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];
15: PetscInitialize(&argc,&args,(char*)0,help);
16: /* Create vectors */
17: VecCreateSeq(PETSC_COMM_SELF,n,&b);
18: VecCreateSeq(PETSC_COMM_SELF,n,&u);
20: /* Create and assemble matrix */
21: MatCreateSeqDense(PETSC_COMM_SELF,n,n,NULL,&mat);
22: value[0] = -1.0; value[1] = 2.0; value[2] = -1.0;
23: for (i=1; i<n-1; i++) {
24: col[0] = i-1; col[1] = i; col[2] = i+1;
25: MatSetValues(mat,1,&i,3,col,value,INSERT_VALUES);
26: }
27: i = n - 1; col[0] = n - 2; col[1] = n - 1;
28: MatSetValues(mat,1,&i,2,col,value,INSERT_VALUES);
29: i = 0; col[0] = 0; col[1] = 1; value[0] = 2.0; value[1] = -1.0;
30: MatSetValues(mat,1,&i,2,col,value,INSERT_VALUES);
31: MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);
32: MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);
34: /* Create PC context and set up data structures */
35: PCCreate(PETSC_COMM_WORLD,&pc);
36: PCSetType(pc,PCSOR);
37: PCSetFromOptions(pc);
38: PCSetOperators(pc,mat,mat);
39: PCSetUp(pc);
41: value[0] = 1.0;
42: for (i=0; i<n; i++) {
43: VecSet(u,0.0);
44: VecSetValues(u,1,&i,value,INSERT_VALUES);
45: VecAssemblyBegin(u);
46: VecAssemblyEnd(u);
47: PCApply(pc,u,b);
48: VecView(b,PETSC_VIEWER_STDOUT_SELF);
49: }
51: /* Free data structures */
52: MatDestroy(&mat);
53: PCDestroy(&pc);
54: VecDestroy(&u);
55: VecDestroy(&b);
56: PetscFinalize();
57: return 0;
58: }
60: /*TEST
62: test:
64: TEST*/