#include "petscmat.h" int MatGetSubMatrix(Mat mat,IS isrow,IS iscol,int csize,MatReuse cll,Mat *newmat)Collective on Mat
| mat | - the original matrix | |
| isrow | - rows this processor should obtain | |
| iscol | - columns for all processors you wish to keep | |
| csize | - number of columns "local" to this processor (does nothing for sequential matrices). This should match the result from VecGetLocalSize(x,...) if you plan to use the matrix in a A*x; alternatively, you can use PETSC_DECIDE | |
| cll | - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX |
Notes: the iscol argument MUST be the same on each processor. You might be able to create the iscol argument with ISAllGather().
The first time this is called you should use a cll of MAT_INITIAL_MATRIX, the MatGetSubMatrix() routine will create the newmat for you. Any additional calls to this routine with a mat of the same nonzero structure will reuse the matrix generated the first time.
Level:advanced
Location:src/mat/interface/matrix.c
Index of all Mat routines
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