Readme_LAPACK.md

LAPACK options

The underlying "LAPACK" linear algebra interface is available from several vendors. By default, the generic LAPACK library "lapack" is searched for.

To specify a particular LAPACK library, use CMake configure variable "LAPACK_VENDOR" using one of the following vendors:

• AOCL AMD Optimizing CPU Libraries
• Atlas Automatically Tuned Linear Algebra Software
• MKL Intel oneMKL: requires oneMKL >= 2021.3
• Netlib Netlib LAPACK (default)
• OpenBLAS OpenBLAS

For example, to use OpenBLAS:

cmake -DLAPACK_VENDOR=OpenBLAS

Optionally, hint the location the LAPACK library like:

cmake -DLAPACK_ROOT=/path/to/lapack

Intel MKL

CMake searchs for Intel oneMKL if environment variables MKLROOT is set:

• Base Toolkit: MKL LAPACK
• HPC toolkit: SCALAPACK.

GEMMT symmetric matrix-matrix multiplication

For MUMPS ≥ 5.2.0, GEMMT symmetric matrix-matrix multiplication is recommended by the MUMPS User Guide if available. By default GEMMT is ON, but may be disabled like:

cmake -Dgemmt=off

Build LAPACK

If the compiler doesn't have LAPACK and SCALAPACK, first build and install them:

cmake -S scripts -B scripts/build -DCMAKE_INSTALL_PREFIX=~/mylibs
cmake --build scripts/build -t scalapack

# mumps
cmake -B build -DCMAKE_PREFIX_PATH=~/mylibs
cmake --build build

Since oneAPI comes with LAPACK and ScaLAPACK with oneAPI in oneMKL, there is no need to build them with oneAPI + oneMKL.