Actual source code: ex8.c
2: static char help[] = "Tests automatic allocation of matrix storage space.\n\n";
4: #include <petscmat.h>
6: int main(int argc,char **args)
7: {
8: Mat C;
9: PetscInt i,j,m = 3,n = 3,Ii,J;
10: PetscScalar v;
11: MatInfo info;
13: PetscInitialize(&argc,&args,(char*)0,help);
14: PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
15: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
17: /* create the matrix for the five point stencil, YET AGAIN */
18: MatCreate(PETSC_COMM_SELF,&C);
19: MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);
20: MatSetFromOptions(C);
21: MatSetUp(C);
22: for (i=0; i<m; i++) {
23: for (j=0; j<n; j++) {
24: v = -1.0; Ii = j + n*i;
25: if (i>0) {J=Ii-n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
26: if (i<m-1) {J=Ii+n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
27: if (j>0) {J=Ii-1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
28: if (j<n-1) {J=Ii+1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
29: v = 4.0; MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES);
30: }
31: }
32: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
33: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
34: MatView(C,PETSC_VIEWER_STDOUT_SELF);
36: MatGetInfo(C,MAT_LOCAL,&info);
37: PetscPrintf(PETSC_COMM_SELF,"matrix nonzeros = %" PetscInt_FMT ", allocated nonzeros = %" PetscInt_FMT "\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated);
39: MatDestroy(&C);
40: PetscFinalize();
41: return 0;
42: }
44: /*TEST
46: test:
48: TEST*/