Actual source code: ex21.c
2: static char help[] = "Tests converting a parallel AIJ formatted matrix to the parallel Row format.\n\
3: This also tests MatGetRow() and MatRestoreRow() for the parallel case.\n\n";
5: #include <petscmat.h>
7: int main(int argc, char **args)
8: {
9: Mat C, A;
10: PetscInt i, j, m = 3, n = 2, Ii, J, rstart, rend, nz;
11: PetscMPIInt rank, size;
12: const PetscInt *idx;
13: PetscScalar v;
14: const PetscScalar *values;
16: PetscFunctionBeginUser;
17: PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
18: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
19: PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
20: n = 2 * size;
22: /* create the matrix for the five point stencil, YET AGAIN*/
23: PetscCall(MatCreate(PETSC_COMM_WORLD, &C));
24: PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
25: PetscCall(MatSetFromOptions(C));
26: PetscCall(MatMPIAIJSetPreallocation(C, 5, NULL, 5, NULL));
27: PetscCall(MatSeqAIJSetPreallocation(C, 5, NULL));
28: for (i = 0; i < m; i++) {
29: for (j = 2 * rank; j < 2 * rank + 2; j++) {
30: v = -1.0;
31: Ii = j + n * i;
32: if (i > 0) {
33: J = Ii - n;
34: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
35: }
36: if (i < m - 1) {
37: J = Ii + n;
38: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
39: }
40: if (j > 0) {
41: J = Ii - 1;
42: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
43: }
44: if (j < n - 1) {
45: J = Ii + 1;
46: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
47: }
48: v = 4.0;
49: PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
50: }
51: }
52: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
53: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
54: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_INFO));
55: PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
56: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
57: PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
59: PetscCall(MatGetOwnershipRange(C, &rstart, &rend));
60: for (i = rstart; i < rend; i++) {
61: PetscCall(MatGetRow(C, i, &nz, &idx, &values));
62: PetscCall(PetscSynchronizedFPrintf(PETSC_COMM_WORLD, stdout, "[%d] get row %" PetscInt_FMT ": ", rank, i));
63: for (j = 0; j < nz; j++) PetscCall(PetscSynchronizedFPrintf(PETSC_COMM_WORLD, stdout, "%" PetscInt_FMT " %g ", idx[j], (double)PetscRealPart(values[j])));
64: PetscCall(PetscSynchronizedFPrintf(PETSC_COMM_WORLD, stdout, "\n"));
65: PetscCall(MatRestoreRow(C, i, &nz, &idx, &values));
66: }
67: PetscCall(PetscSynchronizedFlush(PETSC_COMM_WORLD, stdout));
69: PetscCall(MatConvert(C, MATSAME, MAT_INITIAL_MATRIX, &A));
70: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_INFO));
71: PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
72: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
73: PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
75: PetscCall(MatDestroy(&A));
76: PetscCall(MatDestroy(&C));
77: PetscCall(PetscFinalize());
78: return 0;
79: }
81: /*TEST
83: test:
84: args: -mat_type seqaij
86: TEST*/