#include "petscmat.h" PetscErrorCode MatGetLocalSubMatrix(Mat mat,IS isrow,IS iscol,Mat *submat)Not Collective
Depending on the format of mat, the returned submat may not implement MatMult(). Its communicator may be the same as mat, it may be PETSC_COMM_SELF, or some other subcomm of mat's.
The submat always implements MatSetValuesLocal(). If isrow and iscol have the same block size, then MatSetValuesBlockedLocal() will also be implemented.
The mat must have had a ISLocalToGlobalMapping provided to it with MatSetLocalToGlobalMapping(). Note that matrices obtained with DMCreateMat() generally already have the local to global mapping provided.
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages