Actual source code: ex4.c
2: static char help[] = "Demonstrates the use of fast Richardson for SOR. And tests\n\
3: the MatSOR() routines.\n\n";
5: #include <petscpc.h>
7: int main(int argc, char **args)
8: {
9: Mat mat;
10: Vec b, u;
11: PC pc;
12: PetscInt n = 5, i, col[3];
13: PetscScalar value[3];
16: PetscInitialize(&argc, &args, (char *)0, help);
17: /* Create vectors */
18: VecCreateSeq(PETSC_COMM_SELF, n, &b);
19: VecCreateSeq(PETSC_COMM_SELF, n, &u);
21: /* Create and assemble matrix */
22: MatCreateSeqDense(PETSC_COMM_SELF, n, n, NULL, &mat);
23: value[0] = -1.0;
24: value[1] = 2.0;
25: value[2] = -1.0;
26: for (i = 1; i < n - 1; i++) {
27: col[0] = i - 1;
28: col[1] = i;
29: col[2] = i + 1;
30: MatSetValues(mat, 1, &i, 3, col, value, INSERT_VALUES);
31: }
32: i = n - 1;
33: col[0] = n - 2;
34: col[1] = n - 1;
35: MatSetValues(mat, 1, &i, 2, col, value, INSERT_VALUES);
36: i = 0;
37: col[0] = 0;
38: col[1] = 1;
39: value[0] = 2.0;
40: value[1] = -1.0;
41: MatSetValues(mat, 1, &i, 2, col, value, INSERT_VALUES);
42: MatAssemblyBegin(mat, MAT_FINAL_ASSEMBLY);
43: MatAssemblyEnd(mat, MAT_FINAL_ASSEMBLY);
45: /* Create PC context and set up data structures */
46: PCCreate(PETSC_COMM_WORLD, &pc);
47: PCSetType(pc, PCSOR);
48: PCSetFromOptions(pc);
49: PCSetOperators(pc, mat, mat);
50: PCSetUp(pc);
52: value[0] = 1.0;
53: for (i = 0; i < n; i++) {
54: VecSet(u, 0.0);
55: VecSetValues(u, 1, &i, value, INSERT_VALUES);
56: VecAssemblyBegin(u);
57: VecAssemblyEnd(u);
58: PCApply(pc, u, b);
59: VecView(b, PETSC_VIEWER_STDOUT_SELF);
60: }
62: /* Free data structures */
63: MatDestroy(&mat);
64: PCDestroy(&pc);
65: VecDestroy(&u);
66: VecDestroy(&b);
67: PetscFinalize();
68: return 0;
69: }
71: /*TEST
73: test:
75: TEST*/