Hi all, I wish to extract a parallel AIJ submatrix (B) from another parallel AIJ matrix (A), in particular, if I have an NxN matrix, I wish to extract the first N-1 rows and N-1 columns of A.
I can do this perfectly fine when running my code sequentially using ISCreateStride and MatGetSubMatrix like so: ISCreateStride(PETSC_COMM_WORLD,N,1,1,&is); MatGetSubMatrix(A,is,is,MAT_INITIAL_MATRIX,&B); And it behaves as I would expect, but when running in parallel, the B matrix increases past it's allocated size of N-1xN-1. I've pasted the example of a simple example output below: ORIGINAL SEQUENTIAL MATRIX row 0: (0, 1) (1, 2) (2, 3) (3, 4) row 1: (0, 1) (1, 2) (2, 3) (3, 4) row 2: (0, 1) (1, 2) (2, 3) (3, 4) row 3: (0, 1) (1, 2) (2, 3) (3, 4) SEQUENTIAL SUBMATRIX row 0: (0, 1) (1, 2) (2, 3) row 1: (0, 1) (1, 2) (2, 3) row 2: (0, 1) (1, 2) (2, 3) ORIGINAL PARALLEL MATRIX row 0: (0, 1) (1, 2) (2, 3) (3, 4) row 1: (0, 1) (1, 2) (2, 3) (3, 4) row 2: (0, 1) (1, 2) (2, 3) (3, 4) row 3: (0, 1) (1, 2) (2, 3) (3, 4) PARALLEL "SUBMATRIX" row 0: (3, 1) (4, 2) (5, 3) row 1: (3, 1) (4, 2) (5, 3) row 2: (3, 1) (4, 2) (5, 3) row 3: (3, 1) (4, 2) (5, 3) row 4: (3, 1) (4, 2) (5, 3) row 5: (3, 1) (4, 2) (5, 3) I'm not really sure what is going on with the index set, and I would really appreciate some help. Thanks, Arthur
