Actual source code: ex14.c
2: static char help[] = "Tests sequential and parallel MatGetRow() and MatRestoreRow().\n";
4: #include petscmat.h
8: int main(int argc,char **args)
9: {
10: Mat C;
11: PetscInt i,j,m = 5,n = 5,I,J,nz,rstart,rend;
12: PetscErrorCode ierr;
13: PetscMPIInt rank;
14: const PetscInt *idx;
15: PetscScalar v;
16: const PetscScalar *values;
18: PetscInitialize(&argc,&args,(char *)0,help);
20: /* Create the matrix for the five point stencil, YET AGAIN */
21: MatCreate(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n,&C);
22: MatSetFromOptions(C);
23: for (i=0; i<m; i++) {
24: for (j=0; j<n; j++) {
25: v = -1.0; I = j + n*i;
26: if (i>0) {J = I - n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
27: if (i<m-1) {J = I + n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
28: if (j>0) {J = I - 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
29: if (j<n-1) {J = I + 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
30: v = 4.0; MatSetValues(C,1,&I,1,&I,&v,INSERT_VALUES);
31: }
32: }
33: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
34: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
35: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
37: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
38: MatGetOwnershipRange(C,&rstart,&rend);
39: for (i=rstart; i<rend; i++){
40: MatGetRow(C,i,&nz,&idx,&values);
41: if (!rank){
42: #if defined(PETSC_USE_COMPLEX)
43: for (j=0; j<nz; j++) {
44: PetscPrintf(PETSC_COMM_SELF,"%D %g ",idx[j],PetscRealPart(values[j]));
45: }
46: #else
47: for (j=0; j<nz; j++) {
48: PetscPrintf(PETSC_COMM_SELF,"%D %g ",idx[j],values[j]);}
49: #endif
50: PetscPrintf(PETSC_COMM_SELF,"\n");
51: }
52: MatRestoreRow(C,i,&nz,&idx,&values);
53: }
55: MatDestroy(C);
56: PetscFinalize();
57: return 0;
58: }