2: static char help[] = "Saves a rectangular sparse matrix to disk.\n\n";

  4: #include <petscmat.h>

  6: int main(int argc,char **args)
  7: {
  8:   Mat            A;
 10:   PetscInt       m = 100,n = 11,js[11],i,j,cnt;
 11:   PetscScalar    values[11];
 12:   PetscViewer    view;

 14:   PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
 15:   MatCreateSeqAIJ(PETSC_COMM_WORLD,m,n,20,0,&A);

 17:   for (i=0; i<n; i++) values[i] = (PetscReal)i;

 19:   for (i=0; i<m; i++) {
 20:     cnt = 0;
 21:     if (i % 2) {
 22:       for (j=0; j<n; j += 2) {
 23:         js[cnt++] = j;
 24:       }
 25:     } else {
 26:       ;
 27:     }
 28:     MatSetValues(A,1,&i,cnt,js,values,INSERT_VALUES);
 29:   }
 30:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 31:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 33:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,"rect",FILE_MODE_WRITE,&view);
 34:   MatView(A,view);
 35:   PetscViewerDestroy(&view);

 37:   MatDestroy(&A);

 39:   PetscFinalize();
 40:   return ierr;
 41: }



 45: /*TEST

 47:    test:

 49: TEST*/