xref: /petsc/src/mat/tests/ex8.c (revision 9566063d113dddea24716c546802770db7481bc0)
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*9566063dSJacob Faibussowitsch   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
14*9566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL));
15*9566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
16c4762a1bSJed Brown 
17c4762a1bSJed Brown   /* create the matrix for the five point stencil, YET AGAIN */
18*9566063dSJacob Faibussowitsch   PetscCall(MatCreate(PETSC_COMM_SELF,&C));
19*9566063dSJacob Faibussowitsch   PetscCall(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n));
20*9566063dSJacob Faibussowitsch   PetscCall(MatSetFromOptions(C));
21*9566063dSJacob Faibussowitsch   PetscCall(MatSetUp(C));
22c4762a1bSJed Brown   for (i=0; i<m; i++) {
23c4762a1bSJed Brown     for (j=0; j<n; j++) {
24c4762a1bSJed Brown       v = -1.0;  Ii = j + n*i;
25*9566063dSJacob Faibussowitsch       if (i>0)   {J=Ii-n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
26*9566063dSJacob Faibussowitsch       if (i<m-1) {J=Ii+n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
27*9566063dSJacob Faibussowitsch       if (j>0)   {J=Ii-1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
28*9566063dSJacob Faibussowitsch       if (j<n-1) {J=Ii+1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
29*9566063dSJacob Faibussowitsch       v = 4.0; PetscCall(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES));
30c4762a1bSJed Brown     }
31c4762a1bSJed Brown   }
32*9566063dSJacob Faibussowitsch   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
33*9566063dSJacob Faibussowitsch   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
34*9566063dSJacob Faibussowitsch   PetscCall(MatView(C,PETSC_VIEWER_STDOUT_SELF));
35c4762a1bSJed Brown 
36*9566063dSJacob Faibussowitsch   PetscCall(MatGetInfo(C,MAT_LOCAL,&info));
37*9566063dSJacob Faibussowitsch   PetscCall(PetscPrintf(PETSC_COMM_SELF,"matrix nonzeros = %" PetscInt_FMT ", allocated nonzeros = %" PetscInt_FMT "\n",(PetscInt)info.nz_used,(PetscInt)info.nz_allocated));
38c4762a1bSJed Brown 
39*9566063dSJacob Faibussowitsch   PetscCall(MatDestroy(&C));
40*9566063dSJacob Faibussowitsch   PetscCall(PetscFinalize());
41b122ec5aSJacob Faibussowitsch   return 0;
42c4762a1bSJed Brown }
43c4762a1bSJed Brown 
44c4762a1bSJed Brown /*TEST
45c4762a1bSJed Brown 
46c4762a1bSJed Brown    test:
47c4762a1bSJed Brown 
48c4762a1bSJed Brown TEST*/
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