Readme_ordering.md

MUMPS ordering

MUMPS by default uses PORD for ordering. MUMPS can optionally use ordering libraries Scotch, METIS, and/or ParMETIS, which will be automatically built if needed.

Scotch

Build Scotch without trying to find it:

cmake -DMUMPS_scotch=yes

Optionally, to try to find a system Scotch library, falling back to build Scotch if it's not found. Optionally, specify the location of Scotch with CMake option `-DSCOTCH_ROOT=/path/to/scotch"

cmake -DMUMPS_scotch=yes -DMUMPS_find_scotch=yes

By default, if "MUMPS_parallel=yes", then PTScotch will be used for parallel ordering by auto-setting "MUMPS_ptscotch=yes". This can be overriden to use non-parallel scotch like:

cmake -DMUMPS_scotch=yes -DMUMPS_ptscotch=no

METIS / ParMETIS

cmake -DMUMPS_metis=yes

cmake -DMUMPS_parmetis=yes

optionally, try to find METIS or ParMETIS before building if needed:

cmake -DMUMPS_metis=yes -DMUMPS_find_metis=yes

# or

cmake -DMUMPS_parmetis=yes -DMUMPS_find_metis=yes

Build MUMPS

cmake --build build
cmake --install build

Example

Test that MUMPS can be used with an example application. The MUMPS installed package will know what if any external ordering libraries are needed and where to find them.

Build MUMPS example:

cmake -S example -B example/build -DMUMPS_ROOT=build/local

cmake --build example/build

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If 64-bit integers are needed, use:

cmake -DMUMPS_intsize64=true