Actual source code: ex64.c
2: static char help[] = "Saves 4by4 block matrix.\n\n";
4: #include <petscmat.h>
6: int main(int argc, char **args)
7: {
8: Mat A;
9: PetscInt i, j;
10: PetscMPIInt size;
11: PetscViewer fd;
12: PetscScalar values[16], one = 1.0;
13: Vec x;
15: PetscFunctionBeginUser;
16: PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
17: PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
18: PetscCheck(size == 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, m "Can only run on one processor");
20: /*
21: Open binary file. Note that we use FILE_MODE_WRITE to indicate
22: writing to this file.
23: */
24: PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD, "4by4", FILE_MODE_WRITE, &fd));
26: PetscCall(MatCreateSeqBAIJ(PETSC_COMM_WORLD, 4, 12, 12, 0, 0, &A));
28: for (i = 0; i < 16; i++) values[i] = i;
29: for (i = 0; i < 4; i++) values[4 * i + i] += 5;
30: i = 0;
31: j = 0;
32: PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));
34: for (i = 0; i < 16; i++) values[i] = i;
35: i = 0;
36: j = 2;
37: PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));
39: for (i = 0; i < 16; i++) values[i] = i;
40: i = 1;
41: j = 0;
42: PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));
44: for (i = 0; i < 16; i++) values[i] = i;
45: for (i = 0; i < 4; i++) values[4 * i + i] += 6;
46: i = 1;
47: j = 1;
48: PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));
50: for (i = 0; i < 16; i++) values[i] = i;
51: i = 2;
52: j = 0;
53: PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));
55: for (i = 0; i < 16; i++) values[i] = i;
56: for (i = 0; i < 4; i++) values[4 * i + i] += 7;
57: i = 2;
58: j = 2;
59: PetscCall(MatSetValuesBlocked(A, 1, &i, 1, &j, values, INSERT_VALUES));
61: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
62: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
63: PetscCall(MatView(A, fd));
64: PetscCall(MatDestroy(&A));
66: PetscCall(VecCreateSeq(PETSC_COMM_WORLD, 12, &x));
67: PetscCall(VecSet(x, one));
68: PetscCall(VecView(x, fd));
69: PetscCall(VecDestroy(&x));
71: PetscCall(PetscViewerDestroy(&fd));
72: PetscCall(PetscFinalize());
73: return 0;
74: }