xref: /petsc/src/mat/tests/ex10.c (revision 030f984af8d8bb4c203755d35bded3c05b3d83ce)
1 
2 static char help[] = "Tests repeated use of assembly for matrices.\n\n";
3 
4 #include <petscmat.h>
5 
6 int main(int argc,char **args)
7 {
8   Mat            C;
9   PetscInt       i,j,m = 5,n = 2,Ii,J;
10   PetscErrorCode ierr;
11   PetscMPIInt    rank,size;
12   PetscScalar    v;
13 
14   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
15   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr);
16   ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRMPI(ierr);
17   n    = 2*size;
18 
19   /* create the matrix for the five point stencil, YET AGAIN*/
20   ierr = MatCreate(PETSC_COMM_WORLD,&C);CHKERRQ(ierr);
21   ierr = MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);CHKERRQ(ierr);
22   ierr = MatSetFromOptions(C);CHKERRQ(ierr);
23   ierr = MatSetUp(C);CHKERRQ(ierr);
24   for (i=0; i<m; i++) {
25     for (j=2*rank; j<2*rank+2; j++) {
26       v = -1.0;  Ii = j + n*i;
27       if (i>0)   {J = Ii - n; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
28       if (i<m-1) {J = Ii + n; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
29       if (j>0)   {J = Ii - 1; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
30       if (j<n-1) {J = Ii + 1; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
31       v = 4.0; ierr = MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES);CHKERRQ(ierr);
32     }
33   }
34   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
35   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
36   for (i=0; i<m; i++) {
37     for (j=2*rank; j<2*rank+2; j++) {
38       v = 1.0;  Ii = j + n*i;
39       if (i>0)   {J = Ii - n; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
40       if (i<m-1) {J = Ii + n; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
41       if (j>0)   {J = Ii - 1; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
42       if (j<n-1) {J = Ii + 1; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
43       v = -4.0; ierr = MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES);CHKERRQ(ierr);
44     }
45   }
46   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
47   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
48 
49   ierr = MatView(C,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
50 
51   ierr = MatDestroy(&C);CHKERRQ(ierr);
52   ierr = PetscFinalize();
53   return ierr;
54 }
55 
56 /*TEST
57 
58    test:
59 
60 TEST*/
61