1: static char help[] = "Tests DMDAGlobalToNaturalAllCreate() using contour plotting for 2d DMDAs.\n\n";

  3: #include <petscdm.h>
  4: #include <petscdmda.h>

  6: int main(int argc, char **argv)
  7: {
  8:   PetscInt        i, j, M = 10, N = 8, m = PETSC_DECIDE, n = PETSC_DECIDE;
  9:   PetscMPIInt     rank;
 10:   PetscBool       flg = PETSC_FALSE;
 11:   DM              da;
 12:   PetscViewer     viewer;
 13:   Vec             localall, global;
 14:   PetscScalar     value, *vlocal;
 15:   DMBoundaryType  bx = DM_BOUNDARY_NONE, by = DM_BOUNDARY_NONE;
 16:   DMDAStencilType stype = DMDA_STENCIL_BOX;
 17:   VecScatter      tolocalall, fromlocalall;
 18:   PetscInt        start, end;

 20:   PetscFunctionBeginUser;
 21:   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
 22:   PetscCall(PetscViewerDrawOpen(PETSC_COMM_WORLD, NULL, "", 300, 0, 300, 300, &viewer));

 24:   /* Read options */
 25:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-M", &M, NULL));
 26:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-N", &N, NULL));
 27:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-m", &m, NULL));
 28:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
 29:   PetscCall(PetscOptionsGetBool(NULL, NULL, "-star_stencil", &flg, NULL));
 30:   if (flg) stype = DMDA_STENCIL_STAR;

 32:   /* Create distributed array and get vectors */
 33:   PetscCall(DMDACreate2d(PETSC_COMM_WORLD, bx, by, stype, M, N, m, n, 1, 1, NULL, NULL, &da));
 34:   PetscCall(DMSetFromOptions(da));
 35:   PetscCall(DMSetUp(da));

 37:   PetscCall(DMCreateGlobalVector(da, &global));
 38:   PetscCall(VecCreateSeq(PETSC_COMM_SELF, M * N, &localall));

 40:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
 41:   PetscCall(VecGetOwnershipRange(global, &start, &end));
 42:   for (i = start; i < end; i++) {
 43:     value = 5.0 * rank;
 44:     PetscCall(VecSetValues(global, 1, &i, &value, INSERT_VALUES));
 45:   }
 46:   PetscCall(VecAssemblyBegin(global));
 47:   PetscCall(VecAssemblyEnd(global));
 48:   PetscCall(VecView(global, viewer));

 50:   /*
 51:      Create Scatter from global DMDA parallel vector to local vector that
 52:    contains all entries
 53:   */
 54:   PetscCall(DMDAGlobalToNaturalAllCreate(da, &tolocalall));
 55:   PetscCall(DMDANaturalAllToGlobalCreate(da, &fromlocalall));

 57:   PetscCall(VecScatterBegin(tolocalall, global, localall, INSERT_VALUES, SCATTER_FORWARD));
 58:   PetscCall(VecScatterEnd(tolocalall, global, localall, INSERT_VALUES, SCATTER_FORWARD));

 60:   PetscCall(VecGetArray(localall, &vlocal));
 61:   for (j = 0; j < N; j++) {
 62:     for (i = 0; i < M; i++) *vlocal++ += i + j * M;
 63:   }
 64:   PetscCall(VecRestoreArray(localall, &vlocal));

 66:   /* scatter back to global vector */
 67:   PetscCall(VecScatterBegin(fromlocalall, localall, global, INSERT_VALUES, SCATTER_FORWARD));
 68:   PetscCall(VecScatterEnd(fromlocalall, localall, global, INSERT_VALUES, SCATTER_FORWARD));

 70:   PetscCall(VecView(global, viewer));

 72:   /* Free memory */
 73:   PetscCall(VecScatterDestroy(&tolocalall));
 74:   PetscCall(VecScatterDestroy(&fromlocalall));
 75:   PetscCall(PetscViewerDestroy(&viewer));
 76:   PetscCall(VecDestroy(&localall));
 77:   PetscCall(VecDestroy(&global));
 78:   PetscCall(DMDestroy(&da));
 79:   PetscCall(PetscFinalize());
 80:   return 0;
 81: }

 83: /*TEST

 85:    build:
 86:      requires: !complex

 88:    test:
 89:       nsize: 3
 90:       output_file: output/empty.out

 92: TEST*/