Actual source code: ex6.c
1: /*$Id: ex6.c,v 1.18 2001/08/07 03:03:07 balay Exp $*/
3: static char help[] = "Tests reordering a matrix.nn";
5: #include petscmat.h
7: int main(int argc,char **args)
8: {
9: Mat C;
10: int i,j,m = 5,n = 5,I,J,ierr;
11: PetscScalar v;
12: IS perm,iperm;
14: PetscInitialize(&argc,&args,(char *)0,help);
16: MatCreate(PETSC_COMM_SELF,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n,&C);
17: MatSetFromOptions(C);
19: /* create the matrix for the five point stencil, YET AGAIN*/
20: for (i=0; i<m; i++) {
21: for (j=0; j<n; j++) {
22: v = -1.0; I = j + n*i;
23: if (i>0) {J = I - n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
24: if (i<m-1) {J = I + n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
25: if (j>0) {J = I - 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
26: if (j<n-1) {J = I + 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
27: v = 4.0; MatSetValues(C,1,&I,1,&I,&v,INSERT_VALUES);
28: }
29: }
30: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
31: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
33: MatGetOrdering(C,MATORDERING_ND,&perm,&iperm);
34: ISView(perm,PETSC_VIEWER_STDOUT_SELF);
35: ISView(iperm,PETSC_VIEWER_STDOUT_SELF);
36: MatView(C,PETSC_VIEWER_STDOUT_SELF);
38: ISDestroy(perm);
39: ISDestroy(iperm);
40: MatDestroy(C);
41: PetscFinalize();
42: return 0;
43: }