Actual source code: ex20.c
1: /*$Id: ex20.c,v 1.23 2001/08/07 03:03:07 balay Exp $*/
3: static char help[] = "Tests converting a matrix to another format with MatConvert().\n\n";
5: #include petscmat.h
9: int main(int argc,char **args)
10: {
11: Mat C,A;
12: int i,j,m = 5,n = 4,I,J,ierr,rank,size;
13: PetscScalar v;
14: char mtype[256];
16: PetscInitialize(&argc,&args,(char *)0,help);
17: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
19: /* This example does not work correctly for np > 2 */
20: MPI_Comm_size(PETSC_COMM_WORLD,&size);
21: if (size > 2) SETERRQ(1,"Use np <= 2");
23: /* Create the matrix for the five point stencil, YET AGAIN */
24: MatCreate(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n,&C);
25: MatSetFromOptions(C);
26: for (i=0; i<m; i++) {
27: for (j=2*rank; j<2*rank+2; j++) {
28: v = -1.0; I = j + n*i;
29: if (i>0) {J = I - n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
30: if (i<m-1) {J = I + n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
31: if (j>0) {J = I - 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
32: if (j<n-1) {J = I + 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
33: v = 4.0; MatSetValues(C,1,&I,1,&I,&v,INSERT_VALUES);
34: }
35: }
37: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
38: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
39: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO);
40: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
41: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
42: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
43:
44: PetscStrcpy(mtype,MATSAME);
45: PetscOptionsGetString(PETSC_NULL,"-conv_mat_type",mtype,256,PETSC_NULL);
46: MatConvert(C,mtype,&A);
47: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO);
48: MatView(A,PETSC_VIEWER_STDOUT_WORLD);
49: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
50: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_IMPL);
51: MatView(A,PETSC_VIEWER_STDOUT_WORLD);
53: /* Free data structures */
54: MatDestroy(A);
55: MatDestroy(C);
57: PetscFinalize();
58: return 0;
59: }