1 static char help[] = "Tests sequential and parallel MatGetRow() and MatRestoreRow().\n";
2
3 #include <petscmat.h>
4
main(int argc,char ** args)5 int main(int argc, char **args)
6 {
7 Mat C;
8 PetscInt i, j, m = 5, n = 5, Ii, J, nz, rstart, rend;
9 PetscMPIInt rank;
10 const PetscInt *idx;
11 PetscScalar v;
12 const PetscScalar *values;
13
14 PetscFunctionBeginUser;
15 PetscCall(PetscInitialize(&argc, &args, NULL, help));
16 /* Create the matrix for the five point stencil, YET AGAIN */
17 PetscCall(MatCreate(PETSC_COMM_WORLD, &C));
18 PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
19 PetscCall(MatSetFromOptions(C));
20 PetscCall(MatSetUp(C));
21 for (i = 0; i < m; i++) {
22 for (j = 0; j < n; j++) {
23 v = -1.0;
24 Ii = j + n * i;
25 if (i > 0) {
26 J = Ii - n;
27 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
28 }
29 if (i < m - 1) {
30 J = Ii + n;
31 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
32 }
33 if (j > 0) {
34 J = Ii - 1;
35 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
36 }
37 if (j < n - 1) {
38 J = Ii + 1;
39 PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
40 }
41 v = 4.0;
42 PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
43 }
44 }
45 PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
46 PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
47 PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
48
49 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
50 PetscCall(MatGetOwnershipRange(C, &rstart, &rend));
51 for (i = rstart; i < rend; i++) {
52 PetscCall(MatGetRow(C, i, &nz, &idx, &values));
53 if (rank == 0) {
54 for (j = 0; j < nz; j++) PetscCall(PetscPrintf(PETSC_COMM_SELF, "%" PetscInt_FMT " %g ", idx[j], (double)PetscRealPart(values[j])));
55 PetscCall(PetscPrintf(PETSC_COMM_SELF, "\n"));
56 }
57 PetscCall(MatRestoreRow(C, i, &nz, &idx, &values));
58 }
59
60 PetscCall(MatDestroy(&C));
61 PetscCall(PetscFinalize());
62 return 0;
63 }
64
65 /*TEST
66
67 test:
68
69 TEST*/
70