Actual source code: ex3.c


  2: static char help[] = "Tests parallel vector assembly.  Input arguments are\n\
  3:   -n <length> : local vector length\n\n";

  5: #include <petscvec.h>

  7: int main(int argc, char **argv)
  8: {
  9:   PetscMPIInt size, rank;
 10:   PetscInt    n   = 5, idx;
 11:   PetscScalar one = 1.0, two = 2.0, three = 3.0;
 12:   Vec         x, y;

 14:   PetscFunctionBeginUser;
 15:   PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
 16:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
 17:   if (n < 5) n = 5;
 18:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 19:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));

 21:   PetscCheck(size >= 2, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Must be run with at least two processors");

 23:   /* create two vector */
 24:   PetscCall(VecCreateSeq(PETSC_COMM_SELF, n, &x));
 25:   PetscCall(VecCreate(PETSC_COMM_WORLD, &y));
 26:   PetscCall(VecSetSizes(y, n, PETSC_DECIDE));
 27:   PetscCall(VecSetFromOptions(y));
 28:   PetscCall(VecSet(x, one));
 29:   PetscCall(VecSet(y, two));

 31:   if (rank == 1) {
 32:     idx = 2;
 33:     PetscCall(VecSetValues(y, 1, &idx, &three, INSERT_VALUES));
 34:     idx = 0;
 35:     PetscCall(VecSetValues(y, 1, &idx, &two, INSERT_VALUES));
 36:     idx = 0;
 37:     PetscCall(VecSetValues(y, 1, &idx, &one, INSERT_VALUES));
 38:   } else {
 39:     idx = 7;
 40:     PetscCall(VecSetValues(y, 1, &idx, &three, INSERT_VALUES));
 41:   }
 42:   PetscCall(VecAssemblyBegin(y));
 43:   PetscCall(VecAssemblyEnd(y));

 45:   PetscCall(VecView(y, PETSC_VIEWER_STDOUT_WORLD));

 47:   PetscCall(VecDestroy(&x));
 48:   PetscCall(VecDestroy(&y));

 50:   PetscCall(PetscFinalize());
 51:   return 0;
 52: }

 54: /*TEST

 56:      test:
 57:        nsize: 2

 59:      test:
 60:        suffix: 2
 61:        nsize: 2
 62:        args: -vec_view ascii::ascii_info

 64: TEST*/