xref: /petsc/src/mat/tests/ex8.c (revision 327415f76d85372a4417cf1aaa14db707d4d6c04)
1c4762a1bSJed Brown 
2c4762a1bSJed Brown static char help[] = "Tests automatic allocation of matrix storage space.\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 = 3,n = 3,Ii,J;
10c4762a1bSJed Brown   PetscScalar    v;
11c4762a1bSJed Brown   MatInfo        info;
12c4762a1bSJed Brown 
13*327415f7SBarry Smith   PetscFunctionBeginUser;
149566063dSJacob Faibussowitsch   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
159566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL));
169566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
17c4762a1bSJed Brown 
18c4762a1bSJed Brown   /* create the matrix for the five point stencil, YET AGAIN */
199566063dSJacob Faibussowitsch   PetscCall(MatCreate(PETSC_COMM_SELF,&C));
209566063dSJacob Faibussowitsch   PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n));
219566063dSJacob Faibussowitsch   PetscCall(MatSetFromOptions(C));
229566063dSJacob Faibussowitsch   PetscCall(MatSetUp(C));
23c4762a1bSJed Brown   for (i=0; i<m; i++) {
24c4762a1bSJed Brown     for (j=0; j<n; j++) {
25c4762a1bSJed Brown       v = -1.0;  Ii = j + n*i;
269566063dSJacob Faibussowitsch       if (i>0)   {J=Ii-n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
279566063dSJacob Faibussowitsch       if (i<m-1) {J=Ii+n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
289566063dSJacob Faibussowitsch       if (j>0)   {J=Ii-1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
299566063dSJacob Faibussowitsch       if (j<n-1) {J=Ii+1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
309566063dSJacob Faibussowitsch       v = 4.0; PetscCall(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES));
31c4762a1bSJed Brown     }
32c4762a1bSJed Brown   }
339566063dSJacob Faibussowitsch   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
349566063dSJacob Faibussowitsch   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
359566063dSJacob Faibussowitsch   PetscCall(MatView(C,PETSC_VIEWER_STDOUT_SELF));
36c4762a1bSJed Brown 
379566063dSJacob Faibussowitsch   PetscCall(MatGetInfo(C,MAT_LOCAL,&info));
389566063dSJacob Faibussowitsch   PetscCall(PetscPrintf(PETSC_COMM_SELF,"matrix nonzeros = %" PetscInt_FMT ", allocated nonzeros = %" PetscInt_FMT "\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated));
39c4762a1bSJed Brown 
409566063dSJacob Faibussowitsch   PetscCall(MatDestroy(&C));
419566063dSJacob Faibussowitsch   PetscCall(PetscFinalize());
42b122ec5aSJacob Faibussowitsch   return 0;
43c4762a1bSJed Brown }
44c4762a1bSJed Brown 
45c4762a1bSJed Brown /*TEST
46c4762a1bSJed Brown 
47c4762a1bSJed Brown    test:
48c4762a1bSJed Brown 
49c4762a1bSJed Brown TEST*/
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