eigen

USE flags

• cpu_flags_arm_neon - Use the NEON (ASIMD) instruction set
• cpu_flags_ppc_altivec - Use the AltiVec/VMX instruction set
• cpu_flags_ppc_vsx - Use the Vector Scalar Extension instruction set (POWER7 and later)
• cuda - Build with cuda support
• debug - Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
• doc - Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
• openmp - Build support for the OpenMP (support parallel computing), requires >=sys-devel/gcc-4.2 built with USE="openmp"
• test - Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)