mpich

USE flags

• abi_mips_n32 - 64-bit (32-bit pointer) libraries
• abi_mips_n64 - 64-bit libraries
• abi_mips_o32 - 32-bit libraries
• abi_s390_32 - 32-bit (s390) libraries
• abi_s390_64 - 64-bit (s390x) libraries
• abi_x86_32 - 32-bit (x86) libraries
• abi_x86_64 - 64-bit (amd64) libraries
• abi_x86_x32 - x32 ABI libraries
• cxx - Build support for C++ (bindings, extra libraries, code generation, ...)
• doc - Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
• fortran - Add support for fortran
• mpi-threads - Enable MPI_THREAD_MULTIPLE
• romio - Build the ROMIO MPI-IO component
• threads - Add threads support for various packages. Usually pthreads
• valgrind - Enable annotations for accuracy. May slow down runtime slightly. Safe to use even if not currently using dev-util/valgrind