1 static char help[] = "Saves a rectangular sparse matrix to disk.\n\n";
2
3 #include <petscmat.h>
4
main(int argc,char ** args)5 int main(int argc, char **args)
6 {
7 Mat A;
8 PetscInt m = 100, n = 11, js[11], i, j, cnt;
9 PetscScalar values[11];
10 PetscViewer view;
11
12 PetscFunctionBeginUser;
13 PetscCall(PetscInitialize(&argc, &args, NULL, help));
14 PetscCall(MatCreateSeqAIJ(PETSC_COMM_WORLD, m, n, 20, 0, &A));
15
16 for (i = 0; i < n; i++) values[i] = (PetscReal)i;
17
18 for (i = 0; i < m; i++) {
19 cnt = 0;
20 if (i % 2) {
21 for (j = 0; j < n; j += 2) js[cnt++] = j;
22 }
23 PetscCall(MatSetValues(A, 1, &i, cnt, js, values, INSERT_VALUES));
24 }
25 PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
26 PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
27
28 PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, "rect", FILE_MODE_WRITE, &view));
29 PetscCall(MatView(A, view));
30 PetscCall(PetscViewerDestroy(&view));
31
32 PetscCall(MatDestroy(&A));
33
34 PetscCall(PetscFinalize());
35 return 0;
36 }
37
38 /*TEST
39
40 test:
41 output_file: output/empty.out
42
43 TEST*/
44