xref: /petsc/src/dm/tests/ex4.c (revision 609caa7c8c030312b00807b4f015fd827bb80932)

static char help[] = "Tests various 2-dimensional DMDA routines.\n\n";

#include <petscdm.h>
#include <petscdmda.h>

int main(int argc, char **argv)
{
  PetscMPIInt     rank;
  PetscInt        M = 10, N = 8, m = PETSC_DECIDE;
  PetscInt        s = 2, w = 2, n = PETSC_DECIDE, nloc, l, i, j, kk;
  PetscInt        Xs, Xm, Ys, Ym, iloc, *iglobal;
  const PetscInt *ltog;
  PetscInt       *lx = NULL, *ly = NULL;
  PetscBool       testorder = PETSC_FALSE, flg;
  DMBoundaryType  bx = DM_BOUNDARY_NONE, by = DM_BOUNDARY_NONE;
  DM              da;
  PetscViewer     viewer;
  Vec             local, global;
  PetscScalar     value;
  DMDAStencilType st = DMDA_STENCIL_BOX;
  AO              ao;

  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &argv, NULL, help));
  PetscCall(PetscViewerDrawOpen(PETSC_COMM_WORLD, 0, "", 300, 0, 400, 400, &viewer));

  /* Readoptions */
  PetscCall(PetscOptionsGetInt(NULL, NULL, "-NX", &M, NULL));
  PetscCall(PetscOptionsGetInt(NULL, NULL, "-NY", &N, NULL));
  PetscCall(PetscOptionsGetInt(NULL, NULL, "-m", &m, NULL));
  PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
  PetscCall(PetscOptionsGetInt(NULL, NULL, "-s", &s, NULL));
  PetscCall(PetscOptionsGetInt(NULL, NULL, "-w", &w, NULL));

  flg = PETSC_FALSE;
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-xperiodic", &flg, NULL));
  if (flg) bx = DM_BOUNDARY_PERIODIC;
  flg = PETSC_FALSE;
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-yperiodic", &flg, NULL));
  if (flg) by = DM_BOUNDARY_PERIODIC;
  flg = PETSC_FALSE;
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-xghosted", &flg, NULL));
  if (flg) bx = DM_BOUNDARY_GHOSTED;
  flg = PETSC_FALSE;
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-yghosted", &flg, NULL));
  if (flg) by = DM_BOUNDARY_GHOSTED;
  flg = PETSC_FALSE;
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-star", &flg, NULL));
  if (flg) st = DMDA_STENCIL_STAR;
  flg = PETSC_FALSE;
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-box", &flg, NULL));
  if (flg) st = DMDA_STENCIL_BOX;
  flg = PETSC_FALSE;
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-testorder", &testorder, NULL));
  /*
      Test putting two nodes in x and y on each processor, exact last processor
      in x and y gets the rest.
  */
  flg = PETSC_FALSE;
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-distribute", &flg, NULL));
  if (flg) {
    PetscCheck(m != PETSC_DECIDE, PETSC_COMM_WORLD, PETSC_ERR_USER_INPUT, "Must set -m option with -distribute option");
    PetscCall(PetscMalloc1(m, &lx));
    for (i = 0; i < m - 1; i++) lx[i] = 4;
    lx[m - 1] = M - 4 * (m - 1);
    PetscCheck(n != PETSC_DECIDE, PETSC_COMM_WORLD, PETSC_ERR_USER_INPUT, "Must set -n option with -distribute option");
    PetscCall(PetscMalloc1(n, &ly));
    for (i = 0; i < n - 1; i++) ly[i] = 2;
    ly[n - 1] = N - 2 * (n - 1);
  }

  /* Create distributed array and get vectors */
  PetscCall(DMDACreate2d(PETSC_COMM_WORLD, bx, by, st, M, N, m, n, w, s, lx, ly, &da));
  PetscCall(DMSetFromOptions(da));
  PetscCall(DMSetUp(da));
  PetscCall(PetscFree(lx));
  PetscCall(PetscFree(ly));

  PetscCall(DMView(da, viewer));
  PetscCall(DMCreateGlobalVector(da, &global));
  PetscCall(DMCreateLocalVector(da, &local));

  /* Set global vector; send ghost points to local vectors */
  value = 1;
  PetscCall(VecSet(global, value));
  PetscCall(DMGlobalToLocalBegin(da, global, INSERT_VALUES, local));
  PetscCall(DMGlobalToLocalEnd(da, global, INSERT_VALUES, local));

  /* Scale local vectors according to processor rank; pass to global vector */
  PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
  value = rank;
  PetscCall(VecScale(local, value));
  PetscCall(DMLocalToGlobalBegin(da, local, INSERT_VALUES, global));
  PetscCall(DMLocalToGlobalEnd(da, local, INSERT_VALUES, global));

  if (!testorder) { /* turn off printing when testing ordering mappings */
    PetscCall(PetscPrintf(PETSC_COMM_WORLD, "\nGlobal Vectors:\n"));
    PetscCall(VecView(global, PETSC_VIEWER_STDOUT_WORLD));
    PetscCall(PetscPrintf(PETSC_COMM_WORLD, "\n\n"));
  }

  /* Send ghost points to local vectors */
  PetscCall(DMGlobalToLocalBegin(da, global, INSERT_VALUES, local));
  PetscCall(DMGlobalToLocalEnd(da, global, INSERT_VALUES, local));

  flg = PETSC_FALSE;
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-local_print", &flg, NULL));
  if (flg) {
    PetscViewer sviewer;

    PetscCall(PetscViewerASCIIPushSynchronized(PETSC_VIEWER_STDOUT_WORLD));
    PetscCall(PetscSynchronizedPrintf(PETSC_COMM_WORLD, "\nLocal Vector: processor %d\n", rank));
    PetscCall(PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer));
    PetscCall(VecView(local, sviewer));
    PetscCall(PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer));
    PetscCall(PetscViewerASCIIPopSynchronized(PETSC_VIEWER_STDOUT_WORLD));
  }

  /* Tests mappings between application/PETSc orderings */
  if (testorder) {
    ISLocalToGlobalMapping ltogm;

    PetscCall(DMGetLocalToGlobalMapping(da, &ltogm));
    PetscCall(ISLocalToGlobalMappingGetSize(ltogm, &nloc));
    PetscCall(ISLocalToGlobalMappingGetIndices(ltogm, &ltog));
    PetscCall(DMDAGetGhostCorners(da, &Xs, &Ys, NULL, &Xm, &Ym, NULL));
    PetscCall(DMDAGetAO(da, &ao));
    PetscCall(PetscMalloc1(nloc, &iglobal));

    /* Set iglobal to be global indices for each processor's local and ghost nodes,
       using the DMDA ordering of grid points */
    kk = 0;
    for (j = Ys; j < Ys + Ym; j++) {
      for (i = Xs; i < Xs + Xm; i++) {
        iloc = w * ((j - Ys) * Xm + i - Xs);
        for (l = 0; l < w; l++) iglobal[kk++] = ltog[iloc + l];
      }
    }

    /* Map this to the application ordering (which for DMDAs is just the natural ordering
       that would be used for 1 processor, numbering most rapidly by x, then y) */
    PetscCall(AOPetscToApplication(ao, nloc, iglobal));

    /* Then map the application ordering back to the PETSc DMDA ordering */
    PetscCall(AOApplicationToPetsc(ao, nloc, iglobal));

    /* Verify the mappings */
    kk = 0;
    for (j = Ys; j < Ys + Ym; j++) {
      for (i = Xs; i < Xs + Xm; i++) {
        iloc = w * ((j - Ys) * Xm + i - Xs);
        for (l = 0; l < w; l++) {
          if (iglobal[kk] != ltog[iloc + l]) {
            PetscCall(PetscFPrintf(PETSC_COMM_SELF, stdout, "[%d] Problem with mapping: j=%" PetscInt_FMT ", i=%" PetscInt_FMT ", l=%" PetscInt_FMT ", petsc1=%" PetscInt_FMT ", petsc2=%" PetscInt_FMT "\n", rank, j, i, l, ltog[iloc + l], iglobal[kk]));
          }
          kk++;
        }
      }
    }
    PetscCall(PetscFree(iglobal));
    PetscCall(ISLocalToGlobalMappingRestoreIndices(ltogm, &ltog));
  }

  /* Free memory */
  PetscCall(PetscViewerDestroy(&viewer));
  PetscCall(VecDestroy(&local));
  PetscCall(VecDestroy(&global));
  PetscCall(DMDestroy(&da));

  PetscCall(PetscFinalize());
  return 0;
}

/*TEST

   test:
      nsize: 4
      args: -nox
      filter: grep -v -i Object
      requires: x

   test:
      suffix: 2
      args: -testorder -nox
      requires: x
      output_file: output/empty.out

TEST*/