Actual source code: ex59.c


  2: static char help[] = "Tests MatCreateSubmatrix() in parallel.";

  4: #include <petscmat.h>

  6: int main(int argc,char **args)
  7: {
  8:   Mat            C,A;
  9:   PetscInt       i,j,m = 3,n = 2,rstart,rend;
 10:   PetscMPIInt    size,rank;
 11:   PetscScalar    v;
 12:   IS             isrow,iscol;

 14:   PetscInitialize(&argc,&args,(char*)0,help);
 15:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
 16:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
 17:   n    = 2*size;

 19:   MatCreate(PETSC_COMM_WORLD,&C);
 20:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);
 21:   MatSetFromOptions(C);
 22:   MatSetUp(C);

 24:   /*
 25:         This is JUST to generate a nice test matrix, all processors fill up
 26:     the entire matrix. This is not something one would ever do in practice.
 27:   */
 28:   MatGetOwnershipRange(C,&rstart,&rend);
 29:   for (i=rstart; i<rend; i++) {
 30:     for (j=0; j<m*n; j++) {
 31:       v    = i + j + 1;
 32:       MatSetValues(C,1,&i,1,&j,&v,INSERT_VALUES);
 33:     }
 34:   }

 36:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
 37:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
 38:   PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_COMMON);
 39:   MatView(C,PETSC_VIEWER_STDOUT_WORLD);

 41:   /*
 42:      Generate a new matrix consisting of every second row and column of
 43:    the original matrix
 44:   */
 45:   MatGetOwnershipRange(C,&rstart,&rend);
 46:   /* Create parallel IS with the rows we want on THIS processor */
 47:   ISCreateStride(PETSC_COMM_WORLD,(rend-rstart)/2,rstart,2,&isrow);
 48:   /* Create parallel IS with the rows we want on THIS processor (same as rows for now) */
 49:   ISCreateStride(PETSC_COMM_WORLD,(rend-rstart)/2,rstart,2,&iscol);

 51:   MatCreateSubMatrix(C,isrow,iscol,MAT_INITIAL_MATRIX,&A);
 52:   MatCreateSubMatrix(C,isrow,iscol,MAT_REUSE_MATRIX,&A);
 53:   MatView(A,PETSC_VIEWER_STDOUT_WORLD);

 55:   ISDestroy(&isrow);
 56:   ISDestroy(&iscol);
 57:   MatDestroy(&A);
 58:   MatDestroy(&C);
 59:   PetscFinalize();
 60:   return 0;
 61: }

 63: /*TEST

 65:    test:

 67:    test:
 68:       suffix: 2
 69:       nsize: 3

 71:    test:
 72:       suffix: 2_baij
 73:       nsize: 3
 74:       args: -mat_type baij

 76:    test:
 77:       suffix: 2_sbaij
 78:       nsize: 3
 79:       args: -mat_type sbaij

 81:    test:
 82:       suffix: baij
 83:       args: -mat_type baij
 84:       output_file: output/ex59_1_baij.out

 86:    test:
 87:       suffix: sbaij
 88:       args: -mat_type sbaij
 89:       output_file: output/ex59_1_sbaij.out

 91: TEST*/