Actual source code: ex124.c
1: static char help[] = "Check the difference of the two matrices \n\
2: Reads PETSc matrix A and B, then check B=A-B \n\
3: Input parameters include\n\
4: -fA <input_file> -fB <input_file> \n\n";
6: #include <petscmat.h>
8: int main(int argc, char **args)
9: {
10: Mat A, B;
11: PetscViewer fd;
12: char file[2][PETSC_MAX_PATH_LEN];
13: PetscBool flg;
14: PetscMPIInt size;
15: PetscInt ma, na, mb, nb;
18: PetscInitialize(&argc, &args, (char *)0, help);
19: MPI_Comm_size(PETSC_COMM_WORLD, &size);
22: /* read the two matrices, A and B */
23: PetscOptionsGetString(NULL, NULL, "-fA", file[0], sizeof(file[0]), &flg);
25: PetscOptionsGetString(NULL, NULL, "-fB", file[1], sizeof(file[1]), &flg);
28: /* Load matrices */
29: PetscViewerBinaryOpen(PETSC_COMM_WORLD, file[0], FILE_MODE_READ, &fd);
30: MatCreate(PETSC_COMM_WORLD, &A);
31: MatLoad(A, fd);
32: PetscViewerDestroy(&fd);
33: printf("\n A:\n");
34: printf("----------------------\n");
35: MatView(A, PETSC_VIEWER_STDOUT_WORLD);
36: MatGetSize(A, &ma, &na);
38: PetscViewerBinaryOpen(PETSC_COMM_WORLD, file[1], FILE_MODE_READ, &fd);
39: MatCreate(PETSC_COMM_WORLD, &B);
40: MatLoad(B, fd);
41: PetscViewerDestroy(&fd);
42: printf("\n B:\n");
43: printf("----------------------\n");
44: MatView(B, PETSC_VIEWER_STDOUT_WORLD);
45: MatGetSize(B, &mb, &nb);
47: /* Compute B = -A + B */
49: MatAXPY(B, -1.0, A, DIFFERENT_NONZERO_PATTERN);
50: printf("\n B - A:\n");
51: printf("----------------------\n");
52: MatView(B, PETSC_VIEWER_STDOUT_WORLD);
54: MatDestroy(&B);
55: MatDestroy(&A);
56: PetscFinalize();
57: return 0;
58: }