petsc3.15.0 20210405
MATIS
MATIS = "is"  A matrix type to be used for using the nonoverlapping domain decomposition methods (e.g. PCBDDC or KSPFETIDP). This stores the matrices in globally unassembled form. Each processor assembles only its local Neumann problem and the parallel matrix vector product is handled "implicitly".
Options Database Keys
 mat_type is   sets the matrix type to "is" during a call to MatSetFromOptions()

 matis_fixempty   Fixes local matrices in case of empty local rows/columns.

 matis_storel2l   stores the localtolocal operators generated by the Galerkin process of MatPtAP().

Notes
Options prefix for the inner matrix are given by is_mat_xxx
You must call MatSetLocalToGlobalMapping() before using this matrix type.
You can do matrix preallocation on the local matrix after you obtain it with
MatISGetLocalMat(); otherwise, you could use MatISSetPreallocation()
See Also
Mat, MatISGetLocalMat(), MatSetLocalToGlobalMapping(), MatISSetPreallocation(), MatCreateIS(), PCBDDC, KSPFETIDP
Level
advanced
Location
src/mat/impls/is/matis.c
Examples
src/ksp/ksp/tutorials/ex29.c.html
src/ksp/ksp/tutorials/ex34.c.html
src/ksp/ksp/tutorials/ex71.c.html
src/ksp/ksp/tutorials/ex72.c.html
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages