Actual source code: ex20.c
2: static char help[] = "Tests converting a matrix to another format with MatConvert().\n\n";
4: #include petscmat.h
8: int main(int argc,char **args)
9: {
10: Mat C,A = PETSC_NULL;
11: PetscInt i,j,m = 5,n = 4,I,J;
12: PetscErrorCode ierr;
13: PetscMPIInt rank,size;
14: PetscScalar v;
15: char mtype[256];
17: PetscInitialize(&argc,&args,(char *)0,help);
18: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
20: /* This example does not work correctly for np > 2 */
21: MPI_Comm_size(PETSC_COMM_WORLD,&size);
22: if (size > 2) SETERRQ(1,"Use np <= 2");
24: /* Create the matrix for the five point stencil, YET AGAIN */
25: MatCreate(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n,&C);
26: MatSetFromOptions(C);
27: for (i=0; i<m; i++) {
28: for (j=2*rank; j<2*rank+2; j++) {
29: v = -1.0; I = j + n*i;
30: if (i>0) {J = I - n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
31: if (i<m-1) {J = I + n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
32: if (j>0) {J = I - 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
33: if (j<n-1) {J = I + 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
34: v = 4.0; MatSetValues(C,1,&I,1,&I,&v,INSERT_VALUES);
35: }
36: }
38: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
39: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
40: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO);
41: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
42: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
43: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
44:
45: PetscStrcpy(mtype,MATSAME);
46: PetscOptionsGetString(PETSC_NULL,"-conv_mat_type",mtype,256,PETSC_NULL);
47: MatConvert(C,mtype,&A);
48: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO);
49: MatView(A,PETSC_VIEWER_STDOUT_WORLD);
50: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
51: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_IMPL);
52: MatView(A,PETSC_VIEWER_STDOUT_WORLD);
54: /* Free data structures */
55: MatDestroy(A);
56: MatDestroy(C);
58: PetscFinalize();
59: return 0;
60: }