=(
+			# needs Qt4
+			-DEIGEN_TEST_NOQT="yes" # Disable Qt support in unit tests
+		)
+	fi
+
+	if use doc; then
+		mycmakeargs+=(
+			-DEIGEN_DOC_USE_MATHJAX="$(usex mathjax)" # Use MathJax for rendering math in HTML docs
+			-DEIGEN_INTERNAL_DOCUMENTATION=no # Build internal documentation
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			# the OpenGL testsuite is extremely brittle, bug #712808
+			-DOpenGL_GL_PREFERENCE="GLVND"
+			-DEIGEN_TEST_OPENGL="$(usex opengl)" # Enable OpenGL support in unit tests
+			-DEIGEN_TEST_OPENMP="$(usex openmp)" # Enable/Disable OpenMP in tests/examples
+
+			-DCMAKE_DISABLE_FIND_PACKAGE_MPREAL=ON
+
+			-DEIGEN_TEST_CXX11=yes
+
+			# -DEIGEN_TEST_CUSTOM_CXX_FLAGS= # Additional compiler flags when compiling unit tests.
+			# -DEIGEN_TEST_CUSTOM_LINKER_FLAGS= # Additional linker flags when linking unit tests.
+			# -DEIGEN_TEST_BUILD_FLAGS= # Options passed to the build command of unit tests
+
+			# -DEIGEN_BUILD_BTL=yes # Build benchmark suite
+
+			-DEIGEN_TEST_BUILD_DOCUMENTATION="$(usex doc)" # Test building the doxygen documentation
+
+			# -DEIGEN_COVERAGE_TESTING=no # Enable/disable gcov
+			# -DEIGEN_CTEST_ERROR_EXCEPTION= # Regular expression for build error messages to be filtered out
+			# -DEIGEN_DEBUG_ASSERTS=no # Enable advanced debugging of assertions
+			# -DEIGEN_NO_ASSERTION_CHECKING=no # Disable checking of assertions using exceptions
+			# -DEIGEN_TEST_NO_EXCEPTIONS=no # Disables C++ exceptions
+			# -DEIGEN_TEST_NO_EXPLICIT_ALIGNMENT=no # Disable explicit alignment (hence vectorization) in tests/examples
+			# -DEIGEN_TEST_NO_EXPLICIT_VECTORIZATION=no # Disable explicit vectorization in tests/examples
+
+			# -DEIGEN_DASHBOARD_BUILD_TARGET=buildtests # Target to be built in dashboard mode, default is buildtests
+
+			# -DEIGEN_DEFAULT_TO_ROW_MAJOR=no # Use row-major as default matrix storage order
+
+			# -DEIGEN_TEST_MATRIX_DIR=yes # Enable testing of realword sparse matrices contained in the specified path
+			# -DEIGEN_TEST_MAX_SIZE=320 # Maximal matrix/vector size, default is 320
+			# -DEIGEN_SPLIT_LARGE_TESTS=no # Split large tests into smaller executables
+		)
+
+		use !adolc      && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_Adolc="TRUE" )
+		use !boost      && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_Boost="TRUE" )
+		use !cholmod    && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_CHOLMOD="TRUE" )
+		use !fftw       && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_FFTW="TRUE" )
+		use !sparsehash && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_GoogleHash="TRUE" )
+		use !klu        && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_KLU="TRUE" )
+		use !opengl     && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_OpenGL="TRUE" )
+		use !openmp     && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_OpenMP="TRUE" )
+		use !pastix     && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_PASTIX="TRUE" )
+		use !spqr       && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_SPQR="TRUE" )
+		use !superlu    && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_SuperLU="TRUE" )
+		use !umfpack    && mycmakeargs+=( -DCMAKE_DISABLE_FIND_PACKAGE_UMFPACK="TRUE" )
+
+		if use lapack; then
+			mycmakeargs+=(
+				-DEIGEN_ENABLE_LAPACK_TESTS=yes
+				-DEIGEN_TEST_EXTERNAL_BLAS=yes # Use external BLAS library for testsuite
+				-DCMAKE_DISABLE_FIND_PACKAGE_SuperLU=ON
+			)
+		fi
+
+		if use arm; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use arm64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON64="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use ppc || use ppc64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_ALTIVEC="$(usex cpu_flags_ppc_altivec)"
+				-DEIGEN_TEST_VSX="$(usex cpu_flags_ppc_vsx)"
+			)
+		fi
+
+		if use amd64 || use x86; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_32BIT=no # Force generating 32bit code.
+				# -DEIGEN_TEST_X87=no # Force using X87 instructions. Implies no vectorization.
+				-DEIGEN_TEST_SSE2="$(usex cpu_flags_x86_sse2)"
+				-DEIGEN_TEST_SSE3="$(usex cpu_flags_x86_sse3)"
+				-DEIGEN_TEST_SSSE3="$(usex cpu_flags_x86_ssse3)"
+				-DEIGEN_TEST_FMA="$(usex cpu_flags_x86_fma3)"
+				-DEIGEN_TEST_SSE4_1="$(usex cpu_flags_x86_sse4_1)"
+				-DEIGEN_TEST_SSE4_2="$(usex cpu_flags_x86_sse4_2)"
+				-DEIGEN_TEST_AVX="$(usex cpu_flags_x86_avx)"
+				-DEIGEN_TEST_F16C="$(usex cpu_flags_x86_f16c)"
+				-DEIGEN_TEST_AVX2="$(usex cpu_flags_x86_avx2)"
+				-DEIGEN_TEST_AVX512="$(usex cpu_flags_x86_avx512f)"
+				-DEIGEN_TEST_AVX512DQ="$(usex cpu_flags_x86_avx512dq)"
+			)
+		fi
+
+		if use mips; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_MSA=no # Enable/Disable MSA in tests/examples
+			)
+		fi
+
+		if use s390; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_Z13=no # Enable/Disable S390X(zEC13) ZVECTOR in tests/examples
+				# -DEIGEN_TEST_Z14=no # Enable/Disable S390X(zEC14) ZVECTOR in tests/examples
+			)
+		fi
+
+		mycmakeargs+=(
+			-DEIGEN_TEST_CUDA="$(usex cuda)" # Enable CUDA support in unit tests
+			-DEIGEN_TEST_CUDA_CLANG="$(usex cuda "$(usex clang)")" # Use clang instead of nvcc to compile the CUDA tests
+
+			-DEIGEN_TEST_HIP="$(usex hip)" # Add HIP support.
+
+			# -DEIGEN_TEST_SYCL=no # Add Sycl support.
+			# -DEIGEN_SYCL_TRISYCL=no # Use the triSYCL Sycl implementation (ComputeCPP by default).
+		)
+
+		if use cuda; then
+			cuda_add_sandbox -w
+			if use clang; then
+				local llvm_prefix
+				llvm_prefix="$(get_llvm_prefix -b)"
+				export CC="${llvm_prefix}/bin/clang"
+				export CXX="${llvm_prefix}/bin/clang++"
+				export LIBRARY_PATH="${ESYSROOT}/usr/$(get_libdir)"
+			else
+				cuda_set_CUDAHOSTCXX
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CUDAHOSTCXX}"
+				)
+			fi
+			if [[ "${CUDA_VERBOSE}" == true ]]; then
+				mycmakeargs+=(
+					-DCUDA_VERBOSE_BUILD=yes
+				)
+				NVCCFLAGS+=" -v"
+			fi
+
+			export CUDAFLAGS="${NVCCFLAGS}"
+
+			[[ -z "${CUDAARCHS}" ]] && einfo "trying to determine host CUDAARCHS"
+			: "${CUDAARCHS:=$(__nvcc_device_query)}"
+			export CUDAARCHS
+
+			mycmakeargs+=(
+				-DEIGEN_CUDA_COMPUTE_ARCH="${CUDAARCHS}"
+			)
+		fi
+	fi
+
+	cmake_src_configure
+}
+
+src_compile() {
+	local targets=()
+	if use doc; then
+		targets+=( doc )
+		HTML_DOCS=( "${BUILD_DIR}"/doc/html/. )
+	fi
+	if use test; then
+		targets+=( buildtests )
+		if ! use lapack; then
+			targets+=( blas )
+		fi
+		# tests generate random data, which
+		# obviously fails for some seeds
+		export EIGEN_SEED=712808
+	fi
+
+	if use doc || use test; then
+		cmake_src_compile "${targets[@]}"
+	fi
+}
+
+src_test() {
+	CMAKE_SKIP_TESTS=(
+		product_small_32           #  143 (Subprocess aborted)
+		product_small_33           #  144 (Subprocess aborted)
+
+		eigensolver_selfadjoint_13 #  452 (Subprocess aborted)
+
+		cholmod_support_21         #  726 (Subprocess aborted)
+		cholmod_support_22         #  727 (Subprocess aborted)
+
+		NonLinearOptimization      #  930 (Subprocess aborted)
+		openglsupport              #  990 (Failed)
+		levenberg_marquardt        # 1020 (Subprocess aborted)
+	)
+
+	if use cuda ; then
+		cuda_add_sandbox -w
+
+		CMAKE_SKIP_TESTS+=(
+			cxx11_tensor_cast_float16_gpu
+			cxx11_tensor_gpu_5
+		)
+	fi
+
+	if use lapack ; then
+		CMAKE_SKIP_TESTS+=(
+			"^LAPACK-.*$"
+		)
+	fi
+
+	local myctestargs=(
+		-j1 # otherwise breaks due to cmake reruns
+	)
+
+	cmake_src_test
+}
diff --git a/dev-cpp/eigen/eigen-3.4.1.ebuild b/dev-cpp/eigen/eigen-3.4.1.ebuild
new file mode 100644
index 000000000000..65f1b42f809f
--- /dev/null
+++ b/dev-cpp/eigen/eigen-3.4.1.ebuild
@@ -0,0 +1,651 @@
+# Copyright 1999-2026 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+LLVM_COMPAT=( {21..23} )
+LLVM_OPTIONAL="cuda-clang"
+
+PYTHON_COMPAT=( python3_{13..14} )
+
+FORTRAN_NEEDED="no"
+
+LAPACK_ADDONS_PV="3.4.1"
+
+inherit cmake cuda flag-o-matic fortran-2 llvm-r2 python-any-r1 toolchain-funcs virtualx
+
+DESCRIPTION="C++ template library for linear algebra"
+HOMEPAGE="https://eigen.tuxfamily.org/index.php?title=Main_Page"
+
+if [[ ${PV} = *9999* ]] ; then
+	inherit git-r3
+	EGIT_REPO_URI="https://gitlab.com/lib${PN}/${PN}.git"
+	if [[ ${PV} = *.9999* ]] ; then
+		EGIT_BRANCH="$(ver_cut 1-2)"
+	fi
+else
+	# we backport two patches from the 3.4 branch
+	SRC_URI="
+		https://gitlab.com/lib${PN}/${PN}/-/archive/${PV}/${P}.tar.bz2
+		https://gitlab.com/libeigen/eigen/-/commit/0295f81a835ef69e2bacd9e75ab5782eca398720.patch -> ${P}_p1.patch
+		https://gitlab.com/libeigen/eigen/-/commit/28ded8800c26864e537852658428ab44c8399e87.patch -> ${P}_p2.patch
+	"
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~arm64-macos ~x64-macos"
+fi
+
+SRC_URI+="
+	test? (
+		lapack? (
+			https://downloads.tuxfamily.org/${PN}/lapack_addons_${LAPACK_ADDONS_PV}.tgz
+				-> ${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz
+		)
+	)
+"
+
+LICENSE="MPL-2.0"
+SLOT="3/$(ver_cut 1-2)"
+
+# The following lines are shamelessly stolen from ffmpeg-9999.ebuild with modifications
+ARM_CPU_FEATURES=(
+	neon:NEON
+)
+PPC_CPU_FEATURES=(
+	altivec:ALTIVEC
+	vsx:VSX
+)
+X86_CPU_FEATURES=(
+	avx:AVX
+	avx2:AVX2
+	avx512f:AVX512
+	avx512dq:AVX512DQ
+	f16c:FP16C
+	fma3:FMA
+	popcnt:POPCNT
+	sse:SSE
+	sse2:SSE2
+	sse3:SSE3
+	ssse3:SSSE3
+	sse4_1:SSE4_1
+	sse4_2:SSE4_2
+)
+# MIPS_CPU_FEATURES=(
+# 	msa:MSA
+# )
+# S390_CPU_FEATURES=(
+# 	z13:Z13
+# 	z14:Z14
+# )
+
+CPU_FEATURES_MAP=(
+	"${ARM_CPU_FEATURES[@]/#/cpu_flags_arm_}"
+	"${PPC_CPU_FEATURES[@]/#/cpu_flags_ppc_}"
+	"${X86_CPU_FEATURES[@]/#/cpu_flags_x86_}"
+	# "${MIPS_CPU_FEATURES[@]/#/cpu_flags_mips_}"
+	# "${S390_CPU_FEATURES[@]/#/cpu_flags_s390_}"
+)
+
+IUSE_TEST_BACKENDS=(
+	"adolc"
+	"boost"
+	"cholmod"
+	"fftw"
+	"klu"
+	"metis"
+	"opengl"
+	"pastix"
+	"pocketfft"
+	"sparsehash"
+	"spqr"
+	"superlu"
+	"umfpack"
+)
+
+IUSE="
+	debug
+	blas lapack
+	${CPU_FEATURES_MAP[*]%:*}
+	cuda cuda-clang hip
+	doc mathjax
+	openmp
+	test ${IUSE_TEST_BACKENDS[*]}
+"
+# zvector
+
+REQUIRED_USE="
+	lapack? (
+		blas
+	)
+	test? (
+		|| ( ${IUSE_TEST_BACKENDS[*]} )
+		cuda-clang? (
+			!openmp
+			${LLVM_REQUIRED_USE}
+		)
+	)
+"
+
+# Tests failing again because of compiler issues; bugs #932646, #943401
+RESTRICT="!test? ( test )"
+FORTRAN_DEPEND="virtual/fortran"
+
+BDEPEND="
+	doc? (
+		app-text/doxygen[dot]
+		dev-texlive/texlive-bibtexextra
+		dev-texlive/texlive-fontsextra
+		dev-texlive/texlive-fontutils
+		dev-texlive/texlive-latex
+		dev-texlive/texlive-latexextra
+		mathjax? ( dev-libs/mathjax )
+	)
+	test? (
+		virtual/pkgconfig
+		lapack? (
+			${PYTHON_DEPS}
+		)
+		spqr? (
+			cholmod? (
+				blas? (
+					lapack? (
+						${FORTRAN_DEPEND}
+					)
+				)
+			)
+		)
+		pastix? ( ${FORTRAN_DEPEND} )
+	)
+	blas? ( ${FORTRAN_DEPEND} )
+	lapack? ( ${FORTRAN_DEPEND} )
+"
+
+TEST_BACKENDS="
+		adolc? ( sci-libs/adolc[sparse] )
+		boost? ( dev-libs/boost )
+		cholmod? ( sci-libs/cholmod:=[cuda?] )
+		fftw? ( sci-libs/fftw[openmp?] )
+		klu? ( sci-libs/klu:= )
+		metis? (
+			sci-libs/metis[openmp?]
+			sci-libs/pastix[metis]
+		)
+		opengl? (
+			media-libs/freeglut
+			media-libs/glew
+			media-libs/libglvnd
+		)
+		pastix? (
+			sci-libs/pastix[-mpi]
+			|| (
+				sci-libs/pastix[scotch]
+				sci-libs/pastix[metis]
+			)
+		)
+		pocketfft? ( dev-libs/pocketfft )
+		sparsehash? (
+			amd64? ( dev-cpp/sparsehash )
+			arm64? ( dev-cpp/sparsehash )
+			ppc64? ( dev-cpp/sparsehash )
+			x86?   ( dev-cpp/sparsehash )
+		)
+		spqr? ( sci-libs/spqr:= )
+		superlu? ( sci-libs/superlu:= )
+		umfpack? ( sci-libs/umfpack:= )
+"
+
+DEPEND="
+	test? (
+		cuda? (
+			!cuda-clang? (
+				dev-util/nvidia-cuda-toolkit
+			)
+			cuda-clang? (
+				$(llvm_gen_dep '
+					llvm-core/clang:${LLVM_SLOT}
+					llvm-runtimes/clang-runtime:${LLVM_SLOT}[llvm_targets_NVPTX,offload,openmp]
+				')
+			)
+		)
+		hip? ( dev-util/hip )
+		!blas? (
+			virtual/blas
+			!lapack? (
+				virtual/lapacke
+			)
+		)
+		${TEST_BACKENDS}
+	)
+"
+
+PATCHES=(
+	"${FILESDIR}/${PN}-3.3.9-max-macro.patch"
+	"${FILESDIR}/${PN}-3.4.0-doc-nocompress.patch" # bug 830064
+	"${FILESDIR}/${PN}-3.4.0-buildstring.patch"
+	"${FILESDIR}/${PN}-3.4.1-cxxstandard-17.patch"
+
+	"${FILESDIR}/${PN}-3.4.0-c++-20.patch"
+
+	"${FILESDIR}/${PN}-3.4.1-bug1213-link-with-Eigen3-Eigen.patch"
+
+	"${FILESDIR}/${PN}-5.0.1-cmake-GNUInstallDirs.patch"
+	"${FILESDIR}/${PN}-5.0.1-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch"
+
+	"${DISTDIR}/${P}_p1.patch"
+	"${DISTDIR}/${P}_p2.patch"
+)
+
+# TODO should be in cuda.eclass
+cuda_get_host_compiler() {
+	if [[ -n "${NVCC_CCBIN}" ]]; then
+		echo "${NVCC_CCBIN}"
+		return
+	fi
+
+	if [[ -n "${CUDAHOSTCXX}" ]]; then
+		echo "${CUDAHOSTCXX}"
+		return
+	fi
+
+	einfo "Trying to find working CUDA host compiler"
+
+	if ! tc-is-gcc && ! tc-is-clang; then
+		die "$(tc-get-compiler-type) compiler is not supported"
+	fi
+
+	local compiler compiler_type compiler_version
+	local package package_version
+	local -x NVCC_CCBIN
+	local NVCC_CCBIN_default
+
+	compiler_type="$(tc-get-compiler-type)"
+	compiler_version="$("${compiler_type}-major-version")"
+
+	# try the default compiler first
+	NVCC_CCBIN="$(tc-getCXX)"
+	NVCC_CCBIN_default="${NVCC_CCBIN}-${compiler_version}"
+
+	compiler="${NVCC_CCBIN/%-${compiler_version}}"
+
+	# store the package so we can re-use it later
+	package="sys-devel/${compiler_type}"
+	package_version="${package}"
+
+	ebegin "testing ${NVCC_CCBIN_default} (default)"
+
+	while ! nvcc -v -ccbin "${NVCC_CCBIN}" - -x cu <<<"int main(){}" &>> "${T}/cuda_get_host_compiler.log" ; do
+		eend 1
+
+		while true; do
+			# prepare next version
+			if ! package_version="<$(best_version "${package_version}")"; then
+				die "could not find a supported version of ${compiler}"
+			fi
+
+			NVCC_CCBIN="${compiler}-$(ver_cut 1 "${package_version/#<${package}-/}")"
+
+			[[ "${NVCC_CCBIN}" != "${NVCC_CCBIN_default}" ]] && break
+		done
+		ebegin "testing ${NVCC_CCBIN}"
+	done
+	eend $?
+
+	echo "${NVCC_CCBIN}"
+	export NVCC_CCBIN
+}
+
+pkg_pretend() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+}
+
+pkg_setup() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+
+	if use lapack; then
+		python-any-r1_pkg_setup
+	fi
+
+	if { use test && { use spqr && use cholmod && use blas && use lapack; } || use pastix; } \
+		|| use blas \
+		|| use lapack \
+		; then
+		fortran-2_pkg_setup
+	fi
+
+	if use test && use cuda && use cuda-clang; then
+		llvm-r2_pkg_setup
+	fi
+}
+
+src_unpack() {
+	if [[ ${PV} = *9999* ]] ; then
+		git-r3_src_unpack
+	else
+		unpack "${P}.tar.bz2"
+	fi
+
+	if use test && use lapack; then
+		pushd "${S}/lapack" > /dev/null || die
+		unpack "${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz"
+		popd > /dev/null || die
+	fi
+}
+
+src_prepare() {
+	# run patches here as we patch in test/
+	cmake_src_prepare
+
+	if use test && use lapack; then
+		pushd "${S}" > /dev/null || die
+		eapply "${FILESDIR}/${PN}-5.0.1-fix-lapack_testing.py.patch"
+		popd > /dev/null || die
+	fi
+}
+
+src_configure() {
+	if use lapack; then
+		# bug 878987
+		# multiple definition of `cgesdd_'
+		filter-lto
+	fi
+
+	local mycmakeargs=(
+		-DCMAKE_CXX_STANDARD="20"
+		-DCMAKE_POSITION_INDEPENDENT_CODE="yes"
+
+		-DEIGEN_BUILD_TESTING="$(usex test)" # Enable creation of Eigen tests.
+
+		-DEIGEN_BUILD_BLAS="$(usex blas)" # Toggles the building of the Eigen Blas library
+		-DEIGEN_BUILD_LAPACK="$(usex blas "$(usex lapack)")" # Toggles the building of the included Eigen LAPACK library
+
+		-DEIGEN_BUILD_DOC="$(usex doc)" # Enable creation of Eigen documentation
+		-DEIGEN_BUILD_PKGCONFIG="yes" # Build pkg-config .pc file for Eigen
+	)
+
+	append-cxxflags "-DEIGEN_USE_OPENBLAS_BFLOAT16=0"
+
+	if use blas; then
+		mycmakeargs+=(
+			-DBUILD_SHARED_LIBS="yes"
+			-DEIGEN_BUILD_SHARED_LIBS="yes"
+		)
+
+		if use lapack; then
+			mycmakeargs+=(
+				-DCMAKE_POLICY_DEFAULT_CMP0148="OLD" # FindPythonInterp
+				-DEIGEN_ENABLE_LAPACK_TESTS="$(usex test)"
+			)
+		fi
+	fi
+
+	if use doc || use test; then
+		mycmakeargs+=(
+			# needs Qt4
+			-DEIGEN_TEST_NOQT="yes" # Disable Qt support in unit tests
+		)
+	fi
+
+	if use doc; then
+		mycmakeargs+=(
+			-DEIGEN_DOC_USE_MATHJAX="$(usex mathjax)" # Use MathJax for rendering math in HTML docs
+			-DEIGEN_INTERNAL_DOCUMENTATION=no # Build internal documentation
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DEIGEN_LEAVE_TEST_IN_ALL_TARGET=yes # Leaves tests in the all target, needed by ctest for automatic building
+
+			# the OpenGL testsuite is extremely brittle, bug #712808
+			-DEIGEN_TEST_OPENGL="$(usex opengl)" # Enable OpenGL support in unit tests
+			-DEIGEN_TEST_OPENMP="$(usex openmp)" # Enable/Disable OpenMP in tests/examples
+
+			-DEIGEN_TEST_EXTERNAL_BLAS="$(usex !blas)" # Use external BLAS library for testsuite
+
+			-DEIGEN_TEST_BUILD_DOCUMENTATION="no" # $(usex doc)" # Test building the doxygen documentation
+
+			-DEIGEN_DEBUG_ASSERTS="$(usex debug)" # Enable advanced debugging of assertions
+			-DEIGEN_SPLIT_LARGE_TESTS="yes" # Split large tests into smaller executables
+
+			-DEIGEN_TEST_CUDA="$(usex cuda)" # Enable CUDA support in unit tests
+			-DEIGEN_TEST_CUDA_CLANG="$(usex cuda "$(usex cuda-clang)")" # Use clang instead of nvcc to compile the CUDA tests
+
+			-DEIGEN_TEST_HIP="$(usex hip)" # Add HIP support.
+
+			# -DEIGEN_TEST_SYCL="$(usex sycl)" # Add Sycl support.
+			# -DEIGEN_SYCL_TRISYCL="no" # Use the triSYCL Sycl implementation (ComputeCPP by default).
+
+			$(cmake_use_find_package adolc Adolc)
+			$(cmake_use_find_package boost Boost)
+			$(cmake_use_find_package cholmod CHOLMOD)
+			$(cmake_use_find_package fftw FFTW )
+			$(cmake_use_find_package klu KLU)
+			-DCMAKE_DISABLE_FIND_PACKAGE_MPREAL=yes
+			# $(cmake_use_find_package opengl OpenGL) # EIGEN_TEST_OPENGL
+			# $(cmake_use_find_package openmp OpenMP) # EIGEN_TEST_OPENMP
+			$(cmake_use_find_package pastix PASTIX)
+			# prevent pastix_nompi.h lookup it no longer exists, we enforce this via deps
+			-DPASTIX_pastix_nompi.h_INCLUDE_DIRS="FOUND"
+
+			-DPOCKETFFT="$(usex pocketfft)"
+			$(cmake_use_find_package sparsehash GoogleHash)
+			$(cmake_use_find_package spqr SPQR)
+			$(cmake_use_find_package superlu SuperLU)
+			$(cmake_use_find_package umfpack UMFPACK)
+		)
+
+		if use arm; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use arm64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON64="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use amd64 || use x86; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_32BIT=no # Force generating 32bit code.
+				# -DEIGEN_TEST_X87=no # Force using X87 instructions. Implies no vectorization.
+				-DEIGEN_TEST_SSE2="$(usex cpu_flags_x86_sse2)"
+				-DEIGEN_TEST_SSE3="$(usex cpu_flags_x86_sse3)"
+				-DEIGEN_TEST_SSSE3="$(usex cpu_flags_x86_ssse3)"
+				-DEIGEN_TEST_FMA="$(usex cpu_flags_x86_fma3)"
+				-DEIGEN_TEST_SSE4_1="$(usex cpu_flags_x86_sse4_1)"
+				-DEIGEN_TEST_SSE4_2="$(usex cpu_flags_x86_sse4_2)"
+				-DEIGEN_TEST_AVX="$(usex cpu_flags_x86_avx)"
+				-DEIGEN_TEST_F16C="$(usex cpu_flags_x86_f16c)"
+				-DEIGEN_TEST_AVX2="$(usex cpu_flags_x86_avx2)"
+				-DEIGEN_TEST_AVX512="$(usex cpu_flags_x86_avx512f)"
+				-DEIGEN_TEST_AVX512DQ="$(usex cpu_flags_x86_avx512dq)"
+			)
+		fi
+
+		if use mips; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_MSA=no # Enable/Disable MSA in tests/examples
+			)
+		fi
+
+		if use ppc || use ppc64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_ALTIVEC="$(usex cpu_flags_ppc_altivec)"
+				-DEIGEN_TEST_VSX="$(usex cpu_flags_ppc_vsx)"
+			)
+		fi
+
+		if use s390; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_Z13=no # Enable/Disable S390X(zEC13) ZVECTOR in tests/examples
+				# -DEIGEN_TEST_Z14=no # Enable/Disable S390X(zEC14) ZVECTOR in tests/examples
+			)
+		fi
+
+		if use cuda; then
+			cuda_add_sandbox -w
+
+			if use cuda-clang; then
+				local llvm_prefix
+				llvm_prefix="$(get_llvm_prefix -b)"
+
+				# NVCCFLAGS gets injected into CMAKE_CXX_FLAGS, which means we need to use clang as gcc will fail with
+				# error: unrecognized command-line option
+				if ! tc-is-clang; then
+					export CC="${CHOST}-clang-${LLVM_SLOT}"
+					export CXX="${CHOST}-clang++-${LLVM_SLOT}"
+				fi
+
+				NVCCFLAGS="${NVCCFLAGS:+${NVCCFLAGS} }--libomptarget-nvptx-bc-path=${llvm_prefix}/$(get_libdir)/nvptx64-nvidia-cuda/libomptarget-nvptx.bc"
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CHOST}-clang++-${LLVM_SLOT}"
+				)
+			else
+				cuda_get_host_compiler
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CUDAHOSTCXX}"
+				)
+				if [[ -v CUDACXX ]]; then
+					mycmakeargs+=(
+						-DCUDA_NVCC_EXECUTABLE="${CUDACXX}"
+						-DCMAKE_POLICY_DEFAULT_CMP0146="OLD" # FindCUDA
+					)
+				fi
+			fi
+
+			if [[ "${CUDA_VERBOSE}" == true ]]; then
+				mycmakeargs+=(
+					-DCUDA_VERBOSE_BUILD="yes"
+				)
+				NVCCFLAGS+=" -v"
+			fi
+
+			if [[ -v CUDAARCHS ]]; then
+				mycmakeargs+=(
+					# TODO this needs to be lowest first for eigen
+					-DEIGEN_CUDA_COMPUTE_ARCH="${CUDAARCHS}"
+				)
+			fi
+
+			# CUDAFLAGS is used by cmake
+			# NVCCFLAGS is used by cuda.eclass
+			mycmakeargs+=(
+				-DEIGEN_CUDA_CXX_FLAGS="${NVCCFLAGS}"
+
+				-DCUDA_USE_STATIC_CUDA_RUNTIME="no"
+			)
+		fi
+
+		if use opengl; then
+			mycmakeargs+=(
+				-DOpenGL_GL_PREFERENCE="GLVND"
+			)
+		fi
+
+		if use pocketfft; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_CXX11=yes
+			)
+		fi
+	fi
+
+	cmake_src_configure
+}
+
+src_compile() {
+	local targets=()
+
+	if use blas; then
+		targets+=( blas )
+		if use lapack; then
+			targets+=( lapack )
+		fi
+	fi
+
+	if use test; then
+		targets+=( buildtests )
+
+		if use cuda || use hip; then
+			targets+=( buildtests_gpu )
+		fi
+
+		# tests generate random data, which fails for some seeds
+		# we solve this via test reruns now
+		# export EIGEN_SEED=712808
+	fi
+
+	# we add doc last to capture results for buildtests
+	if use doc; then
+		targets+=( doc )
+	fi
+
+	if [[ -n "${targets[*]}" ]]; then
+		cmake_src_compile "${targets[@]}"
+	fi
+}
+
+src_test() {
+	local CMAKE_SKIP_TESTS=(
+		"^ref_8$"
+	)
+
+	if use cholmod && use blas && use lapack; then
+		CMAKE_SKIP_TESTS+=(
+		"^cholmod_support_21$"
+		"^cholmod_support_22$"
+		)
+	fi
+
+	if use cuda; then
+		cuda_add_sandbox -w
+	fi
+
+	if use klu && use blas; then
+		CMAKE_SKIP_TESTS+=(
+			"^klu_support_1$"
+			"^klu_support_2$"
+		)
+	fi
+
+	if use lapack; then
+		CMAKE_SKIP_TESTS+=(
+			"^LAPACK-xlintsts_stest_in$"
+			"^LAPACK-xeigtsts_sep_in$"
+			"^LAPACK-xeigtsts_svd_in$"
+			"^LAPACK-xlintstd_dtest_in$"
+			"^LAPACK-xeigtstd_sep_in$"
+			"^LAPACK-xeigtstd_svd_in$"
+			"^LAPACK-xlintstc_ctest_in$"
+			"^LAPACK-xeigtstc_svd_in$"
+		)
+	fi
+
+	local myctestargs=(
+		-j1 # otherwise breaks due to cmake reruns
+		--repeat until-pass:50
+	)
+
+	if use opengl; then
+		virtx \
+			cmake_src_test
+	else
+		cmake_src_test
+	fi
+}
+
+src_install() {
+	local DOCS=()
+	cmake_src_install
+
+	if use doc; then
+		pushd "${BUILD_DIR}/doc" > /dev/null || die
+		dodoc -r html
+		popd > /dev/null || die
+	fi
+}
diff --git a/dev-cpp/eigen/eigen-3.4.9999.ebuild b/dev-cpp/eigen/eigen-3.4.9999.ebuild
new file mode 100644
index 000000000000..0d0b2ca43801
--- /dev/null
+++ b/dev-cpp/eigen/eigen-3.4.9999.ebuild
@@ -0,0 +1,645 @@
+# Copyright 1999-2026 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+LLVM_COMPAT=( {21..23} )
+LLVM_OPTIONAL="cuda-clang"
+
+PYTHON_COMPAT=( python3_{13..14} )
+
+FORTRAN_NEEDED="no"
+
+LAPACK_ADDONS_PV="3.4.1"
+
+inherit cmake cuda flag-o-matic fortran-2 llvm-r2 python-any-r1 toolchain-funcs virtualx
+
+DESCRIPTION="C++ template library for linear algebra"
+HOMEPAGE="https://eigen.tuxfamily.org/index.php?title=Main_Page"
+
+if [[ ${PV} = *9999* ]] ; then
+	inherit git-r3
+	EGIT_REPO_URI="https://gitlab.com/lib${PN}/${PN}.git"
+	if [[ ${PV} = *.9999* ]] ; then
+		EGIT_BRANCH="$(ver_cut 1-2)"
+	fi
+else
+	SRC_URI="
+		https://gitlab.com/lib${PN}/${PN}/-/archive/${PV}/${P}.tar.bz2
+	"
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~arm64-macos ~x64-macos"
+fi
+
+SRC_URI+="
+	test? (
+		lapack? (
+			https://downloads.tuxfamily.org/${PN}/lapack_addons_${LAPACK_ADDONS_PV}.tgz
+				-> ${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz
+		)
+	)
+"
+
+LICENSE="MPL-2.0"
+SLOT="3/$(ver_cut 1-2)"
+
+# The following lines are shamelessly stolen from ffmpeg-9999.ebuild with modifications
+ARM_CPU_FEATURES=(
+	neon:NEON
+)
+PPC_CPU_FEATURES=(
+	altivec:ALTIVEC
+	vsx:VSX
+)
+X86_CPU_FEATURES=(
+	avx:AVX
+	avx2:AVX2
+	avx512f:AVX512
+	avx512dq:AVX512DQ
+	f16c:FP16C
+	fma3:FMA
+	popcnt:POPCNT
+	sse:SSE
+	sse2:SSE2
+	sse3:SSE3
+	ssse3:SSSE3
+	sse4_1:SSE4_1
+	sse4_2:SSE4_2
+)
+# MIPS_CPU_FEATURES=(
+# 	msa:MSA
+# )
+# S390_CPU_FEATURES=(
+# 	z13:Z13
+# 	z14:Z14
+# )
+
+CPU_FEATURES_MAP=(
+	"${ARM_CPU_FEATURES[@]/#/cpu_flags_arm_}"
+	"${PPC_CPU_FEATURES[@]/#/cpu_flags_ppc_}"
+	"${X86_CPU_FEATURES[@]/#/cpu_flags_x86_}"
+	# "${MIPS_CPU_FEATURES[@]/#/cpu_flags_mips_}"
+	# "${S390_CPU_FEATURES[@]/#/cpu_flags_s390_}"
+)
+
+IUSE_TEST_BACKENDS=(
+	"adolc"
+	"boost"
+	"cholmod"
+	"fftw"
+	"klu"
+	"metis"
+	"opengl"
+	"pastix"
+	"pocketfft"
+	"sparsehash"
+	"spqr"
+	"superlu"
+	"umfpack"
+)
+
+IUSE="
+	debug
+	blas lapack
+	${CPU_FEATURES_MAP[*]%:*}
+	cuda cuda-clang hip
+	doc mathjax
+	openmp
+	test ${IUSE_TEST_BACKENDS[*]}
+"
+# zvector
+
+REQUIRED_USE="
+	lapack? (
+		blas
+	)
+	test? (
+		|| ( ${IUSE_TEST_BACKENDS[*]} )
+		cuda-clang? (
+			!openmp
+			${LLVM_REQUIRED_USE}
+		)
+	)
+"
+
+# Tests failing again because of compiler issues; bugs #932646, #943401
+RESTRICT="!test? ( test )"
+FORTRAN_DEPEND="virtual/fortran"
+
+BDEPEND="
+	doc? (
+		app-text/doxygen[dot]
+		dev-texlive/texlive-bibtexextra
+		dev-texlive/texlive-fontsextra
+		dev-texlive/texlive-fontutils
+		dev-texlive/texlive-latex
+		dev-texlive/texlive-latexextra
+		mathjax? ( dev-libs/mathjax )
+	)
+	test? (
+		virtual/pkgconfig
+		lapack? (
+			${PYTHON_DEPS}
+		)
+		spqr? (
+			cholmod? (
+				blas? (
+					lapack? (
+						${FORTRAN_DEPEND}
+					)
+				)
+			)
+		)
+		pastix? ( ${FORTRAN_DEPEND} )
+	)
+	blas? ( ${FORTRAN_DEPEND} )
+	lapack? ( ${FORTRAN_DEPEND} )
+"
+
+TEST_BACKENDS="
+		adolc? ( sci-libs/adolc[sparse] )
+		boost? ( dev-libs/boost )
+		cholmod? ( sci-libs/cholmod:=[cuda?] )
+		fftw? ( sci-libs/fftw[openmp?] )
+		klu? ( sci-libs/klu:= )
+		metis? (
+			sci-libs/metis[openmp?]
+			sci-libs/pastix[metis]
+		)
+		opengl? (
+			media-libs/freeglut
+			media-libs/glew
+			media-libs/libglvnd
+		)
+		pastix? (
+			sci-libs/pastix[-mpi]
+			|| (
+				sci-libs/pastix[scotch]
+				sci-libs/pastix[metis]
+			)
+		)
+		pocketfft? ( dev-libs/pocketfft )
+		sparsehash? (
+			amd64? ( dev-cpp/sparsehash )
+			arm64? ( dev-cpp/sparsehash )
+			ppc64? ( dev-cpp/sparsehash )
+			x86?   ( dev-cpp/sparsehash )
+		)
+		spqr? ( sci-libs/spqr:= )
+		superlu? ( sci-libs/superlu:= )
+		umfpack? ( sci-libs/umfpack:= )
+"
+
+DEPEND="
+	test? (
+		cuda? (
+			!cuda-clang? (
+				dev-util/nvidia-cuda-toolkit
+			)
+			cuda-clang? (
+				$(llvm_gen_dep '
+					llvm-core/clang:${LLVM_SLOT}
+					llvm-runtimes/clang-runtime:${LLVM_SLOT}[llvm_targets_NVPTX,offload,openmp]
+				')
+			)
+		)
+		hip? ( dev-util/hip )
+		!blas? (
+			virtual/blas
+			!lapack? (
+				virtual/lapacke
+			)
+		)
+		${TEST_BACKENDS}
+	)
+"
+
+PATCHES=(
+	"${FILESDIR}/${PN}-3.3.9-max-macro.patch"
+	"${FILESDIR}/${PN}-3.4.0-doc-nocompress.patch" # bug 830064
+	"${FILESDIR}/${PN}-3.4.0-buildstring.patch"
+	"${FILESDIR}/${PN}-3.4.1-cxxstandard-17.patch"
+
+	"${FILESDIR}/${PN}-3.4.0-c++-20.patch"
+
+	"${FILESDIR}/${PN}-3.4.1-bug1213-link-with-Eigen3-Eigen.patch"
+
+	"${FILESDIR}/${PN}-5.0.1-cmake-GNUInstallDirs.patch"
+	"${FILESDIR}/${PN}-5.0.1-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch"
+)
+
+# TODO should be in cuda.eclass
+cuda_get_host_compiler() {
+	if [[ -n "${NVCC_CCBIN}" ]]; then
+		echo "${NVCC_CCBIN}"
+		return
+	fi
+
+	if [[ -n "${CUDAHOSTCXX}" ]]; then
+		echo "${CUDAHOSTCXX}"
+		return
+	fi
+
+	einfo "Trying to find working CUDA host compiler"
+
+	if ! tc-is-gcc && ! tc-is-clang; then
+		die "$(tc-get-compiler-type) compiler is not supported"
+	fi
+
+	local compiler compiler_type compiler_version
+	local package package_version
+	local -x NVCC_CCBIN
+	local NVCC_CCBIN_default
+
+	compiler_type="$(tc-get-compiler-type)"
+	compiler_version="$("${compiler_type}-major-version")"
+
+	# try the default compiler first
+	NVCC_CCBIN="$(tc-getCXX)"
+	NVCC_CCBIN_default="${NVCC_CCBIN}-${compiler_version}"
+
+	compiler="${NVCC_CCBIN/%-${compiler_version}}"
+
+	# store the package so we can re-use it later
+	package="sys-devel/${compiler_type}"
+	package_version="${package}"
+
+	ebegin "testing ${NVCC_CCBIN_default} (default)"
+
+	while ! nvcc -v -ccbin "${NVCC_CCBIN}" - -x cu <<<"int main(){}" &>> "${T}/cuda_get_host_compiler.log" ; do
+		eend 1
+
+		while true; do
+			# prepare next version
+			if ! package_version="<$(best_version "${package_version}")"; then
+				die "could not find a supported version of ${compiler}"
+			fi
+
+			NVCC_CCBIN="${compiler}-$(ver_cut 1 "${package_version/#<${package}-/}")"
+
+			[[ "${NVCC_CCBIN}" != "${NVCC_CCBIN_default}" ]] && break
+		done
+		ebegin "testing ${NVCC_CCBIN}"
+	done
+	eend $?
+
+	echo "${NVCC_CCBIN}"
+	export NVCC_CCBIN
+}
+
+pkg_pretend() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+}
+
+pkg_setup() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+
+	if use lapack; then
+		python-any-r1_pkg_setup
+	fi
+
+	if { use test && { use spqr && use cholmod && use blas && use lapack; } || use pastix; } \
+		|| use blas \
+		|| use lapack \
+		; then
+		fortran-2_pkg_setup
+	fi
+
+	if use test && use cuda && use cuda-clang; then
+		llvm-r2_pkg_setup
+	fi
+}
+
+src_unpack() {
+	if [[ ${PV} = *9999* ]] ; then
+		git-r3_src_unpack
+	else
+		unpack "${P}.tar.bz2"
+	fi
+
+	if use test && use lapack; then
+		pushd "${S}/lapack" > /dev/null || die
+		unpack "${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz"
+		popd > /dev/null || die
+	fi
+}
+
+src_prepare() {
+	# run patches here as we patch in test/
+	cmake_src_prepare
+
+	if use test && use lapack; then
+		pushd "${S}" > /dev/null || die
+		eapply "${FILESDIR}/${PN}-5.0.1-fix-lapack_testing.py.patch"
+		popd > /dev/null || die
+	fi
+}
+
+src_configure() {
+	if use lapack; then
+		# bug 878987
+		# multiple definition of `cgesdd_'
+		filter-lto
+	fi
+
+	local mycmakeargs=(
+		-DCMAKE_CXX_STANDARD="20"
+		-DCMAKE_POSITION_INDEPENDENT_CODE="yes"
+
+		-DEIGEN_BUILD_TESTING="$(usex test)" # Enable creation of Eigen tests.
+
+		-DEIGEN_BUILD_BLAS="$(usex blas)" # Toggles the building of the Eigen Blas library
+		-DEIGEN_BUILD_LAPACK="$(usex blas "$(usex lapack)")" # Toggles the building of the included Eigen LAPACK library
+
+		-DEIGEN_BUILD_DOC="$(usex doc)" # Enable creation of Eigen documentation
+		-DEIGEN_BUILD_PKGCONFIG="yes" # Build pkg-config .pc file for Eigen
+	)
+
+	append-cxxflags "-DEIGEN_USE_OPENBLAS_BFLOAT16=0"
+
+	if use blas; then
+		mycmakeargs+=(
+			-DBUILD_SHARED_LIBS="yes"
+			-DEIGEN_BUILD_SHARED_LIBS="yes"
+		)
+
+		if use lapack; then
+			mycmakeargs+=(
+				-DCMAKE_POLICY_DEFAULT_CMP0148="OLD" # FindPythonInterp
+				-DEIGEN_ENABLE_LAPACK_TESTS="$(usex test)"
+			)
+		fi
+	fi
+
+	if use doc || use test; then
+		mycmakeargs+=(
+			# needs Qt4
+			-DEIGEN_TEST_NOQT="yes" # Disable Qt support in unit tests
+		)
+	fi
+
+	if use doc; then
+		mycmakeargs+=(
+			-DEIGEN_DOC_USE_MATHJAX="$(usex mathjax)" # Use MathJax for rendering math in HTML docs
+			-DEIGEN_INTERNAL_DOCUMENTATION=no # Build internal documentation
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DEIGEN_LEAVE_TEST_IN_ALL_TARGET=yes # Leaves tests in the all target, needed by ctest for automatic building
+
+			# the OpenGL testsuite is extremely brittle, bug #712808
+			-DEIGEN_TEST_OPENGL="$(usex opengl)" # Enable OpenGL support in unit tests
+			-DEIGEN_TEST_OPENMP="$(usex openmp)" # Enable/Disable OpenMP in tests/examples
+
+			-DEIGEN_TEST_EXTERNAL_BLAS="$(usex !blas)" # Use external BLAS library for testsuite
+
+			-DEIGEN_TEST_BUILD_DOCUMENTATION="no" # $(usex doc)" # Test building the doxygen documentation
+
+			-DEIGEN_DEBUG_ASSERTS="$(usex debug)" # Enable advanced debugging of assertions
+			-DEIGEN_SPLIT_LARGE_TESTS="yes" # Split large tests into smaller executables
+
+			-DEIGEN_TEST_CUDA="$(usex cuda)" # Enable CUDA support in unit tests
+			-DEIGEN_TEST_CUDA_CLANG="$(usex cuda "$(usex cuda-clang)")" # Use clang instead of nvcc to compile the CUDA tests
+
+			-DEIGEN_TEST_HIP="$(usex hip)" # Add HIP support.
+
+			# -DEIGEN_TEST_SYCL="$(usex sycl)" # Add Sycl support.
+			# -DEIGEN_SYCL_TRISYCL="no" # Use the triSYCL Sycl implementation (ComputeCPP by default).
+
+			$(cmake_use_find_package adolc Adolc)
+			$(cmake_use_find_package boost Boost)
+			$(cmake_use_find_package cholmod CHOLMOD)
+			$(cmake_use_find_package fftw FFTW )
+			$(cmake_use_find_package klu KLU)
+			-DCMAKE_DISABLE_FIND_PACKAGE_MPREAL=yes
+			# $(cmake_use_find_package opengl OpenGL) # EIGEN_TEST_OPENGL
+			# $(cmake_use_find_package openmp OpenMP) # EIGEN_TEST_OPENMP
+			$(cmake_use_find_package pastix PASTIX)
+			# prevent pastix_nompi.h lookup it no longer exists, we enforce this via deps
+			-DPASTIX_pastix_nompi.h_INCLUDE_DIRS="FOUND"
+
+			-DPOCKETFFT="$(usex pocketfft)"
+			$(cmake_use_find_package sparsehash GoogleHash)
+			$(cmake_use_find_package spqr SPQR)
+			$(cmake_use_find_package superlu SuperLU)
+			$(cmake_use_find_package umfpack UMFPACK)
+		)
+
+		if use arm; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use arm64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON64="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use amd64 || use x86; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_32BIT=no # Force generating 32bit code.
+				# -DEIGEN_TEST_X87=no # Force using X87 instructions. Implies no vectorization.
+				-DEIGEN_TEST_SSE2="$(usex cpu_flags_x86_sse2)"
+				-DEIGEN_TEST_SSE3="$(usex cpu_flags_x86_sse3)"
+				-DEIGEN_TEST_SSSE3="$(usex cpu_flags_x86_ssse3)"
+				-DEIGEN_TEST_FMA="$(usex cpu_flags_x86_fma3)"
+				-DEIGEN_TEST_SSE4_1="$(usex cpu_flags_x86_sse4_1)"
+				-DEIGEN_TEST_SSE4_2="$(usex cpu_flags_x86_sse4_2)"
+				-DEIGEN_TEST_AVX="$(usex cpu_flags_x86_avx)"
+				-DEIGEN_TEST_F16C="$(usex cpu_flags_x86_f16c)"
+				-DEIGEN_TEST_AVX2="$(usex cpu_flags_x86_avx2)"
+				-DEIGEN_TEST_AVX512="$(usex cpu_flags_x86_avx512f)"
+				-DEIGEN_TEST_AVX512DQ="$(usex cpu_flags_x86_avx512dq)"
+			)
+		fi
+
+		if use mips; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_MSA=no # Enable/Disable MSA in tests/examples
+			)
+		fi
+
+		if use ppc || use ppc64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_ALTIVEC="$(usex cpu_flags_ppc_altivec)"
+				-DEIGEN_TEST_VSX="$(usex cpu_flags_ppc_vsx)"
+			)
+		fi
+
+		if use s390; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_Z13=no # Enable/Disable S390X(zEC13) ZVECTOR in tests/examples
+				# -DEIGEN_TEST_Z14=no # Enable/Disable S390X(zEC14) ZVECTOR in tests/examples
+			)
+		fi
+
+		if use cuda; then
+			cuda_add_sandbox -w
+
+			if use cuda-clang; then
+				local llvm_prefix
+				llvm_prefix="$(get_llvm_prefix -b)"
+
+				# NVCCFLAGS gets injected into CMAKE_CXX_FLAGS, which means we need to use clang as gcc will fail with
+				# error: unrecognized command-line option
+				if ! tc-is-clang; then
+					export CC="${CHOST}-clang-${LLVM_SLOT}"
+					export CXX="${CHOST}-clang++-${LLVM_SLOT}"
+				fi
+
+				NVCCFLAGS="${NVCCFLAGS:+${NVCCFLAGS} }--libomptarget-nvptx-bc-path=${llvm_prefix}/$(get_libdir)/nvptx64-nvidia-cuda/libomptarget-nvptx.bc"
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CHOST}-clang++-${LLVM_SLOT}"
+				)
+			else
+				cuda_get_host_compiler
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CUDAHOSTCXX}"
+				)
+				if [[ -v CUDACXX ]]; then
+					mycmakeargs+=(
+						-DCUDA_NVCC_EXECUTABLE="${CUDACXX}"
+						-DCMAKE_POLICY_DEFAULT_CMP0146="OLD" # FindCUDA
+					)
+				fi
+			fi
+
+			if [[ "${CUDA_VERBOSE}" == true ]]; then
+				mycmakeargs+=(
+					-DCUDA_VERBOSE_BUILD="yes"
+				)
+				NVCCFLAGS+=" -v"
+			fi
+
+			if [[ -v CUDAARCHS ]]; then
+				mycmakeargs+=(
+					# TODO this needs to be lowest first for eigen
+					-DEIGEN_CUDA_COMPUTE_ARCH="${CUDAARCHS}"
+				)
+			fi
+
+			# CUDAFLAGS is used by cmake
+			# NVCCFLAGS is used by cuda.eclass
+			mycmakeargs+=(
+				-DEIGEN_CUDA_CXX_FLAGS="${NVCCFLAGS}"
+
+				-DCUDA_USE_STATIC_CUDA_RUNTIME="no"
+			)
+		fi
+
+		if use opengl; then
+			mycmakeargs+=(
+				-DOpenGL_GL_PREFERENCE="GLVND"
+			)
+		fi
+
+		if use pocketfft; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_CXX11=yes
+			)
+		fi
+	fi
+
+	cmake_src_configure
+}
+
+src_compile() {
+	local targets=()
+
+	if use blas; then
+		targets+=( blas )
+		if use lapack; then
+			targets+=( lapack )
+		fi
+	fi
+
+	if use test; then
+		targets+=( buildtests )
+
+		if use cuda || use hip; then
+			targets+=( buildtests_gpu )
+		fi
+
+		# tests generate random data, which fails for some seeds
+		# we solve this via test reruns now
+		# export EIGEN_SEED=712808
+	fi
+
+	# we add doc last to capture results for buildtests
+	if use doc; then
+		targets+=( doc )
+	fi
+
+	if [[ -n "${targets[*]}" ]]; then
+		cmake_src_compile "${targets[@]}"
+	fi
+}
+
+src_test() {
+	local CMAKE_SKIP_TESTS=(
+		"^ref_8$"
+	)
+
+	if use cholmod && use blas && use lapack; then
+		CMAKE_SKIP_TESTS+=(
+		"^cholmod_support_21$"
+		"^cholmod_support_22$"
+		)
+	fi
+
+	if use cuda; then
+		cuda_add_sandbox -w
+	fi
+
+	if use klu && use blas; then
+		CMAKE_SKIP_TESTS+=(
+			"^klu_support_1$"
+			"^klu_support_2$"
+		)
+	fi
+
+	if use lapack; then
+		CMAKE_SKIP_TESTS+=(
+			"^LAPACK-xlintsts_stest_in$"
+			"^LAPACK-xeigtsts_sep_in$"
+			"^LAPACK-xeigtsts_svd_in$"
+			"^LAPACK-xlintstd_dtest_in$"
+			"^LAPACK-xeigtstd_sep_in$"
+			"^LAPACK-xeigtstd_svd_in$"
+			"^LAPACK-xlintstc_ctest_in$"
+			"^LAPACK-xeigtstc_svd_in$"
+		)
+	fi
+
+	local myctestargs=(
+		-j1 # otherwise breaks due to cmake reruns
+		--repeat until-pass:50
+	)
+
+	if use opengl; then
+		virtx \
+			cmake_src_test
+	else
+		cmake_src_test
+	fi
+}
+
+src_install() {
+	local DOCS=()
+	cmake_src_install
+
+	if use doc; then
+		pushd "${BUILD_DIR}/doc" > /dev/null || die
+		dodoc -r html
+		popd > /dev/null || die
+	fi
+}
diff --git a/dev-cpp/eigen/eigen-5.0.1.ebuild b/dev-cpp/eigen/eigen-5.0.1.ebuild
new file mode 100644
index 000000000000..2a62c78642c4
--- /dev/null
+++ b/dev-cpp/eigen/eigen-5.0.1.ebuild
@@ -0,0 +1,665 @@
+# Copyright 1999-2026 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+LLVM_COMPAT=( {21..23} )
+LLVM_OPTIONAL="cuda-clang"
+
+PYTHON_COMPAT=( python3_{13..14} )
+
+FORTRAN_NEEDED="no"
+
+LAPACK_ADDONS_PV="3.4.1"
+
+inherit cmake cuda flag-o-matic fortran-2 llvm-r2 python-any-r1 toolchain-funcs virtualx
+
+DESCRIPTION="C++ template library for linear algebra"
+HOMEPAGE="https://eigen.tuxfamily.org/index.php?title=Main_Page"
+
+if [[ ${PV} = *9999* ]] ; then
+	inherit git-r3
+	EGIT_REPO_URI="https://gitlab.com/lib${PN}/${PN}.git"
+	if [[ ${PV} = *.9999* ]] ; then
+		EGIT_BRANCH="$(ver_cut 1-2)"
+	fi
+else
+	SRC_URI="
+		https://gitlab.com/lib${PN}/${PN}/-/archive/${PV}/${P}.tar.bz2
+	"
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~arm64-macos ~x64-macos"
+fi
+
+SRC_URI+="
+	test? (
+		lapack? (
+			https://downloads.tuxfamily.org/${PN}/lapack_addons_${LAPACK_ADDONS_PV}.tgz
+				-> ${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz
+		)
+	)
+"
+
+LICENSE="MPL-2.0"
+SLOT="3/$(ver_cut 1-2)"
+
+# The following lines are shamelessly stolen from ffmpeg-9999.ebuild with modifications
+ARM_CPU_FEATURES=(
+	neon:NEON
+)
+PPC_CPU_FEATURES=(
+	altivec:ALTIVEC
+	vsx:VSX
+)
+X86_CPU_FEATURES=(
+	avx:AVX
+	avx2:AVX2
+	avx512f:AVX512
+	avx512dq:AVX512DQ
+	f16c:FP16C
+	fma3:FMA
+	popcnt:POPCNT
+	sse:SSE
+	sse2:SSE2
+	sse3:SSE3
+	ssse3:SSSE3
+	sse4_1:SSE4_1
+	sse4_2:SSE4_2
+)
+# MIPS_CPU_FEATURES=(
+# 	msa:MSA
+# )
+# S390_CPU_FEATURES=(
+# 	z13:Z13
+# 	z14:Z14
+# )
+
+CPU_FEATURES_MAP=(
+	"${ARM_CPU_FEATURES[@]/#/cpu_flags_arm_}"
+	"${PPC_CPU_FEATURES[@]/#/cpu_flags_ppc_}"
+	"${X86_CPU_FEATURES[@]/#/cpu_flags_x86_}"
+	# "${MIPS_CPU_FEATURES[@]/#/cpu_flags_mips_}"
+	# "${S390_CPU_FEATURES[@]/#/cpu_flags_s390_}"
+)
+
+IUSE_TEST_BACKENDS=(
+	"adolc"
+	"boost"
+	"cholmod"
+	"fftw"
+	"klu"
+	"metis"
+	"opengl"
+	"pastix"
+	"pocketfft"
+	"sparsehash"
+	"spqr"
+	"superlu"
+	"umfpack"
+)
+
+IUSE="
+	debug
+	blas lapack
+	${CPU_FEATURES_MAP[*]%:*}
+	cuda cuda-clang hip
+	doc mathjax
+	openmp
+	test ${IUSE_TEST_BACKENDS[*]}
+"
+# zvector
+
+REQUIRED_USE="
+	lapack? (
+		blas
+	)
+	test? (
+		|| ( ${IUSE_TEST_BACKENDS[*]} )
+		cuda-clang? (
+			!openmp
+			${LLVM_REQUIRED_USE}
+		)
+	)
+"
+
+# Tests failing again because of compiler issues; bugs #932646, #943401
+RESTRICT="!test? ( test )"
+FORTRAN_DEPEND="virtual/fortran"
+
+BDEPEND="
+	doc? (
+		app-text/doxygen[dot]
+		dev-texlive/texlive-bibtexextra
+		dev-texlive/texlive-fontsextra
+		dev-texlive/texlive-fontutils
+		dev-texlive/texlive-latex
+		dev-texlive/texlive-latexextra
+		mathjax? ( dev-libs/mathjax )
+	)
+	test? (
+		virtual/pkgconfig
+		lapack? (
+			${PYTHON_DEPS}
+		)
+		spqr? (
+			cholmod? (
+				blas? (
+					lapack? (
+						${FORTRAN_DEPEND}
+					)
+				)
+			)
+		)
+		pastix? ( ${FORTRAN_DEPEND} )
+	)
+	blas? ( ${FORTRAN_DEPEND} )
+	lapack? ( ${FORTRAN_DEPEND} )
+"
+
+TEST_BACKENDS="
+		adolc? ( sci-libs/adolc[sparse] )
+		boost? ( dev-libs/boost )
+		cholmod? ( sci-libs/cholmod:=[cuda?] )
+		fftw? ( sci-libs/fftw[openmp?] )
+		klu? ( sci-libs/klu:= )
+		metis? (
+			sci-libs/metis[openmp?]
+			sci-libs/pastix[metis]
+		)
+		opengl? (
+			media-libs/freeglut
+			media-libs/glew
+			media-libs/libglvnd
+		)
+		pastix? (
+			sci-libs/pastix[-mpi]
+			|| (
+				sci-libs/pastix[scotch]
+				sci-libs/pastix[metis]
+			)
+		)
+		pocketfft? ( dev-libs/pocketfft )
+		sparsehash? (
+			amd64? ( dev-cpp/sparsehash )
+			arm64? ( dev-cpp/sparsehash )
+			ppc64? ( dev-cpp/sparsehash )
+			x86?   ( dev-cpp/sparsehash )
+		)
+		spqr? ( sci-libs/spqr:= )
+		superlu? ( sci-libs/superlu:= )
+		umfpack? ( sci-libs/umfpack:= )
+"
+
+DEPEND="
+	test? (
+		cuda? (
+			!cuda-clang? (
+				dev-util/nvidia-cuda-toolkit
+			)
+			cuda-clang? (
+				$(llvm_gen_dep '
+					llvm-core/clang:${LLVM_SLOT}
+					llvm-runtimes/clang-runtime:${LLVM_SLOT}[llvm_targets_NVPTX,offload,openmp]
+				')
+			)
+		)
+		hip? ( dev-util/hip )
+		!blas? (
+			virtual/blas
+			!lapack? (
+				virtual/lapacke
+			)
+		)
+		${TEST_BACKENDS}
+	)
+"
+
+PATCHES=(
+	"${FILESDIR}/${PN}-3.4.0-doc-nocompress.patch" # bug 830064
+	"${FILESDIR}/${PN}-3.4.0-buildstring.patch"
+	"${FILESDIR}/${PN}-5.0.0-please_protect_your_min_with_parentheses.patch"
+
+	# PRs
+	"${FILESDIR}/${PN}-5.0.0-doxygen-1.14.patch"
+
+	"${FILESDIR}/${PN}-5.0.1-c++-20.patch"
+	"${FILESDIR}/${PN}-5.0.1-cmake-GNUInstallDirs.patch"
+	"${FILESDIR}/${PN}-5.0.1-make-static-libs-optional.patch"
+
+	"${FILESDIR}/${PN}-5.0.1-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch"
+)
+
+# TODO should be in cuda.eclass
+cuda_get_host_compiler() {
+	if [[ -n "${NVCC_CCBIN}" ]]; then
+		echo "${NVCC_CCBIN}"
+		return
+	fi
+
+	if [[ -n "${CUDAHOSTCXX}" ]]; then
+		echo "${CUDAHOSTCXX}"
+		return
+	fi
+
+	einfo "Trying to find working CUDA host compiler"
+
+	if ! tc-is-gcc && ! tc-is-clang; then
+		die "$(tc-get-compiler-type) compiler is not supported"
+	fi
+
+	local compiler compiler_type compiler_version
+	local package package_version
+	local -x NVCC_CCBIN
+	local NVCC_CCBIN_default
+
+	compiler_type="$(tc-get-compiler-type)"
+	compiler_version="$("${compiler_type}-major-version")"
+
+	# try the default compiler first
+	NVCC_CCBIN="$(tc-getCXX)"
+	NVCC_CCBIN_default="${NVCC_CCBIN}-${compiler_version}"
+
+	compiler="${NVCC_CCBIN/%-${compiler_version}}"
+
+	# store the package so we can re-use it later
+	package="sys-devel/${compiler_type}"
+	package_version="${package}"
+
+	ebegin "testing ${NVCC_CCBIN_default} (default)"
+
+	while ! nvcc -v -ccbin "${NVCC_CCBIN}" - -x cu <<<"int main(){}" &>> "${T}/cuda_get_host_compiler.log" ; do
+		eend 1
+
+		while true; do
+			# prepare next version
+			if ! package_version="<$(best_version "${package_version}")"; then
+				die "could not find a supported version of ${compiler}"
+			fi
+
+			NVCC_CCBIN="${compiler}-$(ver_cut 1 "${package_version/#<${package}-/}")"
+
+			[[ "${NVCC_CCBIN}" != "${NVCC_CCBIN_default}" ]] && break
+		done
+		ebegin "testing ${NVCC_CCBIN}"
+	done
+	eend $?
+
+	echo "${NVCC_CCBIN}"
+	export NVCC_CCBIN
+}
+
+pkg_pretend() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+}
+
+pkg_setup() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+
+	if use lapack; then
+		python-any-r1_pkg_setup
+	fi
+
+	if { use test && { use spqr && use cholmod && use blas && use lapack; } || use pastix; } \
+		|| use blas \
+		|| use lapack \
+		; then
+		fortran-2_pkg_setup
+	fi
+
+	if use test && use cuda && use cuda-clang; then
+		llvm-r2_pkg_setup
+	fi
+}
+
+src_unpack() {
+	if [[ ${PV} = *9999* ]] ; then
+		git-r3_src_unpack
+	else
+		unpack "${P}.tar.bz2"
+	fi
+
+	if use test && use lapack; then
+		pushd "${S}/lapack" > /dev/null || die
+		unpack "${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz"
+		popd > /dev/null || die
+	fi
+}
+
+src_prepare() {
+	# run patches here as we patch in test/
+	cmake_src_prepare
+
+	if use test && use lapack; then
+		pushd "${S}" > /dev/null || die
+		eapply "${FILESDIR}/${PN}-5.0.1-fix-lapack_testing.py.patch"
+		popd > /dev/null || die
+	fi
+}
+
+src_configure() {
+	if use lapack; then
+		# bug 878987
+		# multiple definition of `cgesdd_'
+		filter-lto
+	fi
+
+	local mycmakeargs=(
+		-DCMAKE_CXX_STANDARD="20"
+		-DCMAKE_POSITION_INDEPENDENT_CODE="yes"
+
+		-DEIGEN_BUILD_TESTING="$(usex test)" # Enable creation of Eigen tests.
+
+		-DEIGEN_BUILD_BLAS="$(usex blas)" # Toggles the building of the Eigen Blas library
+		-DEIGEN_BUILD_LAPACK="$(usex blas "$(usex lapack)")" # Toggles the building of the included Eigen LAPACK library
+
+		-DEIGEN_BUILD_DOC="$(usex doc)" # Enable creation of Eigen documentation
+		-DEIGEN_BUILD_PKGCONFIG="yes" # Build pkg-config .pc file for Eigen
+	)
+
+	append-cxxflags "-DEIGEN_USE_OPENBLAS_BFLOAT16=0"
+
+	if use blas; then
+		mycmakeargs+=(
+			-DBUILD_SHARED_LIBS="yes"
+			-DEIGEN_BUILD_SHARED_LIBS="yes"
+			-DEIGEN_BUILD_STATIC_LIBS="yes"
+			-DEIGEN_INSTALL_STATIC_LIBS="yes"
+		)
+
+		if use lapack; then
+			mycmakeargs+=(
+				-DCMAKE_POLICY_DEFAULT_CMP0148="OLD" # FindPythonInterp
+				-DEIGEN_ENABLE_LAPACK_TESTS="$(usex test)"
+			)
+		fi
+	fi
+
+	if use doc || use test; then
+		mycmakeargs+=(
+			# needs Qt4
+			-DEIGEN_TEST_NOQT="yes" # Disable Qt support in unit tests
+		)
+	fi
+
+	if use doc; then
+		mycmakeargs+=(
+			-DEIGEN_DOC_USE_MATHJAX="$(usex mathjax)" # Use MathJax for rendering math in HTML docs
+			-DEIGEN_INTERNAL_DOCUMENTATION=no # Build internal documentation
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DEIGEN_LEAVE_TEST_IN_ALL_TARGET=yes # Leaves tests in the all target, needed by ctest for automatic building
+
+			# the OpenGL testsuite is extremely brittle, bug #712808
+			-DEIGEN_TEST_OPENGL="$(usex opengl)" # Enable OpenGL support in unit tests
+			-DEIGEN_TEST_OPENMP="$(usex openmp)" # Enable/Disable OpenMP in tests/examples
+
+			-DEIGEN_TEST_EXTERNAL_BLAS="$(usex !blas)" # Use external BLAS library for testsuite
+
+			-DEIGEN_TEST_BUILD_DOCUMENTATION="no" # $(usex doc)" # Test building the doxygen documentation
+
+			-DEIGEN_DEBUG_ASSERTS="$(usex debug)" # Enable advanced debugging of assertions
+			-DEIGEN_SPLIT_LARGE_TESTS="yes" # Split large tests into smaller executables
+
+			-DEIGEN_TEST_CUDA="$(usex cuda)" # Enable CUDA support in unit tests
+			-DEIGEN_TEST_CUDA_CLANG="$(usex cuda "$(usex cuda-clang)")" # Use clang instead of nvcc to compile the CUDA tests
+
+			-DEIGEN_TEST_HIP="$(usex hip)" # Add HIP support.
+
+			# -DEIGEN_TEST_SYCL="$(usex sycl)" # Add Sycl support.
+			# -DEIGEN_SYCL_TRISYCL="no" # Use the triSYCL Sycl implementation (ComputeCPP by default).
+
+			$(cmake_use_find_package adolc Adolc)
+			$(cmake_use_find_package boost Boost)
+			$(cmake_use_find_package cholmod CHOLMOD)
+			# -DDUCCFFT="$(usex ducc)"
+			-DDUCC_ROOT="DUCCFFT"
+			-DDUCCFFT="NOTFOUND"
+			$(cmake_use_find_package fftw FFTW )
+			$(cmake_use_find_package klu KLU)
+			-DCMAKE_DISABLE_FIND_PACKAGE_MPREAL=yes
+			# $(cmake_use_find_package opengl OpenGL) # EIGEN_TEST_OPENGL
+			# $(cmake_use_find_package openmp OpenMP) # EIGEN_TEST_OPENMP
+			$(cmake_use_find_package pastix PASTIX)
+			# prevent pastix_nompi.h lookup it no longer exists, we enforce this via deps
+			-DPASTIX_pastix_nompi.h_INCLUDE_DIRS="FOUND"
+
+			-DPOCKETFFT="$(usex pocketfft)"
+			$(cmake_use_find_package sparsehash GoogleHash)
+			$(cmake_use_find_package spqr SPQR)
+			$(cmake_use_find_package superlu SuperLU)
+			$(cmake_use_find_package umfpack UMFPACK)
+		)
+
+		if use arm; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use arm64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON64="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use amd64 || use x86; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_32BIT=no # Force generating 32bit code.
+				# -DEIGEN_TEST_X87=no # Force using X87 instructions. Implies no vectorization.
+				-DEIGEN_TEST_SSE2="$(usex cpu_flags_x86_sse2)"
+				-DEIGEN_TEST_SSE3="$(usex cpu_flags_x86_sse3)"
+				-DEIGEN_TEST_SSSE3="$(usex cpu_flags_x86_ssse3)"
+				-DEIGEN_TEST_FMA="$(usex cpu_flags_x86_fma3)"
+				-DEIGEN_TEST_SSE4_1="$(usex cpu_flags_x86_sse4_1)"
+				-DEIGEN_TEST_SSE4_2="$(usex cpu_flags_x86_sse4_2)"
+				-DEIGEN_TEST_AVX="$(usex cpu_flags_x86_avx)"
+				-DEIGEN_TEST_F16C="$(usex cpu_flags_x86_f16c)"
+				-DEIGEN_TEST_AVX2="$(usex cpu_flags_x86_avx2)"
+				-DEIGEN_TEST_AVX512="$(usex cpu_flags_x86_avx512f)"
+				-DEIGEN_TEST_AVX512DQ="$(usex cpu_flags_x86_avx512dq)"
+			)
+		fi
+
+		if use mips; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_MSA=no # Enable/Disable MSA in tests/examples
+			)
+		fi
+
+		if use ppc || use ppc64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_ALTIVEC="$(usex cpu_flags_ppc_altivec)"
+				-DEIGEN_TEST_VSX="$(usex cpu_flags_ppc_vsx)"
+			)
+		fi
+
+		if use s390; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_Z13=no # Enable/Disable S390X(zEC13) ZVECTOR in tests/examples
+				# -DEIGEN_TEST_Z14=no # Enable/Disable S390X(zEC14) ZVECTOR in tests/examples
+			)
+		fi
+
+		if use cuda; then
+			cuda_add_sandbox -w
+
+			if use cuda-clang; then
+				local llvm_prefix
+				llvm_prefix="$(get_llvm_prefix -b)"
+
+				# NVCCFLAGS gets injected into CMAKE_CXX_FLAGS, which means we need to use clang as gcc will fail with
+				# error: unrecognized command-line option
+				if ! tc-is-clang; then
+					export CC="${CHOST}-clang-${LLVM_SLOT}"
+					export CXX="${CHOST}-clang++-${LLVM_SLOT}"
+				fi
+
+				NVCCFLAGS="${NVCCFLAGS:+${NVCCFLAGS} }--libomptarget-nvptx-bc-path=${llvm_prefix}/$(get_libdir)/nvptx64-nvidia-cuda/libomptarget-nvptx.bc"
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CHOST}-clang++-${LLVM_SLOT}"
+				)
+			else
+				cuda_get_host_compiler
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CUDAHOSTCXX}"
+				)
+				if [[ -v CUDACXX ]]; then
+					mycmakeargs+=(
+						-DCUDA_NVCC_EXECUTABLE="${CUDACXX}"
+						-DCMAKE_POLICY_DEFAULT_CMP0146="OLD" # FindCUDA
+					)
+				fi
+			fi
+
+			if [[ "${CUDA_VERBOSE}" == true ]]; then
+				mycmakeargs+=(
+					-DCUDA_VERBOSE_BUILD="yes"
+				)
+				NVCCFLAGS+=" -v"
+			fi
+
+			if [[ -v CUDAARCHS ]]; then
+				mycmakeargs+=(
+					# TODO this needs to be lowest first for eigen
+					-DEIGEN_CUDA_COMPUTE_ARCH="${CUDAARCHS}"
+				)
+			fi
+
+			# CUDAFLAGS is used by cmake
+			# NVCCFLAGS is used by cuda.eclass
+			mycmakeargs+=(
+				-DEIGEN_CUDA_CXX_FLAGS="${NVCCFLAGS}"
+
+				-DCUDA_USE_STATIC_CUDA_RUNTIME="no"
+			)
+		fi
+
+		if use opengl; then
+			mycmakeargs+=(
+				-DOpenGL_GL_PREFERENCE="GLVND"
+			)
+		fi
+
+		if use pocketfft; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_CXX11=yes
+			)
+		fi
+	fi
+
+	cmake_src_configure
+}
+
+src_compile() {
+	local targets=()
+
+	if use blas; then
+		targets+=( blas )
+		if use lapack; then
+			targets+=( lapack )
+		fi
+	fi
+
+	if use test; then
+		targets+=( buildtests )
+
+		if use cuda || use hip; then
+			targets+=( buildtests_gpu )
+		fi
+
+		# tests generate random data, which fails for some seeds
+		# we solve this via test reruns now
+		# export EIGEN_SEED=712808
+	fi
+
+	# we add doc last to capture results for buildtests
+	if use doc; then
+		targets+=( doc )
+	fi
+
+	if [[ -n "${targets[*]}" ]]; then
+		cmake_src_compile "${targets[@]}"
+	fi
+}
+
+src_test() {
+	local CMAKE_SKIP_TESTS=(
+		"^ref_8$"
+	)
+
+	if ! use blas; then
+		CMAKE_SKIP_TESTS+=(
+			"^nomalloc_1$" # smoketest
+			"^nomalloc_2$"
+			"^nomalloc_3$"
+			"^nomalloc_4$"
+
+			"^product_notemporary_1$"
+			"^product_notemporary_2$"
+			"^product_notemporary_3$"
+			"^product_notemporary_4$"
+		)
+	fi
+
+	if use cholmod && use blas && use lapack; then
+		CMAKE_SKIP_TESTS+=(
+		"^cholmod_support_21$"
+		"^cholmod_support_22$"
+		)
+	fi
+
+	if use cuda; then
+		cuda_add_sandbox -w
+	fi
+
+	if use klu && use blas; then
+		CMAKE_SKIP_TESTS+=(
+			"^klu_support_1$"
+			"^klu_support_2$"
+		)
+	fi
+
+	if use lapack; then
+		CMAKE_SKIP_TESTS+=(
+			"^LAPACK-xlintsts_stest_in$"
+			"^LAPACK-xeigtsts_sep_in$"
+			"^LAPACK-xeigtsts_svd_in$"
+			"^LAPACK-xlintstd_dtest_in$"
+			"^LAPACK-xeigtstd_sep_in$"
+			"^LAPACK-xeigtstd_svd_in$"
+			"^LAPACK-xlintstc_ctest_in$"
+			"^LAPACK-xeigtstc_svd_in$"
+		)
+	fi
+
+	local myctestargs=(
+		-j1 # otherwise breaks due to cmake reruns
+		--repeat until-pass:50
+	)
+
+	if use opengl; then
+		virtx \
+			cmake_src_test
+	else
+		cmake_src_test
+	fi
+}
+
+src_install() {
+	local DOCS=()
+	cmake_src_install
+
+	if use doc; then
+		pushd "${BUILD_DIR}/doc" > /dev/null || die
+		dodoc -r html
+		popd > /dev/null || die
+	fi
+}
diff --git a/dev-cpp/eigen/eigen-5.0.9999.ebuild b/dev-cpp/eigen/eigen-5.0.9999.ebuild
new file mode 100644
index 000000000000..2a62c78642c4
--- /dev/null
+++ b/dev-cpp/eigen/eigen-5.0.9999.ebuild
@@ -0,0 +1,665 @@
+# Copyright 1999-2026 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+LLVM_COMPAT=( {21..23} )
+LLVM_OPTIONAL="cuda-clang"
+
+PYTHON_COMPAT=( python3_{13..14} )
+
+FORTRAN_NEEDED="no"
+
+LAPACK_ADDONS_PV="3.4.1"
+
+inherit cmake cuda flag-o-matic fortran-2 llvm-r2 python-any-r1 toolchain-funcs virtualx
+
+DESCRIPTION="C++ template library for linear algebra"
+HOMEPAGE="https://eigen.tuxfamily.org/index.php?title=Main_Page"
+
+if [[ ${PV} = *9999* ]] ; then
+	inherit git-r3
+	EGIT_REPO_URI="https://gitlab.com/lib${PN}/${PN}.git"
+	if [[ ${PV} = *.9999* ]] ; then
+		EGIT_BRANCH="$(ver_cut 1-2)"
+	fi
+else
+	SRC_URI="
+		https://gitlab.com/lib${PN}/${PN}/-/archive/${PV}/${P}.tar.bz2
+	"
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~arm64-macos ~x64-macos"
+fi
+
+SRC_URI+="
+	test? (
+		lapack? (
+			https://downloads.tuxfamily.org/${PN}/lapack_addons_${LAPACK_ADDONS_PV}.tgz
+				-> ${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz
+		)
+	)
+"
+
+LICENSE="MPL-2.0"
+SLOT="3/$(ver_cut 1-2)"
+
+# The following lines are shamelessly stolen from ffmpeg-9999.ebuild with modifications
+ARM_CPU_FEATURES=(
+	neon:NEON
+)
+PPC_CPU_FEATURES=(
+	altivec:ALTIVEC
+	vsx:VSX
+)
+X86_CPU_FEATURES=(
+	avx:AVX
+	avx2:AVX2
+	avx512f:AVX512
+	avx512dq:AVX512DQ
+	f16c:FP16C
+	fma3:FMA
+	popcnt:POPCNT
+	sse:SSE
+	sse2:SSE2
+	sse3:SSE3
+	ssse3:SSSE3
+	sse4_1:SSE4_1
+	sse4_2:SSE4_2
+)
+# MIPS_CPU_FEATURES=(
+# 	msa:MSA
+# )
+# S390_CPU_FEATURES=(
+# 	z13:Z13
+# 	z14:Z14
+# )
+
+CPU_FEATURES_MAP=(
+	"${ARM_CPU_FEATURES[@]/#/cpu_flags_arm_}"
+	"${PPC_CPU_FEATURES[@]/#/cpu_flags_ppc_}"
+	"${X86_CPU_FEATURES[@]/#/cpu_flags_x86_}"
+	# "${MIPS_CPU_FEATURES[@]/#/cpu_flags_mips_}"
+	# "${S390_CPU_FEATURES[@]/#/cpu_flags_s390_}"
+)
+
+IUSE_TEST_BACKENDS=(
+	"adolc"
+	"boost"
+	"cholmod"
+	"fftw"
+	"klu"
+	"metis"
+	"opengl"
+	"pastix"
+	"pocketfft"
+	"sparsehash"
+	"spqr"
+	"superlu"
+	"umfpack"
+)
+
+IUSE="
+	debug
+	blas lapack
+	${CPU_FEATURES_MAP[*]%:*}
+	cuda cuda-clang hip
+	doc mathjax
+	openmp
+	test ${IUSE_TEST_BACKENDS[*]}
+"
+# zvector
+
+REQUIRED_USE="
+	lapack? (
+		blas
+	)
+	test? (
+		|| ( ${IUSE_TEST_BACKENDS[*]} )
+		cuda-clang? (
+			!openmp
+			${LLVM_REQUIRED_USE}
+		)
+	)
+"
+
+# Tests failing again because of compiler issues; bugs #932646, #943401
+RESTRICT="!test? ( test )"
+FORTRAN_DEPEND="virtual/fortran"
+
+BDEPEND="
+	doc? (
+		app-text/doxygen[dot]
+		dev-texlive/texlive-bibtexextra
+		dev-texlive/texlive-fontsextra
+		dev-texlive/texlive-fontutils
+		dev-texlive/texlive-latex
+		dev-texlive/texlive-latexextra
+		mathjax? ( dev-libs/mathjax )
+	)
+	test? (
+		virtual/pkgconfig
+		lapack? (
+			${PYTHON_DEPS}
+		)
+		spqr? (
+			cholmod? (
+				blas? (
+					lapack? (
+						${FORTRAN_DEPEND}
+					)
+				)
+			)
+		)
+		pastix? ( ${FORTRAN_DEPEND} )
+	)
+	blas? ( ${FORTRAN_DEPEND} )
+	lapack? ( ${FORTRAN_DEPEND} )
+"
+
+TEST_BACKENDS="
+		adolc? ( sci-libs/adolc[sparse] )
+		boost? ( dev-libs/boost )
+		cholmod? ( sci-libs/cholmod:=[cuda?] )
+		fftw? ( sci-libs/fftw[openmp?] )
+		klu? ( sci-libs/klu:= )
+		metis? (
+			sci-libs/metis[openmp?]
+			sci-libs/pastix[metis]
+		)
+		opengl? (
+			media-libs/freeglut
+			media-libs/glew
+			media-libs/libglvnd
+		)
+		pastix? (
+			sci-libs/pastix[-mpi]
+			|| (
+				sci-libs/pastix[scotch]
+				sci-libs/pastix[metis]
+			)
+		)
+		pocketfft? ( dev-libs/pocketfft )
+		sparsehash? (
+			amd64? ( dev-cpp/sparsehash )
+			arm64? ( dev-cpp/sparsehash )
+			ppc64? ( dev-cpp/sparsehash )
+			x86?   ( dev-cpp/sparsehash )
+		)
+		spqr? ( sci-libs/spqr:= )
+		superlu? ( sci-libs/superlu:= )
+		umfpack? ( sci-libs/umfpack:= )
+"
+
+DEPEND="
+	test? (
+		cuda? (
+			!cuda-clang? (
+				dev-util/nvidia-cuda-toolkit
+			)
+			cuda-clang? (
+				$(llvm_gen_dep '
+					llvm-core/clang:${LLVM_SLOT}
+					llvm-runtimes/clang-runtime:${LLVM_SLOT}[llvm_targets_NVPTX,offload,openmp]
+				')
+			)
+		)
+		hip? ( dev-util/hip )
+		!blas? (
+			virtual/blas
+			!lapack? (
+				virtual/lapacke
+			)
+		)
+		${TEST_BACKENDS}
+	)
+"
+
+PATCHES=(
+	"${FILESDIR}/${PN}-3.4.0-doc-nocompress.patch" # bug 830064
+	"${FILESDIR}/${PN}-3.4.0-buildstring.patch"
+	"${FILESDIR}/${PN}-5.0.0-please_protect_your_min_with_parentheses.patch"
+
+	# PRs
+	"${FILESDIR}/${PN}-5.0.0-doxygen-1.14.patch"
+
+	"${FILESDIR}/${PN}-5.0.1-c++-20.patch"
+	"${FILESDIR}/${PN}-5.0.1-cmake-GNUInstallDirs.patch"
+	"${FILESDIR}/${PN}-5.0.1-make-static-libs-optional.patch"
+
+	"${FILESDIR}/${PN}-5.0.1-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch"
+)
+
+# TODO should be in cuda.eclass
+cuda_get_host_compiler() {
+	if [[ -n "${NVCC_CCBIN}" ]]; then
+		echo "${NVCC_CCBIN}"
+		return
+	fi
+
+	if [[ -n "${CUDAHOSTCXX}" ]]; then
+		echo "${CUDAHOSTCXX}"
+		return
+	fi
+
+	einfo "Trying to find working CUDA host compiler"
+
+	if ! tc-is-gcc && ! tc-is-clang; then
+		die "$(tc-get-compiler-type) compiler is not supported"
+	fi
+
+	local compiler compiler_type compiler_version
+	local package package_version
+	local -x NVCC_CCBIN
+	local NVCC_CCBIN_default
+
+	compiler_type="$(tc-get-compiler-type)"
+	compiler_version="$("${compiler_type}-major-version")"
+
+	# try the default compiler first
+	NVCC_CCBIN="$(tc-getCXX)"
+	NVCC_CCBIN_default="${NVCC_CCBIN}-${compiler_version}"
+
+	compiler="${NVCC_CCBIN/%-${compiler_version}}"
+
+	# store the package so we can re-use it later
+	package="sys-devel/${compiler_type}"
+	package_version="${package}"
+
+	ebegin "testing ${NVCC_CCBIN_default} (default)"
+
+	while ! nvcc -v -ccbin "${NVCC_CCBIN}" - -x cu <<<"int main(){}" &>> "${T}/cuda_get_host_compiler.log" ; do
+		eend 1
+
+		while true; do
+			# prepare next version
+			if ! package_version="<$(best_version "${package_version}")"; then
+				die "could not find a supported version of ${compiler}"
+			fi
+
+			NVCC_CCBIN="${compiler}-$(ver_cut 1 "${package_version/#<${package}-/}")"
+
+			[[ "${NVCC_CCBIN}" != "${NVCC_CCBIN_default}" ]] && break
+		done
+		ebegin "testing ${NVCC_CCBIN}"
+	done
+	eend $?
+
+	echo "${NVCC_CCBIN}"
+	export NVCC_CCBIN
+}
+
+pkg_pretend() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+}
+
+pkg_setup() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+
+	if use lapack; then
+		python-any-r1_pkg_setup
+	fi
+
+	if { use test && { use spqr && use cholmod && use blas && use lapack; } || use pastix; } \
+		|| use blas \
+		|| use lapack \
+		; then
+		fortran-2_pkg_setup
+	fi
+
+	if use test && use cuda && use cuda-clang; then
+		llvm-r2_pkg_setup
+	fi
+}
+
+src_unpack() {
+	if [[ ${PV} = *9999* ]] ; then
+		git-r3_src_unpack
+	else
+		unpack "${P}.tar.bz2"
+	fi
+
+	if use test && use lapack; then
+		pushd "${S}/lapack" > /dev/null || die
+		unpack "${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz"
+		popd > /dev/null || die
+	fi
+}
+
+src_prepare() {
+	# run patches here as we patch in test/
+	cmake_src_prepare
+
+	if use test && use lapack; then
+		pushd "${S}" > /dev/null || die
+		eapply "${FILESDIR}/${PN}-5.0.1-fix-lapack_testing.py.patch"
+		popd > /dev/null || die
+	fi
+}
+
+src_configure() {
+	if use lapack; then
+		# bug 878987
+		# multiple definition of `cgesdd_'
+		filter-lto
+	fi
+
+	local mycmakeargs=(
+		-DCMAKE_CXX_STANDARD="20"
+		-DCMAKE_POSITION_INDEPENDENT_CODE="yes"
+
+		-DEIGEN_BUILD_TESTING="$(usex test)" # Enable creation of Eigen tests.
+
+		-DEIGEN_BUILD_BLAS="$(usex blas)" # Toggles the building of the Eigen Blas library
+		-DEIGEN_BUILD_LAPACK="$(usex blas "$(usex lapack)")" # Toggles the building of the included Eigen LAPACK library
+
+		-DEIGEN_BUILD_DOC="$(usex doc)" # Enable creation of Eigen documentation
+		-DEIGEN_BUILD_PKGCONFIG="yes" # Build pkg-config .pc file for Eigen
+	)
+
+	append-cxxflags "-DEIGEN_USE_OPENBLAS_BFLOAT16=0"
+
+	if use blas; then
+		mycmakeargs+=(
+			-DBUILD_SHARED_LIBS="yes"
+			-DEIGEN_BUILD_SHARED_LIBS="yes"
+			-DEIGEN_BUILD_STATIC_LIBS="yes"
+			-DEIGEN_INSTALL_STATIC_LIBS="yes"
+		)
+
+		if use lapack; then
+			mycmakeargs+=(
+				-DCMAKE_POLICY_DEFAULT_CMP0148="OLD" # FindPythonInterp
+				-DEIGEN_ENABLE_LAPACK_TESTS="$(usex test)"
+			)
+		fi
+	fi
+
+	if use doc || use test; then
+		mycmakeargs+=(
+			# needs Qt4
+			-DEIGEN_TEST_NOQT="yes" # Disable Qt support in unit tests
+		)
+	fi
+
+	if use doc; then
+		mycmakeargs+=(
+			-DEIGEN_DOC_USE_MATHJAX="$(usex mathjax)" # Use MathJax for rendering math in HTML docs
+			-DEIGEN_INTERNAL_DOCUMENTATION=no # Build internal documentation
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DEIGEN_LEAVE_TEST_IN_ALL_TARGET=yes # Leaves tests in the all target, needed by ctest for automatic building
+
+			# the OpenGL testsuite is extremely brittle, bug #712808
+			-DEIGEN_TEST_OPENGL="$(usex opengl)" # Enable OpenGL support in unit tests
+			-DEIGEN_TEST_OPENMP="$(usex openmp)" # Enable/Disable OpenMP in tests/examples
+
+			-DEIGEN_TEST_EXTERNAL_BLAS="$(usex !blas)" # Use external BLAS library for testsuite
+
+			-DEIGEN_TEST_BUILD_DOCUMENTATION="no" # $(usex doc)" # Test building the doxygen documentation
+
+			-DEIGEN_DEBUG_ASSERTS="$(usex debug)" # Enable advanced debugging of assertions
+			-DEIGEN_SPLIT_LARGE_TESTS="yes" # Split large tests into smaller executables
+
+			-DEIGEN_TEST_CUDA="$(usex cuda)" # Enable CUDA support in unit tests
+			-DEIGEN_TEST_CUDA_CLANG="$(usex cuda "$(usex cuda-clang)")" # Use clang instead of nvcc to compile the CUDA tests
+
+			-DEIGEN_TEST_HIP="$(usex hip)" # Add HIP support.
+
+			# -DEIGEN_TEST_SYCL="$(usex sycl)" # Add Sycl support.
+			# -DEIGEN_SYCL_TRISYCL="no" # Use the triSYCL Sycl implementation (ComputeCPP by default).
+
+			$(cmake_use_find_package adolc Adolc)
+			$(cmake_use_find_package boost Boost)
+			$(cmake_use_find_package cholmod CHOLMOD)
+			# -DDUCCFFT="$(usex ducc)"
+			-DDUCC_ROOT="DUCCFFT"
+			-DDUCCFFT="NOTFOUND"
+			$(cmake_use_find_package fftw FFTW )
+			$(cmake_use_find_package klu KLU)
+			-DCMAKE_DISABLE_FIND_PACKAGE_MPREAL=yes
+			# $(cmake_use_find_package opengl OpenGL) # EIGEN_TEST_OPENGL
+			# $(cmake_use_find_package openmp OpenMP) # EIGEN_TEST_OPENMP
+			$(cmake_use_find_package pastix PASTIX)
+			# prevent pastix_nompi.h lookup it no longer exists, we enforce this via deps
+			-DPASTIX_pastix_nompi.h_INCLUDE_DIRS="FOUND"
+
+			-DPOCKETFFT="$(usex pocketfft)"
+			$(cmake_use_find_package sparsehash GoogleHash)
+			$(cmake_use_find_package spqr SPQR)
+			$(cmake_use_find_package superlu SuperLU)
+			$(cmake_use_find_package umfpack UMFPACK)
+		)
+
+		if use arm; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use arm64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON64="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use amd64 || use x86; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_32BIT=no # Force generating 32bit code.
+				# -DEIGEN_TEST_X87=no # Force using X87 instructions. Implies no vectorization.
+				-DEIGEN_TEST_SSE2="$(usex cpu_flags_x86_sse2)"
+				-DEIGEN_TEST_SSE3="$(usex cpu_flags_x86_sse3)"
+				-DEIGEN_TEST_SSSE3="$(usex cpu_flags_x86_ssse3)"
+				-DEIGEN_TEST_FMA="$(usex cpu_flags_x86_fma3)"
+				-DEIGEN_TEST_SSE4_1="$(usex cpu_flags_x86_sse4_1)"
+				-DEIGEN_TEST_SSE4_2="$(usex cpu_flags_x86_sse4_2)"
+				-DEIGEN_TEST_AVX="$(usex cpu_flags_x86_avx)"
+				-DEIGEN_TEST_F16C="$(usex cpu_flags_x86_f16c)"
+				-DEIGEN_TEST_AVX2="$(usex cpu_flags_x86_avx2)"
+				-DEIGEN_TEST_AVX512="$(usex cpu_flags_x86_avx512f)"
+				-DEIGEN_TEST_AVX512DQ="$(usex cpu_flags_x86_avx512dq)"
+			)
+		fi
+
+		if use mips; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_MSA=no # Enable/Disable MSA in tests/examples
+			)
+		fi
+
+		if use ppc || use ppc64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_ALTIVEC="$(usex cpu_flags_ppc_altivec)"
+				-DEIGEN_TEST_VSX="$(usex cpu_flags_ppc_vsx)"
+			)
+		fi
+
+		if use s390; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_Z13=no # Enable/Disable S390X(zEC13) ZVECTOR in tests/examples
+				# -DEIGEN_TEST_Z14=no # Enable/Disable S390X(zEC14) ZVECTOR in tests/examples
+			)
+		fi
+
+		if use cuda; then
+			cuda_add_sandbox -w
+
+			if use cuda-clang; then
+				local llvm_prefix
+				llvm_prefix="$(get_llvm_prefix -b)"
+
+				# NVCCFLAGS gets injected into CMAKE_CXX_FLAGS, which means we need to use clang as gcc will fail with
+				# error: unrecognized command-line option
+				if ! tc-is-clang; then
+					export CC="${CHOST}-clang-${LLVM_SLOT}"
+					export CXX="${CHOST}-clang++-${LLVM_SLOT}"
+				fi
+
+				NVCCFLAGS="${NVCCFLAGS:+${NVCCFLAGS} }--libomptarget-nvptx-bc-path=${llvm_prefix}/$(get_libdir)/nvptx64-nvidia-cuda/libomptarget-nvptx.bc"
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CHOST}-clang++-${LLVM_SLOT}"
+				)
+			else
+				cuda_get_host_compiler
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CUDAHOSTCXX}"
+				)
+				if [[ -v CUDACXX ]]; then
+					mycmakeargs+=(
+						-DCUDA_NVCC_EXECUTABLE="${CUDACXX}"
+						-DCMAKE_POLICY_DEFAULT_CMP0146="OLD" # FindCUDA
+					)
+				fi
+			fi
+
+			if [[ "${CUDA_VERBOSE}" == true ]]; then
+				mycmakeargs+=(
+					-DCUDA_VERBOSE_BUILD="yes"
+				)
+				NVCCFLAGS+=" -v"
+			fi
+
+			if [[ -v CUDAARCHS ]]; then
+				mycmakeargs+=(
+					# TODO this needs to be lowest first for eigen
+					-DEIGEN_CUDA_COMPUTE_ARCH="${CUDAARCHS}"
+				)
+			fi
+
+			# CUDAFLAGS is used by cmake
+			# NVCCFLAGS is used by cuda.eclass
+			mycmakeargs+=(
+				-DEIGEN_CUDA_CXX_FLAGS="${NVCCFLAGS}"
+
+				-DCUDA_USE_STATIC_CUDA_RUNTIME="no"
+			)
+		fi
+
+		if use opengl; then
+			mycmakeargs+=(
+				-DOpenGL_GL_PREFERENCE="GLVND"
+			)
+		fi
+
+		if use pocketfft; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_CXX11=yes
+			)
+		fi
+	fi
+
+	cmake_src_configure
+}
+
+src_compile() {
+	local targets=()
+
+	if use blas; then
+		targets+=( blas )
+		if use lapack; then
+			targets+=( lapack )
+		fi
+	fi
+
+	if use test; then
+		targets+=( buildtests )
+
+		if use cuda || use hip; then
+			targets+=( buildtests_gpu )
+		fi
+
+		# tests generate random data, which fails for some seeds
+		# we solve this via test reruns now
+		# export EIGEN_SEED=712808
+	fi
+
+	# we add doc last to capture results for buildtests
+	if use doc; then
+		targets+=( doc )
+	fi
+
+	if [[ -n "${targets[*]}" ]]; then
+		cmake_src_compile "${targets[@]}"
+	fi
+}
+
+src_test() {
+	local CMAKE_SKIP_TESTS=(
+		"^ref_8$"
+	)
+
+	if ! use blas; then
+		CMAKE_SKIP_TESTS+=(
+			"^nomalloc_1$" # smoketest
+			"^nomalloc_2$"
+			"^nomalloc_3$"
+			"^nomalloc_4$"
+
+			"^product_notemporary_1$"
+			"^product_notemporary_2$"
+			"^product_notemporary_3$"
+			"^product_notemporary_4$"
+		)
+	fi
+
+	if use cholmod && use blas && use lapack; then
+		CMAKE_SKIP_TESTS+=(
+		"^cholmod_support_21$"
+		"^cholmod_support_22$"
+		)
+	fi
+
+	if use cuda; then
+		cuda_add_sandbox -w
+	fi
+
+	if use klu && use blas; then
+		CMAKE_SKIP_TESTS+=(
+			"^klu_support_1$"
+			"^klu_support_2$"
+		)
+	fi
+
+	if use lapack; then
+		CMAKE_SKIP_TESTS+=(
+			"^LAPACK-xlintsts_stest_in$"
+			"^LAPACK-xeigtsts_sep_in$"
+			"^LAPACK-xeigtsts_svd_in$"
+			"^LAPACK-xlintstd_dtest_in$"
+			"^LAPACK-xeigtstd_sep_in$"
+			"^LAPACK-xeigtstd_svd_in$"
+			"^LAPACK-xlintstc_ctest_in$"
+			"^LAPACK-xeigtstc_svd_in$"
+		)
+	fi
+
+	local myctestargs=(
+		-j1 # otherwise breaks due to cmake reruns
+		--repeat until-pass:50
+	)
+
+	if use opengl; then
+		virtx \
+			cmake_src_test
+	else
+		cmake_src_test
+	fi
+}
+
+src_install() {
+	local DOCS=()
+	cmake_src_install
+
+	if use doc; then
+		pushd "${BUILD_DIR}/doc" > /dev/null || die
+		dodoc -r html
+		popd > /dev/null || die
+	fi
+}
diff --git a/dev-cpp/eigen/eigen-9999.ebuild b/dev-cpp/eigen/eigen-9999.ebuild
new file mode 100644
index 000000000000..804b9e4ea506
--- /dev/null
+++ b/dev-cpp/eigen/eigen-9999.ebuild
@@ -0,0 +1,641 @@
+# Copyright 1999-2026 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+LLVM_COMPAT=( {21..23} )
+LLVM_OPTIONAL="cuda-clang"
+
+PYTHON_COMPAT=( python3_{13..14} )
+
+FORTRAN_NEEDED="no"
+
+LAPACK_ADDONS_PV="3.4.1"
+
+inherit cmake cuda flag-o-matic fortran-2 llvm-r2 python-any-r1 toolchain-funcs virtualx
+
+DESCRIPTION="C++ template library for linear algebra"
+HOMEPAGE="https://eigen.tuxfamily.org/index.php?title=Main_Page"
+
+if [[ ${PV} = *9999* ]] ; then
+	inherit git-r3
+	EGIT_REPO_URI="https://gitlab.com/lib${PN}/${PN}.git"
+	if [[ ${PV} = *.9999* ]] ; then
+		EGIT_BRANCH="$(ver_cut 1-2)"
+	fi
+else
+	SRC_URI="
+		https://gitlab.com/lib${PN}/${PN}/-/archive/${PV}/${P}.tar.bz2
+	"
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~loong ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~arm64-macos ~x64-macos"
+fi
+
+SRC_URI+="
+	test? (
+		lapack? (
+			https://downloads.tuxfamily.org/${PN}/lapack_addons_${LAPACK_ADDONS_PV}.tgz
+				-> ${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz
+		)
+	)
+"
+
+LICENSE="MPL-2.0"
+SLOT="3/$(ver_cut 1-2)"
+
+# The following lines are shamelessly stolen from ffmpeg-9999.ebuild with modifications
+ARM_CPU_FEATURES=(
+	neon:NEON
+)
+PPC_CPU_FEATURES=(
+	altivec:ALTIVEC
+	vsx:VSX
+)
+X86_CPU_FEATURES=(
+	avx:AVX
+	avx2:AVX2
+	avx512f:AVX512
+	avx512dq:AVX512DQ
+	f16c:FP16C
+	fma3:FMA
+	popcnt:POPCNT
+	sse:SSE
+	sse2:SSE2
+	sse3:SSE3
+	ssse3:SSSE3
+	sse4_1:SSE4_1
+	sse4_2:SSE4_2
+)
+# MIPS_CPU_FEATURES=(
+# 	msa:MSA
+# )
+# S390_CPU_FEATURES=(
+# 	z13:Z13
+# 	z14:Z14
+# )
+
+CPU_FEATURES_MAP=(
+	"${ARM_CPU_FEATURES[@]/#/cpu_flags_arm_}"
+	"${PPC_CPU_FEATURES[@]/#/cpu_flags_ppc_}"
+	"${X86_CPU_FEATURES[@]/#/cpu_flags_x86_}"
+	# "${MIPS_CPU_FEATURES[@]/#/cpu_flags_mips_}"
+	# "${S390_CPU_FEATURES[@]/#/cpu_flags_s390_}"
+)
+
+IUSE_TEST_BACKENDS=(
+	"adolc"
+	"boost"
+	"cholmod"
+	"fftw"
+	"klu"
+	"metis"
+	"opengl"
+	"pastix"
+	"pocketfft"
+	"sparsehash"
+	"spqr"
+	"superlu"
+	"umfpack"
+)
+
+IUSE="
+	debug
+	blas lapack
+	${CPU_FEATURES_MAP[*]%:*}
+	cuda cuda-clang hip
+	doc mathjax
+	openmp
+	test ${IUSE_TEST_BACKENDS[*]}
+"
+# zvector
+
+REQUIRED_USE="
+	lapack? (
+		blas
+	)
+	test? (
+		|| ( ${IUSE_TEST_BACKENDS[*]} )
+		cuda-clang? (
+			!openmp
+			${LLVM_REQUIRED_USE}
+		)
+	)
+"
+
+# Tests failing again because of compiler issues; bugs #932646, #943401
+RESTRICT="!test? ( test )"
+FORTRAN_DEPEND="virtual/fortran"
+
+BDEPEND="
+	doc? (
+		app-text/doxygen[dot]
+		dev-texlive/texlive-bibtexextra
+		dev-texlive/texlive-fontsextra
+		dev-texlive/texlive-fontutils
+		dev-texlive/texlive-latex
+		dev-texlive/texlive-latexextra
+		mathjax? ( dev-libs/mathjax )
+	)
+	test? (
+		virtual/pkgconfig
+		lapack? (
+			${PYTHON_DEPS}
+		)
+		spqr? (
+			cholmod? (
+				blas? (
+					lapack? (
+						${FORTRAN_DEPEND}
+					)
+				)
+			)
+		)
+		pastix? ( ${FORTRAN_DEPEND} )
+	)
+	blas? ( ${FORTRAN_DEPEND} )
+	lapack? ( ${FORTRAN_DEPEND} )
+"
+
+TEST_BACKENDS="
+		adolc? ( sci-libs/adolc[sparse] )
+		boost? ( dev-libs/boost )
+		cholmod? ( sci-libs/cholmod:=[cuda?] )
+		fftw? ( sci-libs/fftw[openmp?] )
+		klu? ( sci-libs/klu:= )
+		metis? (
+			sci-libs/metis[openmp?]
+			sci-libs/pastix[metis]
+		)
+		opengl? (
+			media-libs/freeglut
+			media-libs/glew
+			media-libs/libglvnd
+		)
+		pastix? (
+			sci-libs/pastix[-mpi]
+			|| (
+				sci-libs/pastix[scotch]
+				sci-libs/pastix[metis]
+			)
+		)
+		pocketfft? ( dev-libs/pocketfft )
+		sparsehash? (
+			amd64? ( dev-cpp/sparsehash )
+			arm64? ( dev-cpp/sparsehash )
+			ppc64? ( dev-cpp/sparsehash )
+			x86?   ( dev-cpp/sparsehash )
+		)
+		spqr? ( sci-libs/spqr:= )
+		superlu? ( sci-libs/superlu:= )
+		umfpack? ( sci-libs/umfpack:= )
+"
+
+DEPEND="
+	test? (
+		cuda? (
+			!cuda-clang? (
+				dev-util/nvidia-cuda-toolkit
+			)
+			cuda-clang? (
+				$(llvm_gen_dep '
+					llvm-core/clang:${LLVM_SLOT}
+					llvm-runtimes/clang-runtime:${LLVM_SLOT}[llvm_targets_NVPTX,offload,openmp]
+				')
+			)
+		)
+		hip? ( dev-util/hip )
+		!blas? (
+			virtual/blas
+			!lapack? (
+				virtual/lapacke
+			)
+		)
+		${TEST_BACKENDS}
+	)
+"
+
+PATCHES=(
+	"${FILESDIR}/${PN}-3.4.0-doc-nocompress.patch" # bug 830064
+	"${FILESDIR}/${PN}-3.4.0-buildstring.patch"
+
+	"${FILESDIR}/${PN}-5.0.1-cmake-GNUInstallDirs.patch"
+	"${FILESDIR}/${PN}-5.0.1-make-static-libs-optional.patch"
+
+	"${FILESDIR}/${PN}-9999-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch"
+	"${FILESDIR}/${PN}-9999-product_threaded_dont_parallelize.patch"
+)
+
+# TODO should be in cuda.eclass
+cuda_get_host_compiler() {
+	if [[ -n "${NVCC_CCBIN}" ]]; then
+		echo "${NVCC_CCBIN}"
+		return
+	fi
+
+	if [[ -n "${CUDAHOSTCXX}" ]]; then
+		echo "${CUDAHOSTCXX}"
+		return
+	fi
+
+	einfo "Trying to find working CUDA host compiler"
+
+	if ! tc-is-gcc && ! tc-is-clang; then
+		die "$(tc-get-compiler-type) compiler is not supported"
+	fi
+
+	local compiler compiler_type compiler_version
+	local package package_version
+	local -x NVCC_CCBIN
+	local NVCC_CCBIN_default
+
+	compiler_type="$(tc-get-compiler-type)"
+	compiler_version="$("${compiler_type}-major-version")"
+
+	# try the default compiler first
+	NVCC_CCBIN="$(tc-getCXX)"
+	NVCC_CCBIN_default="${NVCC_CCBIN}-${compiler_version}"
+
+	compiler="${NVCC_CCBIN/%-${compiler_version}}"
+
+	# store the package so we can re-use it later
+	package="sys-devel/${compiler_type}"
+	package_version="${package}"
+
+	ebegin "testing ${NVCC_CCBIN_default} (default)"
+
+	while ! nvcc -v -ccbin "${NVCC_CCBIN}" - -x cu <<<"int main(){}" &>> "${T}/cuda_get_host_compiler.log" ; do
+		eend 1
+
+		while true; do
+			# prepare next version
+			if ! package_version="<$(best_version "${package_version}")"; then
+				die "could not find a supported version of ${compiler}"
+			fi
+
+			NVCC_CCBIN="${compiler}-$(ver_cut 1 "${package_version/#<${package}-/}")"
+
+			[[ "${NVCC_CCBIN}" != "${NVCC_CCBIN_default}" ]] && break
+		done
+		ebegin "testing ${NVCC_CCBIN}"
+	done
+	eend $?
+
+	echo "${NVCC_CCBIN}"
+	export NVCC_CCBIN
+}
+
+pkg_pretend() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+}
+
+pkg_setup() {
+	if [[ ${MERGE_TYPE} != binary ]] && use openmp; then
+		tc-check-openmp
+	fi
+
+	if use lapack; then
+		python-any-r1_pkg_setup
+	fi
+
+	if { use test && { use spqr && use cholmod && use blas && use lapack; } || use pastix; } \
+		|| use blas \
+		|| use lapack \
+		; then
+		fortran-2_pkg_setup
+	fi
+
+	if use test && use cuda && use cuda-clang; then
+		llvm-r2_pkg_setup
+	fi
+}
+
+src_unpack() {
+	if [[ ${PV} = *9999* ]] ; then
+		git-r3_src_unpack
+	else
+		unpack "${P}.tar.bz2"
+	fi
+
+	if use test && use lapack; then
+		pushd "${S}/lapack" > /dev/null || die
+		unpack "${PN}-lapack_addons-${LAPACK_ADDONS_PV}.tgz"
+		popd > /dev/null || die
+	fi
+}
+
+src_prepare() {
+	# run patches here as we patch in test/
+	cmake_src_prepare
+
+	if use test && use lapack; then
+		pushd "${S}" > /dev/null || die
+		eapply "${FILESDIR}/${PN}-5.0.1-fix-lapack_testing.py.patch"
+		popd > /dev/null || die
+	fi
+}
+
+src_configure() {
+	if use lapack; then
+		# bug 878987
+		# multiple definition of `cgesdd_'
+		filter-lto
+	fi
+
+	local mycmakeargs=(
+		-DCMAKE_CXX_STANDARD="20"
+		-DCMAKE_POSITION_INDEPENDENT_CODE="yes"
+
+		-DEIGEN_BUILD_TESTING="$(usex test)" # Enable creation of Eigen tests.
+
+		-DEIGEN_BUILD_BLAS="$(usex blas)" # Toggles the building of the Eigen Blas library
+		-DEIGEN_BUILD_LAPACK="$(usex blas "$(usex lapack)")" # Toggles the building of the included Eigen LAPACK library
+
+		-DEIGEN_BUILD_DOC="$(usex doc)" # Enable creation of Eigen documentation
+		-DEIGEN_BUILD_PKGCONFIG="yes" # Build pkg-config .pc file for Eigen
+	)
+
+	append-cxxflags "-DEIGEN_USE_OPENBLAS_BFLOAT16=0"
+
+	if use blas; then
+		mycmakeargs+=(
+			-DBUILD_SHARED_LIBS="yes"
+			-DEIGEN_BUILD_SHARED_LIBS="yes"
+			-DEIGEN_BUILD_STATIC_LIBS="yes"
+			-DEIGEN_INSTALL_STATIC_LIBS="yes"
+		)
+
+		if use lapack; then
+			mycmakeargs+=(
+				-DCMAKE_POLICY_DEFAULT_CMP0148="OLD" # FindPythonInterp
+				-DEIGEN_ENABLE_LAPACK_TESTS="$(usex test)"
+			)
+		fi
+	fi
+
+	if use doc || use test; then
+		mycmakeargs+=(
+			# needs Qt4
+			-DEIGEN_TEST_NOQT="yes" # Disable Qt support in unit tests
+		)
+	fi
+
+	if use doc; then
+		mycmakeargs+=(
+			-DEIGEN_DOC_USE_MATHJAX="$(usex mathjax)" # Use MathJax for rendering math in HTML docs
+			-DEIGEN_INTERNAL_DOCUMENTATION=no # Build internal documentation
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DEIGEN_LEAVE_TEST_IN_ALL_TARGET=yes # Leaves tests in the all target, needed by ctest for automatic building
+
+			# the OpenGL testsuite is extremely brittle, bug #712808
+			-DEIGEN_TEST_OPENGL="$(usex opengl)" # Enable OpenGL support in unit tests
+			-DEIGEN_TEST_OPENMP="$(usex openmp)" # Enable/Disable OpenMP in tests/examples
+
+			-DEIGEN_TEST_EXTERNAL_BLAS="$(usex !blas)" # Use external BLAS library for testsuite
+
+			-DEIGEN_TEST_BUILD_DOCUMENTATION="no" # $(usex doc)" # Test building the doxygen documentation
+
+			-DEIGEN_DEBUG_ASSERTS="$(usex debug)" # Enable advanced debugging of assertions
+			-DEIGEN_SPLIT_LARGE_TESTS="yes" # Split large tests into smaller executables
+
+			-DEIGEN_TEST_CUDA="$(usex cuda)" # Enable CUDA support in unit tests
+			-DEIGEN_TEST_CUDA_CLANG="$(usex cuda "$(usex cuda-clang)")" # Use clang instead of nvcc to compile the CUDA tests
+
+			-DEIGEN_TEST_HIP="$(usex hip)" # Add HIP support.
+
+			# -DEIGEN_TEST_SYCL="$(usex sycl)" # Add Sycl support.
+			# -DEIGEN_SYCL_TRISYCL="no" # Use the triSYCL Sycl implementation (ComputeCPP by default).
+
+			$(cmake_use_find_package adolc Adolc)
+			$(cmake_use_find_package boost Boost)
+			$(cmake_use_find_package cholmod CHOLMOD)
+			# -DDUCCFFT="$(usex ducc)"
+			-DDUCC_ROOT="DUCCFFT"
+			-DDUCCFFT="NOTFOUND"
+			$(cmake_use_find_package fftw FFTW )
+			$(cmake_use_find_package klu KLU)
+			-DCMAKE_DISABLE_FIND_PACKAGE_MPREAL=yes
+			# $(cmake_use_find_package opengl OpenGL) # EIGEN_TEST_OPENGL
+			# $(cmake_use_find_package openmp OpenMP) # EIGEN_TEST_OPENMP
+			$(cmake_use_find_package pastix PASTIX)
+			# prevent pastix_nompi.h lookup it no longer exists, we enforce this via deps
+			-DPASTIX_pastix_nompi.h_INCLUDE_DIRS="FOUND"
+
+			-DPOCKETFFT="$(usex pocketfft)"
+			$(cmake_use_find_package sparsehash GoogleHash)
+			$(cmake_use_find_package spqr SPQR)
+			$(cmake_use_find_package superlu SuperLU)
+			$(cmake_use_find_package umfpack UMFPACK)
+		)
+
+		if use arm; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use arm64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_NEON64="$(usex cpu_flags_arm_neon)"
+			)
+		fi
+
+		if use amd64 || use x86; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_32BIT=no # Force generating 32bit code.
+				# -DEIGEN_TEST_X87=no # Force using X87 instructions. Implies no vectorization.
+				-DEIGEN_TEST_SSE2="$(usex cpu_flags_x86_sse2)"
+				-DEIGEN_TEST_SSE3="$(usex cpu_flags_x86_sse3)"
+				-DEIGEN_TEST_SSSE3="$(usex cpu_flags_x86_ssse3)"
+				-DEIGEN_TEST_FMA="$(usex cpu_flags_x86_fma3)"
+				-DEIGEN_TEST_SSE4_1="$(usex cpu_flags_x86_sse4_1)"
+				-DEIGEN_TEST_SSE4_2="$(usex cpu_flags_x86_sse4_2)"
+				-DEIGEN_TEST_AVX="$(usex cpu_flags_x86_avx)"
+				-DEIGEN_TEST_F16C="$(usex cpu_flags_x86_f16c)"
+				-DEIGEN_TEST_AVX2="$(usex cpu_flags_x86_avx2)"
+				-DEIGEN_TEST_AVX512="$(usex cpu_flags_x86_avx512f)"
+				-DEIGEN_TEST_AVX512DQ="$(usex cpu_flags_x86_avx512dq)"
+			)
+		fi
+
+		if use mips; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_MSA=no # Enable/Disable MSA in tests/examples
+			)
+		fi
+
+		if use ppc || use ppc64; then
+			mycmakeargs+=(
+				-DEIGEN_TEST_ALTIVEC="$(usex cpu_flags_ppc_altivec)"
+				-DEIGEN_TEST_VSX="$(usex cpu_flags_ppc_vsx)"
+			)
+		fi
+
+		if use s390; then
+			mycmakeargs+=(
+				# -DEIGEN_TEST_Z13=no # Enable/Disable S390X(zEC13) ZVECTOR in tests/examples
+				# -DEIGEN_TEST_Z14=no # Enable/Disable S390X(zEC14) ZVECTOR in tests/examples
+			)
+		fi
+
+		if use cuda; then
+			cuda_add_sandbox -w
+
+			if use cuda-clang; then
+				local llvm_prefix
+				llvm_prefix="$(get_llvm_prefix -b)"
+
+				# NVCCFLAGS gets injected into CMAKE_CXX_FLAGS, which means we need to use clang as gcc will fail with
+				# error: unrecognized command-line option
+				if ! tc-is-clang; then
+					export CC="${CHOST}-clang-${LLVM_SLOT}"
+					export CXX="${CHOST}-clang++-${LLVM_SLOT}"
+				fi
+
+				NVCCFLAGS="${NVCCFLAGS:+${NVCCFLAGS} }--libomptarget-nvptx-bc-path=${llvm_prefix}/$(get_libdir)/nvptx64-nvidia-cuda/libomptarget-nvptx.bc"
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CHOST}-clang++-${LLVM_SLOT}"
+				)
+			else
+				cuda_get_host_compiler
+
+				mycmakeargs+=(
+					-DCUDA_HOST_COMPILER="${CUDAHOSTCXX}"
+				)
+				if [[ -v CUDACXX ]]; then
+					mycmakeargs+=(
+						-DCUDA_NVCC_EXECUTABLE="${CUDACXX}"
+						-DCMAKE_POLICY_DEFAULT_CMP0146="OLD" # FindCUDA
+					)
+				fi
+			fi
+
+			if [[ "${CUDA_VERBOSE}" == true ]]; then
+				mycmakeargs+=(
+					-DCUDA_VERBOSE_BUILD="yes"
+				)
+				NVCCFLAGS+=" -v"
+			fi
+
+			if [[ -v CUDAARCHS ]]; then
+				mycmakeargs+=(
+					# TODO this needs to be lowest first for eigen
+					-DEIGEN_CUDA_COMPUTE_ARCH="${CUDAARCHS}"
+				)
+			fi
+
+			# CUDAFLAGS is used by cmake
+			# NVCCFLAGS is used by cuda.eclass
+			mycmakeargs+=(
+				-DEIGEN_CUDA_CXX_FLAGS="${NVCCFLAGS}"
+
+				-DCUDA_USE_STATIC_CUDA_RUNTIME="no"
+			)
+		fi
+
+		if use opengl; then
+			mycmakeargs+=(
+				-DOpenGL_GL_PREFERENCE="GLVND"
+			)
+		fi
+	fi
+
+	cmake_src_configure
+}
+
+src_compile() {
+	local targets=()
+
+	if use blas; then
+		targets+=( blas )
+		if use lapack; then
+			targets+=( lapack )
+		fi
+	fi
+
+	if use test; then
+		targets+=( buildtests )
+
+		if use cuda || use hip; then
+			targets+=( buildtests_gpu )
+		fi
+
+		# tests generate random data, which fails for some seeds
+		# we solve this via test reruns now
+		# export EIGEN_SEED=712808
+	fi
+
+	# we add doc last to capture results for buildtests
+	if use doc; then
+		targets+=( doc )
+	fi
+
+	if [[ -n "${targets[*]}" ]]; then
+		cmake_src_compile "${targets[@]}"
+	fi
+}
+
+src_test() {
+	local CMAKE_SKIP_TESTS=(
+		"^ref_8$"
+	)
+
+	if use cholmod && use blas && use lapack; then
+		CMAKE_SKIP_TESTS+=(
+		"^cholmod_support_21$"
+		"^cholmod_support_22$"
+		)
+	fi
+
+	if use cuda; then
+		cuda_add_sandbox -w
+	fi
+
+	if use klu && use blas; then
+		CMAKE_SKIP_TESTS+=(
+			"^klu_support_1$"
+			"^klu_support_2$"
+		)
+	fi
+
+	if use lapack; then
+		CMAKE_SKIP_TESTS+=(
+			"^LAPACK-xlintsts_stest_in$"
+			"^LAPACK-xeigtsts_sep_in$"
+			"^LAPACK-xeigtsts_svd_in$"
+			"^LAPACK-xlintstd_dtest_in$"
+			"^LAPACK-xeigtstd_sep_in$"
+			"^LAPACK-xeigtstd_svd_in$"
+			"^LAPACK-xlintstc_ctest_in$"
+			"^LAPACK-xeigtstc_svd_in$"
+		)
+	fi
+
+	local myctestargs=(
+		-j1 # otherwise breaks due to cmake reruns
+		--repeat until-pass:50
+	)
+
+	if use opengl; then
+		virtx \
+			cmake_src_test
+	else
+		cmake_src_test
+	fi
+}
+
+src_install() {
+	local DOCS=()
+	cmake_src_install
+
+	if use doc; then
+		pushd "${BUILD_DIR}/doc" > /dev/null || die
+		dodoc -r html
+		popd > /dev/null || die
+	fi
+}
diff --git a/dev-cpp/eigen/files/eigen-3.3.9-max-macro.patch b/dev-cpp/eigen/files/eigen-3.3.9-max-macro.patch
new file mode 100644
index 000000000000..c5fdc2ed582c
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.3.9-max-macro.patch
@@ -0,0 +1,17 @@
+--- a/unsupported/test/forward_adolc.cpp
++++ b/unsupported/test/forward_adolc.cpp
+@@ -7,12 +7,13 @@
+ // Public License v. 2.0. If a copy of the MPL was not distributed
+ // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ 
+-#include "main.h"
+ #include <Eigen/Dense>
+ 
+ #define NUMBER_DIRECTIONS 16
+ #include <unsupported/Eigen/AdolcForward>
+ 
++#include "main.h"
++
+ template<typename Vector>
+ EIGEN_DONT_INLINE typename Vector::Scalar foo(const Vector& p)
+ {
diff --git a/dev-cpp/eigen/files/eigen-3.4.0-buildstring.patch b/dev-cpp/eigen/files/eigen-3.4.0-buildstring.patch
new file mode 100644
index 000000000000..8e9b98fbd8bb
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.4.0-buildstring.patch
@@ -0,0 +1,25 @@
+--- a/cmake/EigenTesting.cmake
++++ b/cmake/EigenTesting.cmake
+@@ -559,14 +559,22 @@ macro(ei_get_cxxflags VAR)
+     set(${VAR} VSX)
+   elseif(EIGEN_TEST_ALTIVEC)
+     set(${VAR} ALVEC)
++  elseif(EIGEN_TEST_AVX512DQ)
++    set(${VAR} AVX512DQ)
++  elseif(EIGEN_TEST_AVX512)
++    set(${VAR} AVX512)
++  elseif(EIGEN_TEST_AVX2)
++    set(${VAR} AVX2)
+   elseif(EIGEN_TEST_FMA)
+     set(${VAR} FMA)
++  elseif(EIGEN_TEST_F16C)
++    set(${VAR} F16C)
+   elseif(EIGEN_TEST_AVX)
+     set(${VAR} AVX)
+   elseif(EIGEN_TEST_SSE4_2)
+     set(${VAR} SSE42)
+   elseif(EIGEN_TEST_SSE4_1)
+     set(${VAR} SSE41)
+   elseif(EIGEN_TEST_SSSE3)
+     set(${VAR} SSSE3)
+   elseif(EIGEN_TEST_SSE3)
diff --git a/dev-cpp/eigen/files/eigen-3.4.0-c++-20.patch b/dev-cpp/eigen/files/eigen-3.4.0-c++-20.patch
new file mode 100644
index 000000000000..39eef7dc0c0f
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.4.0-c++-20.patch
@@ -0,0 +1,30 @@
+From: Nicholas Vinson <nvinson234@gmail.com>
+Date: Mon, 15 Dec 2025 20:37:04 -0500
+
+--- a/Eigen/src/Eigenvalues/ComplexSchur.h
++++ b/Eigen/src/Eigenvalues/ComplexSchur.h
+@@ -277,7 +277,8 @@
+   using std::abs;
+   if ((iter == 10 || iter == 20) && iu > 1) {
+     // exceptional shift, taken from http://www.netlib.org/eispack/comqr.f
+-    return abs(numext::real(m_matT.coeff(iu,iu-1))) + abs(numext::real(m_matT.coeff(iu-1,iu-2)));
++    return ComplexSchur<MatrixType>::ComplexScalar(
++        abs(numext::real(m_matT.coeff(iu, iu - 1))) + abs(numext::real(m_matT.coeff(iu - 1, iu - 2))));
+   }
+ 
+   // compute the shift as one of the eigenvalues of t, the 2x2
+--- a/unsupported/Eigen/src/MatrixFunctions/MatrixFunction.h
++++ b/unsupported/Eigen/src/MatrixFunctions/MatrixFunction.h
+@@ -86,8 +86,8 @@
+         for (Index i = 0; i < rows; i++)
+           mx = (std::max)(mx, std::abs(m_f(Ashifted(i, i) + avgEival, static_cast<int>(s + r))));
+         if (r != 0)
+           rfactorial *= RealScalar(r);
+-        delta = (std::max)(delta, mx / rfactorial);
++        delta = (std::max)(delta, RealScalar(mx / rfactorial));
+       }
+       const RealScalar P_norm = P.cwiseAbs().rowwise().sum().maxCoeff();
+       if (mu * delta * P_norm < NumTraits<Scalar>::epsilon() * F_norm)  // series converged
+-- 
+2.52.0
+
diff --git a/dev-cpp/eigen/files/eigen-3.4.0-cxxstandard.patch b/dev-cpp/eigen/files/eigen-3.4.0-cxxstandard.patch
new file mode 100644
index 000000000000..826aa78d05aa
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.4.0-cxxstandard.patch
@@ -0,0 +1,108 @@
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -74,19 +74,9 @@ macro(ei_add_cxx_compiler_flag FLAG)
+   endif()
+ endmacro()
+ 
+-check_cxx_compiler_flag("-std=c++11" EIGEN_COMPILER_SUPPORT_CPP11)
+-
+-if(EIGEN_TEST_CXX11)
+-  set(CMAKE_CXX_STANDARD 11)
+-  set(CMAKE_CXX_EXTENSIONS OFF)
+-  if(EIGEN_COMPILER_SUPPORT_CPP11)
+-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+-  endif()
+-else()
+-  #set(CMAKE_CXX_STANDARD 03)
+-  #set(CMAKE_CXX_EXTENSIONS OFF)
+-  ei_add_cxx_compiler_flag("-std=c++03")
+-endif()
++set(CMAKE_CXX_STANDARD 14)
++set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
++set(CMAKE_CXX_EXTENSIONS OFF)
+ 
+ # Determine if we should build shared libraries on this platform.
+ get_cmake_property(EIGEN_BUILD_SHARED_LIBS TARGET_SUPPORTS_SHARED_LIBS)
+@@ -157,7 +157,6 @@ if(NOT MSVC)
+   ei_add_cxx_compiler_flag("-Wshorten-64-to-32")
+   ei_add_cxx_compiler_flag("-Wlogical-op")
+   ei_add_cxx_compiler_flag("-Wenum-conversion")
+-  ei_add_cxx_compiler_flag("-Wc++11-extensions")
+   ei_add_cxx_compiler_flag("-Wdouble-promotion")
+ #  ei_add_cxx_compiler_flag("-Wconversion")
+
+--- a/Eigen/src/Core/util/Macros.h
++++ b/Eigen/src/Core/util/Macros.h
+@@ -37,7 +37,7 @@
+ // Expected values are 03, 11, 14, 17, etc.
+ // By default, let's use an arbitrarily large C++ version.
+ #ifndef EIGEN_MAX_CPP_VER
+-#define EIGEN_MAX_CPP_VER 99
++#define EIGEN_MAX_CPP_VER 14
+ #endif
+ 
+ /** Allows to disable some optimizations which might affect the accuracy of the result.
+--- a/doc/examples/CMakeLists.txt
++++ b/doc/examples/CMakeLists.txt
+@@ -14,7 +14,3 @@ foreach(example_src ${examples_SRCS})
+   )
+   add_dependencies(all_examples ${example})
+ endforeach()
+-
+-if(EIGEN_COMPILER_SUPPORT_CPP11)
+-ei_add_target_property(nullary_indexing COMPILE_FLAGS "-std=c++11")
+-endif()
+\ No newline at end of file
+diff --git a/doc/snippets/CMakeLists.txt b/doc/snippets/CMakeLists.txt
+index 65f195a..4cb18c8 100644
+--- a/doc/snippets/CMakeLists.txt
++++ b/doc/snippets/CMakeLists.txt
+@@ -15,9 +15,6 @@ foreach(snippet_src ${snippets_SRCS})
+     if(EIGEN_STANDARD_LIBRARIES_TO_LINK_TO)
+       target_link_libraries(${compile_snippet_target} ${EIGEN_STANDARD_LIBRARIES_TO_LINK_TO})
+     endif()
+-    if(${snippet_src} MATCHES "cxx11")
+-      set_target_properties(${compile_snippet_target} PROPERTIES COMPILE_FLAGS "-std=c++11")
+-    endif()
+     if(${snippet_src} MATCHES "deprecated")
+       set_target_properties(${compile_snippet_target} PROPERTIES COMPILE_FLAGS "-DEIGEN_NO_DEPRECATED_WARNING")
+     endif()
+--- a/test/CMakeLists.txt
++++ b/test/CMakeLists.txt
+@@ -399,7 +399,6 @@ if(CUDA_FOUND)
+     set(CUDA_NVCC_FLAGS "-ccbin ${CMAKE_C_COMPILER}" CACHE STRING "nvcc flags" FORCE)
+   endif()
+   if(EIGEN_TEST_CUDA_CLANG)
+-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+     string(APPEND CMAKE_CXX_FLAGS " --cuda-path=${CUDA_TOOLKIT_ROOT_DIR}")
+     foreach(GPU IN LISTS EIGEN_CUDA_COMPUTE_ARCH)
+       string(APPEND CMAKE_CXX_FLAGS " --cuda-gpu-arch=sm_${GPU}")
+--- a/unsupported/test/CMakeLists.txt
++++ b/unsupported/test/CMakeLists.txt
+@@ -59,7 +59,7 @@ find_package(MPREAL)
+ if(MPREAL_FOUND AND EIGEN_COMPILER_SUPPORT_CPP11)
+   ei_add_property(EIGEN_TESTED_BACKENDS "MPFR C++, ")
+   include_directories(${MPREAL_INCLUDES})
+-  ei_add_test(mpreal_support "-std=c++11" "${MPREAL_LIBRARIES}" )
++  ei_add_test(mpreal_support "-std=c++14" "${MPREAL_LIBRARIES}" )
+ else()
+   ei_add_property(EIGEN_MISSING_BACKENDS "MPFR C++, ")
+ endif()
+@@ -308,7 +308,6 @@ if(CUDA_FOUND AND EIGEN_TEST_CUDA)
+     set(CUDA_NVCC_FLAGS "-ccbin ${CMAKE_C_COMPILER}" CACHE STRING "nvcc flags" FORCE)
+   endif()
+   if(EIGEN_TEST_CUDA_CLANG)
+-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+     string(APPEND CMAKE_CXX_FLAGS " --cuda-path=${CUDA_TOOLKIT_ROOT_DIR}")
+     foreach(ARCH IN LISTS EIGEN_CUDA_COMPUTE_ARCH)
+         string(APPEND CMAKE_CXX_FLAGS " --cuda-gpu-arch=sm_${ARCH}")
+--- a/doc/special_examples/CMakeLists.txt
++++ b/doc/special_examples/CMakeLists.txt
+@@ -23,7 +23,6 @@ if(EIGEN_COMPILER_SUPPORT_CPP11)
+   add_executable(random_cpp11 random_cpp11.cpp)
+   target_link_libraries(random_cpp11 ${EIGEN_STANDARD_LIBRARIES_TO_LINK_TO})
+   add_dependencies(all_examples random_cpp11)
+-  ei_add_target_property(random_cpp11 COMPILE_FLAGS "-std=c++11")
+
+   add_custom_command(
+     TARGET random_cpp11
diff --git a/dev-cpp/eigen/files/eigen-3.4.0-doc-nocompress.patch b/dev-cpp/eigen/files/eigen-3.4.0-doc-nocompress.patch
new file mode 100644
index 000000000000..b9c252ebb09c
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.4.0-doc-nocompress.patch
@@ -0,0 +1,15 @@
+--- a/doc/CMakeLists.txt
++++ b/doc/CMakeLists.txt
+@@ -112,11 +112,7 @@
+   COMMAND doxygen
+   COMMAND doxygen Doxyfile-unsupported
+   COMMAND ${CMAKE_COMMAND} -E copy ${Eigen_BINARY_DIR}/doc/html/group__TopicUnalignedArrayAssert.html ${Eigen_BINARY_DIR}/doc/html/TopicUnalignedArrayAssert.html
+-  COMMAND ${CMAKE_COMMAND} -E rename html eigen-doc
+-  COMMAND ${CMAKE_COMMAND} -E remove eigen-doc/eigen-doc.tgz eigen-doc/unsupported/_formulas.log eigen-doc/_formulas.log
+-  COMMAND ${CMAKE_COMMAND} -E tar cfz eigen-doc.tgz eigen-doc
+-  COMMAND ${CMAKE_COMMAND} -E rename eigen-doc.tgz eigen-doc/eigen-doc.tgz
+-  COMMAND ${CMAKE_COMMAND} -E rename eigen-doc html
++  COMMAND ${CMAKE_COMMAND} -E remove html/unsupported/_formulas.log html/_formulas.log
+   WORKING_DIRECTORY ${Eigen_BINARY_DIR}/doc)
+ 
+ add_dependencies(doc doc-eigen-prerequisites doc-unsupported-prerequisites)
diff --git a/dev-cpp/eigen/files/eigen-3.4.0-noansi.patch b/dev-cpp/eigen/files/eigen-3.4.0-noansi.patch
new file mode 100644
index 000000000000..c0ce44445c1d
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.4.0-noansi.patch
@@ -0,0 +1,18 @@
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -184,6 +184,7 @@ if(NOT MSVC)
+   ei_add_cxx_compiler_flag("-wd2304")                   # disable ICC's "warning #2304: non-explicit constructor with single argument may cause implicit type conversion" produced by -Wnon-virtual-dtor
+ 
+ 
++  if(NOT EIGEN_TEST_CXX11)
+   # The -ansi flag must be added last, otherwise it is also used as a linker flag by check_cxx_compiler_flag making it fails
+   # Moreover we should not set both -strict-ansi and -ansi
+   check_cxx_compiler_flag("-strict-ansi" COMPILER_SUPPORT_STRICTANSI)
+@@ -194,6 +195,7 @@ if(NOT MSVC)
+   else()
+     ei_add_cxx_compiler_flag("-ansi")
+   endif()
++  endif()
+ 
+   if(ANDROID_NDK)
+     ei_add_cxx_compiler_flag("-pie")
diff --git a/dev-cpp/eigen/files/eigen-3.4.0-ppc-no-vsx.patch b/dev-cpp/eigen/files/eigen-3.4.0-ppc-no-vsx.patch
new file mode 100644
index 000000000000..7cfeaaf129ff
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.4.0-ppc-no-vsx.patch
@@ -0,0 +1,195 @@
+https://gitlab.com/libeigen/eigen/-/merge_requests/1028
+https://bugs.gentoo.org/936107
+--- a/Eigen/Core
++++ b/Eigen/Core
+@@ -346,7 +346,7 @@
+ #include "src/Core/CoreIterators.h"
+ #include "src/Core/ConditionEstimator.h"
+ 
+-#if defined(EIGEN_VECTORIZE_ALTIVEC) || defined(EIGEN_VECTORIZE_VSX)
++#if defined(EIGEN_VECTORIZE_VSX)
+   #include "src/Core/arch/AltiVec/MatrixProduct.h"
+ #elif defined EIGEN_VECTORIZE_NEON
+   #include "src/Core/arch/NEON/GeneralBlockPanelKernel.h"
+--- a/Eigen/src/Core/arch/AltiVec/Complex.h
++++ b/Eigen/src/Core/arch/AltiVec/Complex.h
+@@ -100,6 +100,7 @@
+     HasAbs2   = 0,
+     HasMin    = 0,
+     HasMax    = 0,
++    HasSqrt   = 1,
+ #ifdef __VSX__
+     HasBlend  = 1,
+ #endif
+@@ -320,6 +321,7 @@
+     HasAbs2   = 0,
+     HasMin    = 0,
+     HasMax    = 0,
++    HasSqrt   = 1,
+     HasSetLinear = 0
+   };
+ };
+--- a/Eigen/src/Core/arch/AltiVec/MathFunctions.h
++++ b/Eigen/src/Core/arch/AltiVec/MathFunctions.h
+@@ -40,16 +40,14 @@
+   return pcos_float(_x);
+ }
+ 
++#ifdef __VSX__
+ #ifndef EIGEN_COMP_CLANG
+ template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED
+ Packet4f prsqrt<Packet4f>(const Packet4f& x)
+ {
+   return  vec_rsqrt(x);
+ }
+-#endif
+ 
+-#ifdef __VSX__
+-#ifndef EIGEN_COMP_CLANG
+ template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED
+ Packet2d prsqrt<Packet2d>(const Packet2d& x)
+ {
+@@ -74,6 +72,26 @@
+ {
+   return pexp_double(_x);
+ }
++
++template<> EIGEN_STRONG_INLINE Packet8bf psqrt<Packet8bf> (const Packet8bf& a){
++  BF16_TO_F32_UNARY_OP_WRAPPER(psqrt<Packet4f>, a);
++}
++
++#ifndef EIGEN_COMP_CLANG
++template<> EIGEN_STRONG_INLINE Packet8bf prsqrt<Packet8bf> (const Packet8bf& a){
++  BF16_TO_F32_UNARY_OP_WRAPPER(prsqrt<Packet4f>, a);
++}
++#endif
++#else
++template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
++Packet4f psqrt<Packet4f>(const Packet4f& x)
++{
++  Packet4f a;
++  for (Index i = 0; i < packet_traits<float>::size; i++) {
++    a[i] = numext::sqrt(x[i]);
++  }
++  return a;
++}
+ #endif
+ 
+ // Hyperbolic Tangent function.
+--- a/Eigen/src/Core/arch/AltiVec/PacketMath.h
++++ b/Eigen/src/Core/arch/AltiVec/PacketMath.h
+@@ -175,16 +175,19 @@
+ #else
+     HasRsqrt = 0,
+ #endif
++    HasTanh = EIGEN_FAST_MATH,
++    HasErf = EIGEN_FAST_MATH,
++    HasRint = 1,
+ #else
+     HasSqrt = 0,
+     HasRsqrt = 0,
+-    HasTanh = EIGEN_FAST_MATH,
+-    HasErf = EIGEN_FAST_MATH,
++    HasTanh = 0,
++    HasErf = 0,
++    HasRint = 0,
+ #endif
+     HasRound = 1,
+     HasFloor = 1,
+     HasCeil = 1,
+-    HasRint = 1,
+     HasNegate = 1,
+     HasBlend = 1
+   };
+@@ -217,16 +220,17 @@
+ #else
+     HasRsqrt = 0,
+ #endif
++    HasRint = 1,
+ #else
+     HasSqrt = 0,
+     HasRsqrt = 0,
+-    HasTanh = EIGEN_FAST_MATH,
+-    HasErf = EIGEN_FAST_MATH,
++    HasRint = 0,
+ #endif
++    HasTanh = 0,
++    HasErf = 0,
+     HasRound = 1,
+     HasFloor = 1,
+     HasCeil = 1,
+-    HasRint = 1,
+     HasNegate = 1,
+     HasBlend = 1
+   };
+@@ -872,19 +876,29 @@
+   return vec_nor(c,c);
+ }
+ 
++#ifdef __VSX__
+ template<> EIGEN_STRONG_INLINE Packet4i pcmp_le(const Packet4i& a, const Packet4i& b) { return reinterpret_cast<Packet4i>(vec_cmple(a,b)); }
++#endif
+ template<> EIGEN_STRONG_INLINE Packet4i pcmp_lt(const Packet4i& a, const Packet4i& b) { return reinterpret_cast<Packet4i>(vec_cmplt(a,b)); }
+ template<> EIGEN_STRONG_INLINE Packet4i pcmp_eq(const Packet4i& a, const Packet4i& b) { return reinterpret_cast<Packet4i>(vec_cmpeq(a,b)); }
++#ifdef __VSX__
+ template<> EIGEN_STRONG_INLINE Packet8s pcmp_le(const Packet8s& a, const Packet8s& b) { return reinterpret_cast<Packet8s>(vec_cmple(a,b)); }
++#endif
+ template<> EIGEN_STRONG_INLINE Packet8s pcmp_lt(const Packet8s& a, const Packet8s& b) { return reinterpret_cast<Packet8s>(vec_cmplt(a,b)); }
+ template<> EIGEN_STRONG_INLINE Packet8s pcmp_eq(const Packet8s& a, const Packet8s& b) { return reinterpret_cast<Packet8s>(vec_cmpeq(a,b)); }
++#ifdef __VSX__
+ template<> EIGEN_STRONG_INLINE Packet8us pcmp_le(const Packet8us& a, const Packet8us& b) { return reinterpret_cast<Packet8us>(vec_cmple(a,b)); }
++#endif
+ template<> EIGEN_STRONG_INLINE Packet8us pcmp_lt(const Packet8us& a, const Packet8us& b) { return reinterpret_cast<Packet8us>(vec_cmplt(a,b)); }
+ template<> EIGEN_STRONG_INLINE Packet8us pcmp_eq(const Packet8us& a, const Packet8us& b) { return reinterpret_cast<Packet8us>(vec_cmpeq(a,b)); }
++#ifdef __VSX__
+ template<> EIGEN_STRONG_INLINE Packet16c pcmp_le(const Packet16c& a, const Packet16c& b) { return reinterpret_cast<Packet16c>(vec_cmple(a,b)); }
++#endif
+ template<> EIGEN_STRONG_INLINE Packet16c pcmp_lt(const Packet16c& a, const Packet16c& b) { return reinterpret_cast<Packet16c>(vec_cmplt(a,b)); }
+ template<> EIGEN_STRONG_INLINE Packet16c pcmp_eq(const Packet16c& a, const Packet16c& b) { return reinterpret_cast<Packet16c>(vec_cmpeq(a,b)); }
++#ifdef __VSX__
+ template<> EIGEN_STRONG_INLINE Packet16uc pcmp_le(const Packet16uc& a, const Packet16uc& b) { return reinterpret_cast<Packet16uc>(vec_cmple(a,b)); }
++#endif
+ template<> EIGEN_STRONG_INLINE Packet16uc pcmp_lt(const Packet16uc& a, const Packet16uc& b) { return reinterpret_cast<Packet16uc>(vec_cmplt(a,b)); }
+ template<> EIGEN_STRONG_INLINE Packet16uc pcmp_eq(const Packet16uc& a, const Packet16uc& b) { return reinterpret_cast<Packet16uc>(vec_cmpeq(a,b)); }
+ 
+@@ -937,6 +951,7 @@
+ }
+ template<> EIGEN_STRONG_INLINE Packet4f pceil<Packet4f>(const  Packet4f& a) { return vec_ceil(a); }
+ template<> EIGEN_STRONG_INLINE Packet4f pfloor<Packet4f>(const Packet4f& a) { return vec_floor(a); }
++#ifdef __VSX__
+ template<> EIGEN_STRONG_INLINE Packet4f print<Packet4f>(const Packet4f& a)
+ {
+     Packet4f res;
+@@ -947,6 +962,7 @@
+ 
+     return res;
+ }
++#endif
+ 
+ template<typename Packet> EIGEN_STRONG_INLINE Packet ploadu_common(const __UNPACK_TYPE__(Packet)* from)
+ {
+@@ -1341,12 +1357,6 @@
+   BF16_TO_F32_BINARY_OP_WRAPPER(psub<Packet4f>, a, b);
+ }
+ 
+-template<> EIGEN_STRONG_INLINE Packet8bf psqrt<Packet8bf> (const Packet8bf& a){
+-  BF16_TO_F32_UNARY_OP_WRAPPER(vec_sqrt, a);
+-}
+-template<> EIGEN_STRONG_INLINE Packet8bf prsqrt<Packet8bf> (const Packet8bf& a){
+-  BF16_TO_F32_UNARY_OP_WRAPPER(prsqrt<Packet4f>, a);
+-}
+ template<> EIGEN_STRONG_INLINE Packet8bf pexp<Packet8bf> (const Packet8bf& a){
+   BF16_TO_F32_UNARY_OP_WRAPPER(pexp_float, a);
+ }
+@@ -1390,9 +1400,11 @@
+ template<> EIGEN_STRONG_INLINE Packet8bf pround<Packet8bf> (const Packet8bf& a){
+   BF16_TO_F32_UNARY_OP_WRAPPER(pround<Packet4f>, a);
+ }
++#ifdef __VSX__
+ template<> EIGEN_STRONG_INLINE Packet8bf print<Packet8bf> (const Packet8bf& a){
+   BF16_TO_F32_UNARY_OP_WRAPPER(print<Packet4f>, a);
+ }
++#endif
+ template<> EIGEN_STRONG_INLINE Packet8bf pmadd(const Packet8bf& a, const Packet8bf& b, const Packet8bf& c) {
+   Packet4f a_even = Bf16ToF32Even(a);
+   Packet4f a_odd = Bf16ToF32Odd(a);
diff --git a/dev-cpp/eigen/files/eigen-3.4.1-bug1213-link-with-Eigen3-Eigen.patch b/dev-cpp/eigen/files/eigen-3.4.1-bug1213-link-with-Eigen3-Eigen.patch
new file mode 100644
index 000000000000..9ced714f0c51
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.4.1-bug1213-link-with-Eigen3-Eigen.patch
@@ -0,0 +1,25 @@
+From 470c47b3b8309cb71cf48146e56744bd2630827a Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Sat, 28 Feb 2026 23:16:55 +0100
+Subject: [PATCH] bug1213: link with Eigen3::Eigen
+
+Doesn't find Eigen/Core otherwise.
+---
+ test/CMakeLists.txt | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
+index f503efc..360f989 100644
+--- a/test/CMakeLists.txt
++++ b/test/CMakeLists.txt
+@@ -299,6 +299,7 @@ if(EIGEN_TEST_CXX11)
+ endif()
+ 
+ add_executable(bug1213 bug1213.cpp bug1213_main.cpp)
++target_link_libraries(bug1213 Eigen3::Eigen)
+ 
+ check_cxx_compiler_flag("-ffast-math" COMPILER_SUPPORT_FASTMATH)
+ if(COMPILER_SUPPORT_FASTMATH)
+-- 
+2.53.0
+
diff --git a/dev-cpp/eigen/files/eigen-3.4.1-cxxstandard-17.patch b/dev-cpp/eigen/files/eigen-3.4.1-cxxstandard-17.patch
new file mode 100644
index 000000000000..720898bdd11c
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-3.4.1-cxxstandard-17.patch
@@ -0,0 +1,72 @@
+From cd8bb671321b5163c21f84689f929b671ed68750 Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Mon, 20 Oct 2025 21:26:47 +0200
+Subject: [PATCH] cxx standard 17
+
+Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 80d36b991..8106bb264 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -330,11 +330,8 @@ if (EIGEN_BUILD_TESTING)
+ 
+   option(EIGEN_TEST_CXX11 "Enable testing with C++11 and C++11 features (e.g. Tensor module)." ${EIGEN_COMPILER_SUPPORT_CPP11})
+   if(EIGEN_TEST_CXX11)
+-    set(CMAKE_CXX_STANDARD 11)
++    set(CMAKE_CXX_STANDARD 17)
+     set(CMAKE_CXX_EXTENSIONS OFF)
+-    if(EIGEN_COMPILER_SUPPORT_CPP11)
+-      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+-    endif()
+   else()
+     ei_add_cxx_compiler_flag("-std=c++03")
+   endif()
+@@ -373,7 +370,7 @@ if (EIGEN_BUILD_TESTING)
+     ei_add_cxx_compiler_flag("-Wshorten-64-to-32")
+     ei_add_cxx_compiler_flag("-Wlogical-op")
+     ei_add_cxx_compiler_flag("-Wenum-conversion")
+-    ei_add_cxx_compiler_flag("-Wc++11-extensions")
++    # ei_add_cxx_compiler_flag("-Wc++11-extensions")
+     ei_add_cxx_compiler_flag("-Wdouble-promotion")
+     # ei_add_cxx_compiler_flag("-Wconversion")
+     ei_add_cxx_compiler_flag("-Wshadow")
+diff --git a/doc/special_examples/CMakeLists.txt b/doc/special_examples/CMakeLists.txt
+index a0267a512..d7fc80976 100644
+--- a/doc/special_examples/CMakeLists.txt
++++ b/doc/special_examples/CMakeLists.txt
+@@ -23,7 +23,6 @@ if(EIGEN_COMPILER_SUPPORT_CPP11)
+   add_executable(random_cpp11 random_cpp11.cpp)
+   target_link_libraries(random_cpp11 ${EIGEN_STANDARD_LIBRARIES_TO_LINK_TO} Eigen3::Eigen)
+   add_dependencies(all_examples random_cpp11)
+-  target_compile_options(random_cpp11 PRIVATE "-std=c++11")
+ 
+   add_custom_command(
+     TARGET random_cpp11
+diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
+index 7ce260e0e..f503efc5d 100644
+--- a/test/CMakeLists.txt
++++ b/test/CMakeLists.txt
+@@ -386,7 +386,6 @@ if(CUDA_FOUND AND EIGEN_TEST_CUDA)
+   string(REPLACE "-fno-check-new" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+ 
+   if(EIGEN_TEST_CUDA_CLANG)
+-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+     string(APPEND CMAKE_CXX_FLAGS " --cuda-path=${CUDA_TOOLKIT_ROOT_DIR}")
+     foreach(GPU IN LISTS EIGEN_CUDA_COMPUTE_ARCH)
+       string(APPEND CMAKE_CXX_FLAGS " --cuda-gpu-arch=sm_${GPU}")
+diff --git a/unsupported/test/CMakeLists.txt b/unsupported/test/CMakeLists.txt
+index 1d5e9b174..cf394de86 100644
+--- a/unsupported/test/CMakeLists.txt
++++ b/unsupported/test/CMakeLists.txt
+@@ -227,7 +227,6 @@ if(CUDA_FOUND AND EIGEN_TEST_CUDA)
+   string(REPLACE "-ansi" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+ 
+   if(EIGEN_TEST_CUDA_CLANG)
+-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+     string(APPEND CMAKE_CXX_FLAGS " --cuda-path=${CUDA_TOOLKIT_ROOT_DIR}")
+     foreach(ARCH IN LISTS EIGEN_CUDA_COMPUTE_ARCH)
+         string(APPEND CMAKE_CXX_FLAGS " --cuda-gpu-arch=sm_${ARCH}")
+-- 
+2.51.1
+
diff --git a/dev-cpp/eigen/files/eigen-5.0.0-doxygen-1.14.patch b/dev-cpp/eigen/files/eigen-5.0.0-doxygen-1.14.patch
new file mode 100644
index 000000000000..89e049368022
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-5.0.0-doxygen-1.14.patch
@@ -0,0 +1,136 @@
+From cf458c66ee01802d5023fcab78412583b5c73574 Mon Sep 17 00:00:00 2001
+From: Guilhem Saurel <guilhem.saurel@laas.fr>
+Date: Tue, 16 Dec 2025 09:40:05 +0100
+Subject: [PATCH 1/4] doc: add and use \anchor Eigen_placeholders_lastN
+
+fix for Doxygen >= 1.14:
+```
+doc/Manual.dox:177: error: unable to resolve link to 'Eigen::placeholders::lastN(SizeType)' for \link command
+doc/Manual.dox:178: error: unable to resolve link to 'Eigen::placeholders::lastN(SizeType,IncrType)' for \link command
+```
+---
+ Eigen/src/Core/ArithmeticSequence.h | 2 +-
+ doc/TutorialSlicingIndexing.dox     | 3 +--
+ 2 files changed, 2 insertions(+), 3 deletions(-)
+
+diff --git a/Eigen/src/Core/ArithmeticSequence.h b/Eigen/src/Core/ArithmeticSequence.h
+index ae6373dda..41617713f 100644
+--- a/Eigen/src/Core/ArithmeticSequence.h
++++ b/Eigen/src/Core/ArithmeticSequence.h
+@@ -182,7 +182,7 @@ namespace placeholders {
+  * \returns a symbolic ArithmeticSequence representing the last \a size elements with increment \a incr.
+  *
+  * It is a shortcut for: \code seqN(last-(size-fix<1>)*incr, size, incr) \endcode
+- *
++ * \anchor Eigen_placeholders_lastN
+  * \sa lastN(SizeType), seqN(FirstType,SizeType), seq(FirstType,LastType,IncrType) */
+ template <typename SizeType, typename IncrType>
+ auto lastN(SizeType size, IncrType incr)
+diff --git a/doc/TutorialSlicingIndexing.dox b/doc/TutorialSlicingIndexing.dox
+index 6ebaa2d6d..a1b00dfc4 100644
+--- a/doc/TutorialSlicingIndexing.dox
++++ b/doc/TutorialSlicingIndexing.dox
+@@ -114,8 +114,7 @@ Here are some examples for a 2D array/matrix \c A and a 1D array/vector \c v.
+ 
+ As seen in the last example, referencing the <i> last n </i> elements (or rows/columns) is a bit cumbersome to write.
+ This becomes even more tricky and error prone with a non-default increment.
+-Here comes \link Eigen::placeholders::lastN(SizeType) Eigen::placeholders::lastN(size) \endlink, and
+-\link Eigen::placeholders::lastN(SizeType,IncrType) Eigen::placeholders::lastN(size,incr) \endlink:
++Here comes \ref Eigen_placeholders_lastN :
+ 
+ <table class="manual">
+ <tr>
+-- 
+GitLab
+
+
+From 6be98c166c86a2360177bad9cdccc55ac1ceed7b Mon Sep 17 00:00:00 2001
+From: Guilhem Saurel <guilhem.saurel@laas.fr>
+Date: Tue, 16 Dec 2025 10:13:56 +0100
+Subject: [PATCH 2/4] doc: fix html
+
+fix for Doxygen >= 1.14:
+```
+doc/Manual.dox:656: error: expected <tr> or </table> tag but found token TK_HTMLTAG instead!
+```
+---
+ doc/QuickReference.dox | 1 -
+ 1 file changed, 1 deletion(-)
+
+diff --git a/doc/QuickReference.dox b/doc/QuickReference.dox
+index 1fb000fdc..4aece902c 100644
+--- a/doc/QuickReference.dox
++++ b/doc/QuickReference.dox
+@@ -551,7 +551,6 @@ Read-write access to sub-vectors:
+ <tr>
+ <th>Default versions</th>
+ <th>Optimized versions when the size \n is known at compile time</th></tr>
+-<th></th>
+ 
+ <tr><td>\code vec1.head(n)\endcode</td><td>\code vec1.head<n>()\endcode</td><td>the first \c n coeffs </td></tr>
+ <tr><td>\code vec1.tail(n)\endcode</td><td>\code vec1.tail<n>()\endcode</td><td>the last \c n coeffs </td></tr>
+-- 
+GitLab
+
+
+From ac5d00609f14b7402f1fe8274e4d5db3c61f091e Mon Sep 17 00:00:00 2001
+From: Guilhem Saurel <guilhem.saurel@laas.fr>
+Date: Tue, 16 Dec 2025 10:37:35 +0100
+Subject: [PATCH 3/4] doc: typo
+
+fix for doxygen 1.15:
+```
+doc/UnalignedArrayAssert.dox:134: error: Reached end of file while still searching closing '`' of a verbatim block starting at line 117
+doc/UnalignedArrayAssert.dox:134: error: Reached end of file while still inside a (nested) comment. Nesting level 1 (possible line reference(s): 3)
+```
+---
+ doc/UnalignedArrayAssert.dox | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/doc/UnalignedArrayAssert.dox b/doc/UnalignedArrayAssert.dox
+index ca674a267..0ed6f8835 100644
+--- a/doc/UnalignedArrayAssert.dox
++++ b/doc/UnalignedArrayAssert.dox
+@@ -7,7 +7,7 @@ Hello! You are seeing this webpage because your program terminated on an asserti
+ my_program: path/to/eigen/Eigen/src/Core/DenseStorage.h:44:
+ Eigen::internal::matrix_array<T, Size, MatrixOptions, Align>::internal::matrix_array()
+ [with T = double, int Size = 2, int MatrixOptions = 2, bool Align = true]:
+-Assertion `(reinterpret_cast<size_t>(array) & (sizemask)) == 0 && "this assertion
++Assertion (reinterpret_cast<size_t>(array) & (sizemask)) == 0 && "this assertion
+ is explained here: http://eigen.tuxfamily.org/dox-devel/group__TopicUnalignedArrayAssert.html
+ **** READ THIS WEB PAGE !!! ****"' failed.
+ </pre>
+-- 
+GitLab
+
+
+From ae263fb905b2dd9ff3ad9b47dc44f90466f7b1c8 Mon Sep 17 00:00:00 2001
+From: Guilhem Saurel <guilhem.saurel@laas.fr>
+Date: Tue, 16 Dec 2025 10:40:27 +0100
+Subject: [PATCH 4/4] doc: define eigenAutoToc alias
+
+Fix for doxygen 1.15:
+```
+doc/Manual.dox:95: error: Found unexpanded alias '\cpp17'. Check if number of arguments passed is correct.
+doc/Manual.dox:98: error: Found unexpanded alias '\eigenAutoToc'. Check if number of arguments passed is correct.
+```
+---
+ doc/Doxyfile.in | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/doc/Doxyfile.in b/doc/Doxyfile.in
+index 25a7e2e9a..445fc0a6f 100644
+--- a/doc/Doxyfile.in
++++ b/doc/Doxyfile.in
+@@ -32,7 +32,7 @@ ALIASES                = "only_for_vectors=This is only for vectors (either row-
+                          "cpp14=<span class='cpp14'>[c++14]</span>" \
+                          "cpp17=<span class='cpp17'>[c++17]</span>" \
+                          "newin{1}=<span class='newin3x'>New in %Eigen \1.</span>" \
+-                         eigenAutoToc= \
++                         "eigenAutoToc=<!-- TOC placeholder -->" \
+                          eigenManualPage=\defgroup
+ EXTENSION_MAPPING      = .h=C++ \
+                          no_extension=C++
+-- 
+GitLab
+
diff --git a/dev-cpp/eigen/files/eigen-5.0.0-please_protect_your_min_with_parentheses.patch b/dev-cpp/eigen/files/eigen-5.0.0-please_protect_your_min_with_parentheses.patch
new file mode 100644
index 000000000000..ee8ab16793cb
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-5.0.0-please_protect_your_min_with_parentheses.patch
@@ -0,0 +1,35 @@
+From 056b77036b4c97fee25bbd7a747e55c75c79cd48 Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Tue, 23 Sep 2025 00:40:14 +0200
+Subject: [PATCH] please protect your min with parentheses
+
+Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>
+
+diff --git a/Eigen/src/Core/products/Parallelizer.h b/Eigen/src/Core/products/Parallelizer.h
+index 4f36689..899d78f 100644
+--- a/Eigen/src/Core/products/Parallelizer.h
++++ b/Eigen/src/Core/products/Parallelizer.h
+@@ -141,7 +141,7 @@ inline void manage_multi_threading(Action action, int* v) {
+     // for OpenMP.
+     eigen_internal_assert(*v >= 0);
+     int omp_threads = omp_get_max_threads();
+-    m_maxThreads = (*v == 0 ? omp_threads : std::min(*v, omp_threads));
++    m_maxThreads = (*v == 0 ? omp_threads : (std::min)(*v, omp_threads));
+ #elif defined(EIGEN_GEMM_THREADPOOL)
+     // Calling action == SetAction and *v = 0 means
+     // restoring m_maxThreads to the number of threads in the ThreadPool,
+diff --git a/test/product_threaded.cpp b/test/product_threaded.cpp
+index 1782c28..85c2615 100644
+--- a/test/product_threaded.cpp
++++ b/test/product_threaded.cpp
+@@ -7,6 +7,7 @@
+ // Public License v. 2.0. If a copy of the MPL was not distributed
+ // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ 
++#define EIGEN_DONT_PARALLELIZE
+ #define EIGEN_GEMM_THREADPOOL
+ #include "main.h"
+ 
+-- 
+2.51.0
+
diff --git a/dev-cpp/eigen/files/eigen-5.0.1-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch b/dev-cpp/eigen/files/eigen-5.0.1-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch
new file mode 100644
index 000000000000..9a740351ead9
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-5.0.1-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch
@@ -0,0 +1,29 @@
+From d0e70fb11f54ccc8117030482fb7b3b359261cbf Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Mon, 22 Dec 2025 17:19:51 +0100
+Subject: Do not show deprecated CUDA device properties for CUDA-13
+
+Fixes: 9e5714b93b3a0d7848e72db5fa2b58decaa60297
+Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>
+
+diff --git a/test/gpu_common.h b/test/gpu_common.h
+index f34f1b078..f47742079 100644
+--- a/test/gpu_common.h
++++ b/test/gpu_common.h
+@@ -153,9 +153,13 @@ void ei_test_init_gpu() {
+   std::cout << "  warpSize:                    " << deviceProp.warpSize << "\n";
+   std::cout << "  regsPerBlock:                " << deviceProp.regsPerBlock << "\n";
+   std::cout << "  concurrentKernels:           " << deviceProp.concurrentKernels << "\n";
++#if defined(EIGEN_CUDA_SDK_VER) && EIGEN_CUDA_SDK_VER < 130000
+   std::cout << "  clockRate:                   " << deviceProp.clockRate << "\n";
++#endif
+   std::cout << "  canMapHostMemory:            " << deviceProp.canMapHostMemory << "\n";
++#if defined(EIGEN_CUDA_SDK_VER) && EIGEN_CUDA_SDK_VER < 130000
+   std::cout << "  computeMode:                 " << deviceProp.computeMode << "\n";
++#endif
+ }
+ 
+ #endif  // EIGEN_TEST_GPU_COMMON_H
+-- 
+2.52.0
+
diff --git a/dev-cpp/eigen/files/eigen-5.0.1-c++-20.patch b/dev-cpp/eigen/files/eigen-5.0.1-c++-20.patch
new file mode 100644
index 000000000000..c770cbe827cc
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-5.0.1-c++-20.patch
@@ -0,0 +1,29 @@
+From: Nicholas Vinson <nvinson234@gmail.com>
+Date: Mon, 15 Dec 2025 20:37:04 -0500
+
+--- a/Eigen/src/Eigenvalues/ComplexSchur.h
++++ b/Eigen/src/Eigenvalues/ComplexSchur.h
+@@ -277,7 +277,8 @@
+   using std::abs;
+   if ((iter == 10 || iter == 20) && iu > 1) {
+     // exceptional shift, taken from http://www.netlib.org/eispack/comqr.f
+-    return abs(numext::real(m_matT.coeff(iu, iu - 1))) + abs(numext::real(m_matT.coeff(iu - 1, iu - 2)));
++    return ComplexSchur<MatrixType>::ComplexScalar(
++        abs(numext::real(m_matT.coeff(iu, iu - 1))) + abs(numext::real(m_matT.coeff(iu - 1, iu - 2))));
+   }
+ 
+   // compute the shift as one of the eigenvalues of t, the 2x2
+--- a/unsupported/Eigen/src/MatrixFunctions/MatrixFunction.h
++++ b/unsupported/Eigen/src/MatrixFunctions/MatrixFunction.h
+@@ -86,7 +86,7 @@
+         for (Index i = 0; i < rows; i++)
+           mx = (std::max)(mx, std::abs(m_f(Ashifted(i, i) + avgEival, static_cast<int>(s + r))));
+         if (r != 0) rfactorial *= RealScalar(r);
+-        delta = (std::max)(delta, mx / rfactorial);
++        delta = (std::max)(delta, RealScalar(mx / rfactorial));
+       }
+       const RealScalar P_norm = P.cwiseAbs().rowwise().sum().maxCoeff();
+       if (mu * delta * P_norm < NumTraits<Scalar>::epsilon() * F_norm)  // series converged
+-- 
+2.52.0
+
diff --git a/dev-cpp/eigen/files/eigen-5.0.1-cmake-GNUInstallDirs.patch b/dev-cpp/eigen/files/eigen-5.0.1-cmake-GNUInstallDirs.patch
new file mode 100644
index 000000000000..d68e31b132ed
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-5.0.1-cmake-GNUInstallDirs.patch
@@ -0,0 +1,57 @@
+From efcf4891a83e2757aa70de61eb17d81963085c20 Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Sat, 27 Dec 2025 15:39:40 +0100
+Subject: cmake GNUInstallDirs
+
+Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>
+
+diff --git a/blas/CMakeLists.txt b/blas/CMakeLists.txt
+index 45488d7..f0f88c0 100644
+--- a/blas/CMakeLists.txt
++++ b/blas/CMakeLists.txt
+@@ -31,10 +31,8 @@ foreach(target IN LISTS EIGEN_BLAS_TARGETS)
+   endif()
+ 
+   add_dependencies(blas ${target})
+-  install(TARGETS ${target}
+-          RUNTIME DESTINATION bin
+-          LIBRARY DESTINATION lib
+-          ARCHIVE DESTINATION lib)
++  include(GNUInstallDirs)
++  install(TARGETS ${target})
+ endforeach()
+ 
+ if(EIGEN_BUILD_TESTING)
+diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
+index da07b19d6..dec130bd5 100644
+--- a/doc/CMakeLists.txt
++++ b/doc/CMakeLists.txt
+@@ -4,6 +4,8 @@ set_directory_properties(PROPERTIES EXCLUDE_FROM_ALL TRUE)
+ 
+ project(EigenDoc)
+ 
++include(GNUInstallDirs)
++
+ if(CMAKE_COMPILER_IS_GNUCXX)
+   if(CMAKE_SYSTEM_NAME MATCHES Linux)
+     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O1 -g1")
+diff --git a/lapack/CMakeLists.txt b/lapack/CMakeLists.txt
+index d837fff..9e127a6 100644
+--- a/lapack/CMakeLists.txt
++++ b/lapack/CMakeLists.txt
+@@ -120,10 +120,8 @@ foreach(target IN LISTS EIGEN_LAPACK_TARGETS)
+   endif()
+   target_link_libraries(${target} Eigen3::Eigen)
+   add_dependencies(lapack ${target})
+-  install(TARGETS ${target}
+-          RUNTIME DESTINATION bin
+-          LIBRARY DESTINATION lib
+-          ARCHIVE DESTINATION lib)
++  include(GNUInstallDirs)
++  install(TARGETS ${target})
+ endforeach()
+ 
+ 
+-- 
+2.52.0
+
diff --git a/dev-cpp/eigen/files/eigen-5.0.1-fix-lapack_testing.py.patch b/dev-cpp/eigen/files/eigen-5.0.1-fix-lapack_testing.py.patch
new file mode 100644
index 000000000000..cbba85d882cb
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-5.0.1-fix-lapack_testing.py.patch
@@ -0,0 +1,248 @@
+From 8d05fb579428b57a784f72e054295ebfeac5864d Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Fri, 13 Mar 2026 18:43:46 +0100
+Subject: fix lapack_testing.py
+
+Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>
+
+diff --git a/lapack/testing/lapack_testing.py b/lapack/testing/lapack_testing.py
+index 3bd9462..b35e15d 100755
+--- a/lapack/testing/lapack_testing.py
++++ b/lapack/testing/lapack_testing.py
+@@ -15,9 +15,9 @@ try:
+    opts, args = getopt.getopt(sys.argv[1:], "hd:srep:t:n", 
+                               ["help", "dir", "short", "run", "error","prec=","test=","number"])
+    
+-except getopt.error, msg:
+-   print msg
+-   print "for help use --help"
++except (getopt.error, msg):
++   print(msg)
++   print("for help use --help")
+    sys.exit(2)
+ 
+ short_summary=0
+@@ -29,38 +29,38 @@ only_numbers=0
+ dir="TESTING"
+ for o, a in opts:
+    if o in ("-h", "--help"):
+-      print sys.argv[0]+" [-h|--help] [-d dir |--dir dir] [-s |--short] [-r |--run] [-e |--error] [-p p |--prec p] [-t test |--test test] [-n | --number]"
+-      print "     - h is to print this message"
+-      print "     - r is to use to run the LAPACK tests then analyse the output (.out files). By default, the script will not run all the LAPACK tests"
+-      print "     - d [dir] is to indicate where is the LAPACK testing directory (.out files). By default, the script will use ."
+-      print " LEVEL OF OUTPUT"
+-      print "     - x is to print a detailed summary"
+-      print "     - e is to print only the error summary"
+-      print "     - s is to print a short summary"
+-      print "     - n is to print the numbers of failing tests (turn on summary mode)"
+-      print " SECLECTION OF TESTS:"
+-      print "     - p [s/c/d/z/x] is to indicate the PRECISION to run:"
+-      print "            s=single"
+-      print "            d=double"
+-      print "            sd=single/double"
+-      print "            c=complex"
+-      print "            z=double complex"
+-      print "            cz=complex/double complex"
+-      print "            x=all [DEFAULT]"
+-      print "     - t [lin/eig/mixed/rfp/all] is to indicate which TEST FAMILY to run:"
+-      print "            lin=Linear Equation"
+-      print "            eig=Eigen Problems"
+-      print "            mixed=mixed-precision"
+-      print "            rfp=rfp format"
+-      print "            all=all tests [DEFAULT]"
+-      print " EXAMPLES:"
+-      print "     ./lapack_testing.py -n"
+-      print "            Will return the numbers of failed tests by analyzing the LAPACK output"
+-      print "     ./lapack_testing.py -n -r -p s"
+-      print "            Will return the numbers of failed tests in REAL precision by running the LAPACK Tests then analyzing the output"
+-      print "     ./lapack_testing.py -n -p s -t eig "
+-      print "            Will return the numbers of failed tests in REAL precision by analyzing only the LAPACK output of EIGEN testings"
+-      print "Written by Julie Langou (June 2011) "
++      print(sys.argv[0]+" [-h|--help] [-d dir |--dir dir] [-s |--short] [-r |--run] [-e |--error] [-p p |--prec p] [-t test |--test test] [-n | --number]")
++      print("     - h is to print this message")
++      print("     - r is to use to run the LAPACK tests then analyse the output (.out files). By default, the script will not run all the LAPACK tests")
++      print("     - d [dir] is to indicate where is the LAPACK testing directory (.out files). By default, the script will use .")
++      print(" LEVEL OF OUTPUT")
++      print("     - x is to print a detailed summary")
++      print("     - e is to print only the error summary")
++      print("     - s is to print a short summary")
++      print("     - n is to print the numbers of failing tests (turn on summary mode)")
++      print(" SECLECTION OF TESTS:")
++      print("     - p [s/c/d/z/x] is to indicate the PRECISION to run:")
++      print("            s=single")
++      print("            d=double")
++      print("            sd=single/double")
++      print("            c=complex")
++      print("            z=double complex")
++      print("            cz=complex/double complex")
++      print("            x=all [DEFAULT]")
++      print("     - t [lin/eig/mixed/rfp/all] is to indicate which TEST FAMILY to run:")
++      print("            lin=Linear Equation")
++      print("            eig=Eigen Problems")
++      print("            mixed=mixed-precision")
++      print("            rfp=rfp format")
++      print("            all=all tests [DEFAULT]")
++      print(" EXAMPLES:")
++      print("     ./lapack_testing.py -n")
++      print("            Will return the numbers of failed tests by analyzing the LAPACK output")
++      print("     ./lapack_testing.py -n -r -p s")
++      print("            Will return the numbers of failed tests in REAL precision by running the LAPACK Tests then analyzing the output")
++      print("     ./lapack_testing.py -n -p s -t eig ")
++      print("            Will return the numbers of failed tests in REAL precision by analyzing only the LAPACK output of EIGEN testings")
++      print("Written by Julie Langou (June 2011) ")
+       sys.exit(0)
+    else:
+       if o in ("-s", "--short"):
+@@ -120,34 +120,34 @@ def run_summary_test( f, cmdline, short_summary):
+       error_message=cmdline+" did not work"
+ 
+    if r != 0 and not with_file:
+-       print "---- TESTING " + cmdline.split()[0] + "... FAILED(" + error_message +") !"
++       print("---- TESTING " + cmdline.split()[0] + "... FAILED(" + error_message +") !")
+        for line in pipe.readlines():
+           f.write(str(line))
+    elif r != 0 and with_file and not short_summary:
+-       print "---- WARNING: please check that you have the LAPACK output : "+cmdline+"!"
+-       print "---- WARNING: with the option -r, we can run the LAPACK testing for you"
++       print("---- WARNING: please check that you have the LAPACK output : "+cmdline+"!")
++       print("---- WARNING: with the option -r, we can run the LAPACK testing for you")
+       # print "---- "+error_message
+    else:
+          for line in pipe.readlines():
+-        	f.write(str(line))
+-        	words_in_line=line.split()
+-        	if (line.find("run")!=-1):
+-#        	   print line
+-        	   whereisrun=words_in_line.index("run)")
+-        	   nb_test_run+=int(words_in_line[whereisrun-2])
+-        	if (line.find("out of")!=-1):
+-        	   if (short_summary==0): print line,
+-        	   whereisout= words_in_line.index("out")
+-        	   nb_test_fail+=int(words_in_line[whereisout-1])
+-        	if (line.find("illegal")!=-1):
+-        	   if (short_summary==0):print line,
+-        	   nb_test_illegal+=1
+-        	if (line.find(" INFO")!=-1):
+-        	   if (short_summary==0):print line,
+-        	   nb_test_info+=1
+-        	if (with_file==1):
+-        	   pipe.close()
+-           
++                f.write(str(line))
++                words_in_line=line.split()
++                if (line.find("run")!=-1):
++#                   print line
++                   whereisrun=words_in_line.index("run)")
++                   nb_test_run+=int(words_in_line[whereisrun-2])
++                if (line.find("out of")!=-1):
++                   if (short_summary==0): print(line),
++                   whereisout= words_in_line.index("out")
++                   nb_test_fail+=int(words_in_line[whereisout-1])
++                if (line.find("illegal")!=-1):
++                   if (short_summary==0):print(line),
++                   nb_test_illegal+=1
++                if (line.find(" INFO")!=-1):
++                   if (short_summary==0):print(line),
++                   nb_test_info+=1
++                if (with_file==1):
++                   pipe.close()
++
+    f.flush();
+ 
+    return [nb_test_run,nb_test_fail,nb_test_illegal,nb_test_info]
+@@ -161,10 +161,10 @@ except IOError:
+      f = sys.stdout
+ 
+ if (short_summary==0):
+-   print " "
+-   print "---------------- Testing LAPACK Routines ----------------"
+-   print " "
+-   print "-- Detailed results are stored in", filename
++   print(" ")
++   print("---------------- Testing LAPACK Routines ----------------")
++   print(" ")
++   print("-- Detailed results are stored in", filename)
+ 
+ dtypes = (
+ ("s", "d", "c", "z"),
+@@ -211,9 +211,9 @@ for dtype in range_prec:
+   name = dtypes[1][dtype]
+ 
+   if (short_summary==0):
+-     print " "
+-     print "------------------------- %s ------------------------" % name
+-     print " "
++     print(" ")
++     print("------------------------- %s ------------------------" % name)
++     print(" ")
+      sys.stdout.flush()
+ 
+ 
+@@ -260,8 +260,8 @@ for dtype in range_prec:
+            # EIG TESTS
+            cmdbase="xeigtst"+letter+" < "+dtests[0][dtest]+".in > "+dtests[2][dtest]+".out"
+      if (not just_errors and not short_summary):
+-        print "-->  Testing "+name+" "+dtests[1][dtest]+" [ "+cmdbase+" ]"
+-     # Run the process: either to read the file or run the LAPACK testing   
++        print("-->  Testing "+name+" "+dtests[1][dtest]+" [ "+cmdbase+" ]")
++     # Run the process: either to read the file or run the LAPACK testing
+      nb_test = run_summary_test(f, cmdbase, short_summary)
+      list_results[0][dtype]+=nb_test[0]
+      list_results[1][dtype]+=nb_test[1]
+@@ -271,21 +271,21 @@ for dtype in range_prec:
+      
+      if (not short_summary):
+         if (nb_test[0]>0 and just_errors==0):
+-           print "-->  Tests passed: "+str(nb_test[0])
++           print("-->  Tests passed: "+str(nb_test[0]))
+         if (nb_test[1]>0):
+-           print "-->  Tests failing to pass the threshold: "+str(nb_test[1])
++           print("-->  Tests failing to pass the threshold: "+str(nb_test[1]))
+         if (nb_test[2]>0):
+-           print "-->  Illegal Error: "+str(nb_test[2])
++           print("-->  Illegal Error: "+str(nb_test[2]))
+         if (nb_test[3]>0):
+-           print "-->  Info Error: "+str(nb_test[3])
++           print("-->  Info Error: "+str(nb_test[3]))
+         if (got_error>0 and just_errors==1):
+-           print "ERROR IS LOCATED IN "+name+" "+dtests[1][dtest]+" [ "+cmdbase+" ]"
+-           print ""
++           print("ERROR IS LOCATED IN "+name+" "+dtests[1][dtest]+" [ "+cmdbase+" ]")
++           print("")
+         if (just_errors==0):
+-           print ""
++           print("")
+ #     elif (got_error>0):
+-#        print dtests[2][dtest]+".out \t"+str(nb_test[1])+"\t"+str(nb_test[2])+"\t"+str(nb_test[3])
+         
++#        print(dtests[2][dtest]+".out \t"+str(nb_test[1])+"\t"+str(nb_test[2])+"\t"+str(nb_test[3]))
+      sys.stdout.flush()
+   if (list_results[0][dtype] > 0 ):
+      percent_num_error=float(list_results[1][dtype])/float(list_results[0][dtype])*100
+@@ -300,9 +300,9 @@ for dtype in range_prec:
+   list_results[3][4]+=list_results[3][dtype]
+   
+ if only_numbers==1:
+-   print str(list_results[1][4])+"\n"+str(list_results[2][4]+list_results[3][4])
++   print(str(list_results[1][4])+"\n"+str(list_results[2][4]+list_results[3][4]))
+ else:
+-   print summary
++   print(summary)
+    if (list_results[0][4] > 0 ):
+       percent_num_error=float(list_results[1][4])/float(list_results[0][4])*100
+       percent_error=float(list_results[2][4]+list_results[3][4])/float(list_results[0][4])*100
+@@ -310,9 +310,9 @@ else:
+       percent_num_error=0
+       percent_error=0
+    if (prec=='x'):
+-        print "--> ALL PRECISIONS\t"+str(list_results[0][4])+"\t\t"+str(list_results[1][4])+"\t("+"%.3f" % percent_num_error+"%)\t"+str(list_results[2][4]+list_results[3][4])+"\t("+"%.3f" % percent_error+"%)\t""\n"
++        print("--> ALL PRECISIONS\t"+str(list_results[0][4])+"\t\t"+str(list_results[1][4])+"\t("+"%.3f" % percent_num_error+"%)\t"+str(list_results[2][4]+list_results[3][4])+"\t("+"%.3f" % percent_error+"%)\t""\n")
+    if list_results[0][4] == 0:
+-     print "NO TESTS WERE ANALYZED, please use the -r option to run the LAPACK TESTING"
++     print("NO TESTS WERE ANALYZED, please use the -r option to run the LAPACK TESTING")
+ 
+ # This may close the sys.stdout stream, so make it the last statement
+ f.close()
+-- 
+2.53.0
+
diff --git a/dev-cpp/eigen/files/eigen-5.0.1-make-static-libs-optional.patch b/dev-cpp/eigen/files/eigen-5.0.1-make-static-libs-optional.patch
new file mode 100644
index 000000000000..63272d4a82d8
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-5.0.1-make-static-libs-optional.patch
@@ -0,0 +1,61 @@
+From 9ddec05248d0084c4bfe737fa9ab3cf61f3ecd4a Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Thu, 12 Mar 2026 16:38:02 +0100
+Subject: make static libs optional
+
+Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>
+
+diff --git a/blas/CMakeLists.txt b/blas/CMakeLists.txt
+index 2bd498a11..0b605cc9e 100644
+--- a/blas/CMakeLists.txt
++++ b/blas/CMakeLists.txt
+@@ -15,8 +15,10 @@ set(EigenBlas_SRCS  single.cpp double.cpp complex_single.cpp complex_double.cpp
+ 
+ set(EIGEN_BLAS_TARGETS "")
+ 
++if (EIGEN_BUILD_STATIC_LIBS)
+ add_library(eigen_blas_static STATIC ${EigenBlas_SRCS})
+ list(APPEND EIGEN_BLAS_TARGETS eigen_blas_static)
++endif()
+ 
+ if (EIGEN_BUILD_SHARED_LIBS)
+   add_library(eigen_blas SHARED ${EigenBlas_SRCS} "eigen_blas.def")
+@@ -34,7 +36,9 @@ foreach(target IN LISTS EIGEN_BLAS_TARGETS)
+ 
+   add_dependencies(blas ${target})
+   include(GNUInstallDirs)
++  if (NOT EIGEN_INSTALL_STATIC_LIBS AND NOT ${target} EQUAL eigen_blas_static)
+   install(TARGETS ${target})
++  endif()
+ endforeach()
+ 
+ if(EIGEN_BUILD_TESTING)
+diff --git a/lapack/CMakeLists.txt b/lapack/CMakeLists.txt
+index f98f77afc..4ea553b56 100644
+--- a/lapack/CMakeLists.txt
++++ b/lapack/CMakeLists.txt
+@@ -101,9 +101,11 @@ endif()
+ 
+ set(EIGEN_LAPACK_TARGETS "")
+ 
++if (EIGEN_BUILD_STATIC_LIBS)
+ add_library(eigen_lapack_static STATIC ${EigenLapack_SRCS} ${ReferenceLapack_SRCS})
+ target_link_libraries(eigen_lapack_static  eigen_blas_static)
+ list(APPEND EIGEN_LAPACK_TARGETS eigen_lapack_static)
++endif()
+ 
+ if (EIGEN_BUILD_SHARED_LIBS)
+   add_library(eigen_lapack SHARED ${EigenLapack_SRCS} ${EIGEN_LAPACK_DEF})
+@@ -123,7 +125,9 @@ foreach(target IN LISTS EIGEN_LAPACK_TARGETS)
+   target_link_libraries(${target} Eigen3::Eigen)
+   add_dependencies(lapack ${target})
+   include(GNUInstallDirs)
++  if (NOT EIGEN_INSTALL_STATIC_LIBS AND NOT ${target} EQUAL eigen_lapack_static)
+   install(TARGETS ${target})
++  endif()
+ endforeach()
+ 
+ 
+-- 
+2.53.0
+
diff --git a/dev-cpp/eigen/files/eigen-9999-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch b/dev-cpp/eigen/files/eigen-9999-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch
new file mode 100644
index 000000000000..0d762191009c
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-9999-Do-not-show-deprecated-CUDA-device-properties-for-CU.patch
@@ -0,0 +1,29 @@
+From f14dfe5022870966d0d888651f0d4f5b3af5f25c Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Mon, 22 Dec 2025 17:19:51 +0100
+Subject: Do not show deprecated CUDA device properties for CUDA-13
+
+Fixes: 9e5714b93b3a0d7848e72db5fa2b58decaa60297
+Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>
+
+diff --git a/test/gpu_common.h b/test/gpu_common.h
+index 8c7049b17..f47742079 100644
+--- a/test/gpu_common.h
++++ b/test/gpu_common.h
+@@ -153,7 +153,13 @@ void ei_test_init_gpu() {
+   std::cout << "  warpSize:                    " << deviceProp.warpSize << "\n";
+   std::cout << "  regsPerBlock:                " << deviceProp.regsPerBlock << "\n";
+   std::cout << "  concurrentKernels:           " << deviceProp.concurrentKernels << "\n";
++#if defined(EIGEN_CUDA_SDK_VER) && EIGEN_CUDA_SDK_VER < 130000
++  std::cout << "  clockRate:                   " << deviceProp.clockRate << "\n";
++#endif
+   std::cout << "  canMapHostMemory:            " << deviceProp.canMapHostMemory << "\n";
++#if defined(EIGEN_CUDA_SDK_VER) && EIGEN_CUDA_SDK_VER < 130000
++  std::cout << "  computeMode:                 " << deviceProp.computeMode << "\n";
++#endif
+ }
+ 
+ #endif  // EIGEN_TEST_GPU_COMMON_H
+-- 
+2.53.0
+
diff --git a/dev-cpp/eigen/files/eigen-9999-product_threaded_dont_parallelize.patch b/dev-cpp/eigen/files/eigen-9999-product_threaded_dont_parallelize.patch
new file mode 100644
index 000000000000..4153896b3933
--- /dev/null
+++ b/dev-cpp/eigen/files/eigen-9999-product_threaded_dont_parallelize.patch
@@ -0,0 +1,22 @@
+From 056b77036b4c97fee25bbd7a747e55c75c79cd48 Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Tue, 23 Sep 2025 00:40:14 +0200
+Subject: [PATCH] product_threaded don't parallelize
+
+Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>
+
+diff --git a/test/product_threaded.cpp b/test/product_threaded.cpp
+index 1782c28..85c2615 100644
+--- a/test/product_threaded.cpp
++++ b/test/product_threaded.cpp
+@@ -8,6 +8,7 @@
+ // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ // SPDX-License-Identifier: MPL-2.0
+ 
++#define EIGEN_DONT_PARALLELIZE
+ #define EIGEN_GEMM_THREADPOOL
+ #include "main.h"
+ 
+-- 
+2.51.0
+
diff --git a/dev-cpp/eigen/metadata.xml b/dev-cpp/eigen/metadata.xml
new file mode 100644
index 000000000000..c15af35ef933
--- /dev/null
+++ b/dev-cpp/eigen/metadata.xml
@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "https://docs.baldeagleos.com/dtd/metadata.dtd">
+<pkgmetadata>
+  <maintainer type="project">
+    <email>sci@gentoo.org</email>
+    <name>Gentoo Science Project</name>
+  </maintainer>
+  <maintainer type="project">
+    <email>kde@gentoo.org</email>
+    <name>Gentoo KDE Project</name>
+  </maintainer>
+  <longdescription>
+		Eigen is a lightweight C++ template library for vector and matrix math,
+		a.k.a. linear algebra. Unlike most other linear algebra libraries, Eigen
+		focuses on the simple mathematical needs of applications: games and other
+		OpenGL apps, spreadsheets and other office apps, etc. Eigen is dedicated to
+		providing optimal speed with GCC.
+	</longdescription>
+  <use>
+    <flag name="adolc">Add test support for Adolc (<pkg>sci-libs/adolc</pkg>)</flag>
+    <flag name="blas">Build the Eigen Blas library</flag>
+    <flag name="boost">Add test support for Boost.Multiprecision (<pkg>dev-libs/boost</pkg>)</flag>
+    <flag name="cholmod">Add test support for CHOLMOD (<pkg>sci-libs/cholmod</pkg>)</flag>
+    <flag name="clang">Use clang for cuda units compilation</flag>
+    <flag name="cuda-clang">Use clang for cuda units compilation</flag>
+    <flag name="fftw">Add test support for fftw (<pkg>sci-libs/fftw</pkg>)</flag>
+    <flag name="hip">Enable HIP GPU computing support</flag>
+    <flag name="klu">Add test support for KLU (<pkg>sci-libs/klu</pkg>)</flag>
+    <flag name="lapack">Build the included Eigen LAPACK library</flag>
+    <flag name="mathjax">Use MathJax for rendering math in HTML docs (dev-libs/mathjax)</flag>
+    <flag name="metis">Add test support for METIS (<pkg>sci-libs/metis</pkg>)</flag>
+    <flag name="opengl">Add test support for OpenGL</flag>
+    <flag name="openmp">Add test support for OpenMP (support parallel computing)</flag>
+    <flag name="pastix">Add test support for PaStiX (<pkg>sci-libs/pastix</pkg>)</flag>
+    <flag name="pocketfft">Add test support for pocketfft (<pkg>dev-libs/pocketfft</pkg>)</flag>
+    <flag name="sparsehash">Add test support for GoogleHash (<pkg>dev-cpp/sparsehash</pkg>)</flag>
+    <flag name="spqr">Add test support for SPQR (<pkg>sci-libs/spqr</pkg>)</flag>
+    <flag name="superlu">Add test support for SuperLU (<pkg>sci-libs/superlu</pkg>)</flag>
+    <flag name="umfpack">Add test support for UMFPACK (<pkg>sci-libs/umfpack</pkg>)</flag>
+  </use>
+  <origin>baldeagleos-repo</origin>
+</pkgmetadata>