xref: /petsc/src/mat/tests/ex10.c (revision 9566063d113dddea24716c546802770db7481bc0)
1c4762a1bSJed Brown 
2c4762a1bSJed Brown static char help[] = "Tests repeated use of assembly for matrices.\n\n";
3c4762a1bSJed Brown 
4c4762a1bSJed Brown #include <petscmat.h>
5c4762a1bSJed Brown 
6c4762a1bSJed Brown int main(int argc,char **args)
7c4762a1bSJed Brown {
8c4762a1bSJed Brown   Mat            C;
9c4762a1bSJed Brown   PetscInt       i,j,m = 5,n = 2,Ii,J;
10c4762a1bSJed Brown   PetscMPIInt    rank,size;
11c4762a1bSJed Brown   PetscScalar    v;
12c4762a1bSJed Brown 
13*9566063dSJacob Faibussowitsch   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
14*9566063dSJacob Faibussowitsch   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
15*9566063dSJacob Faibussowitsch   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
16c4762a1bSJed Brown   n    = 2*size;
17c4762a1bSJed Brown 
18c4762a1bSJed Brown   /* create the matrix for the five point stencil, YET AGAIN*/
19*9566063dSJacob Faibussowitsch   PetscCall(MatCreate(PETSC_COMM_WORLD,&C));
20*9566063dSJacob Faibussowitsch   PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n));
21*9566063dSJacob Faibussowitsch   PetscCall(MatSetFromOptions(C));
22*9566063dSJacob Faibussowitsch   PetscCall(MatSetUp(C));
23c4762a1bSJed Brown   for (i=0; i<m; i++) {
24c4762a1bSJed Brown     for (j=2*rank; j<2*rank+2; j++) {
25c4762a1bSJed Brown       v = -1.0;  Ii = j + n*i;
26*9566063dSJacob Faibussowitsch       if (i>0)   {J = Ii - n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
27*9566063dSJacob Faibussowitsch       if (i<m-1) {J = Ii + n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
28*9566063dSJacob Faibussowitsch       if (j>0)   {J = Ii - 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
29*9566063dSJacob Faibussowitsch       if (j<n-1) {J = Ii + 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
30*9566063dSJacob Faibussowitsch       v = 4.0; PetscCall(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES));
31c4762a1bSJed Brown     }
32c4762a1bSJed Brown   }
33*9566063dSJacob Faibussowitsch   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
34*9566063dSJacob Faibussowitsch   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
35c4762a1bSJed Brown   for (i=0; i<m; i++) {
36c4762a1bSJed Brown     for (j=2*rank; j<2*rank+2; j++) {
37c4762a1bSJed Brown       v = 1.0;  Ii = j + n*i;
38*9566063dSJacob Faibussowitsch       if (i>0)   {J = Ii - n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
39*9566063dSJacob Faibussowitsch       if (i<m-1) {J = Ii + n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
40*9566063dSJacob Faibussowitsch       if (j>0)   {J = Ii - 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
41*9566063dSJacob Faibussowitsch       if (j<n-1) {J = Ii + 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
42*9566063dSJacob Faibussowitsch       v = -4.0; PetscCall(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES));
43c4762a1bSJed Brown     }
44c4762a1bSJed Brown   }
45*9566063dSJacob Faibussowitsch   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
46*9566063dSJacob Faibussowitsch   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
47c4762a1bSJed Brown 
48*9566063dSJacob Faibussowitsch   PetscCall(MatView(C,PETSC_VIEWER_STDOUT_WORLD));
49c4762a1bSJed Brown 
50*9566063dSJacob Faibussowitsch   PetscCall(MatDestroy(&C));
51*9566063dSJacob Faibussowitsch   PetscCall(PetscFinalize());
52b122ec5aSJacob Faibussowitsch   return 0;
53c4762a1bSJed Brown }
54c4762a1bSJed Brown 
55c4762a1bSJed Brown /*TEST
56c4762a1bSJed Brown 
57c4762a1bSJed Brown    test:
58c4762a1bSJed Brown 
59c4762a1bSJed Brown TEST*/
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