petscSf.c

static const char help[] = "Test overlapped communication on a single star forest (PetscSF)\n\n";

#include <petscvec.h>
#include <petscsf.h>
#include <petscviewer.h>

int main(int argc, char **argv)
{
    PetscSF      sf;
    Vec          A, Aout;
    Vec          B, Bout;
    PetscScalar *bufA;
    PetscScalar *bufAout;
    PetscScalar *bufB;
    PetscScalar *bufBout;
    PetscMPIInt  rank, size;
    PetscInt     nroots, nleaves;
    PetscInt     i;
    PetscInt    *ilocal;
    PetscSFNode *iremote;

    PetscFunctionBeginUser;
    PetscCall(PetscInitialize(&argc, &argv, NULL, help));
    PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
    PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));

    PetscCheck(size == 2, PETSC_COMM_WORLD, PETSC_ERR_USER, "Only coded for two MPI processes");

    PetscCall(PetscSFCreate(PETSC_COMM_WORLD, &sf));
    PetscCall(PetscSFSetFromOptions(sf));

    nleaves = 2;
    nroots  = 1;
    PetscCall(PetscMalloc1(nleaves, &ilocal));

    for (i = 0; i < nleaves; i++) ilocal[i] = i;

    PetscCall(PetscMalloc1(nleaves, &iremote));
    if (rank == 0) {
        iremote[0].rank  = 0;
        iremote[0].index = 0;
        iremote[1].rank  = 1;
        iremote[1].index = 0;
    } else {
        iremote[0].rank  = 1;
        iremote[0].index = 0;
        iremote[1].rank  = 0;
        iremote[1].index = 0;
    }
    PetscCall(PetscSFSetGraph(sf, nroots, nleaves, ilocal, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER));
    PetscCall(PetscSFSetUp(sf));
    PetscCall(PetscSFView(sf, PETSC_VIEWER_STDOUT_WORLD));
    PetscCall(VecCreate(PETSC_COMM_WORLD, &A));
    PetscCall(VecSetSizes(A, 2, PETSC_DETERMINE));
    PetscCall(VecSetFromOptions(A));
    PetscCall(VecSetUp(A));

    PetscCall(VecDuplicate(A, &B));
    PetscCall(VecDuplicate(A, &Aout));
    PetscCall(VecDuplicate(A, &Bout));
    PetscCall(VecGetArray(A, &bufA));
    PetscCall(VecGetArray(B, &bufB));
    for (i = 0; i < 2; i++) {
        bufA[i] = (PetscScalar)rank;
        bufB[i] = (PetscScalar)(rank) + 10.0;
    }
    PetscCall(VecRestoreArray(A, &bufA));
    PetscCall(VecRestoreArray(B, &bufB));

    PetscCall(VecView(A, PETSC_VIEWER_STDOUT_WORLD));
    PetscCall(VecView(B, PETSC_VIEWER_STDOUT_WORLD));

    PetscCall(VecGetArrayRead(A, (const PetscScalar **)&bufA));
    PetscCall(VecGetArrayRead(B, (const PetscScalar **)&bufB));
    PetscCall(VecGetArray(Aout, &bufAout));
    PetscCall(VecGetArray(Bout, &bufBout));
    PetscCall(PetscSFBcastBegin(sf, MPIU_SCALAR, (const void *)bufA, (void *)bufAout, MPI_REPLACE));
    PetscCall(PetscSFBcastBegin(sf, MPIU_SCALAR, (const void *)bufB, (void *)bufBout, MPI_REPLACE));
    PetscCall(PetscSFBcastEnd(sf, MPIU_SCALAR, (const void *)bufA, (void *)bufAout, MPI_REPLACE));
    PetscCall(PetscSFBcastEnd(sf, MPIU_SCALAR, (const void *)bufB, (void *)bufBout, MPI_REPLACE));
    PetscCall(VecRestoreArrayRead(A, (const PetscScalar **)&bufA));
    PetscCall(VecRestoreArrayRead(B, (const PetscScalar **)&bufB));
    PetscCall(VecRestoreArray(Aout, &bufAout));
    PetscCall(VecRestoreArray(Bout, &bufBout));

    PetscCall(VecView(Aout, PETSC_VIEWER_STDOUT_WORLD));
    PetscCall(VecView(Bout, PETSC_VIEWER_STDOUT_WORLD));
    PetscCall(VecDestroy(&A));
    PetscCall(VecDestroy(&B));
    PetscCall(VecDestroy(&Aout));
    PetscCall(VecDestroy(&Bout));
    PetscCall(PetscSFDestroy(&sf));

    PetscCall(PetscFinalize());
    return 0;
}

/*TEST

   test:
      suffix: basic
      nsize: 2
      filter: grep -v "type" | grep -v "sort"
      args: -sf_type basic

   test:
      suffix: window
      nsize: 2
      filter: grep -v "type" | grep -v "sort"
      output_file: output/ex2_basic.out
      args: -sf_type window -sf_window_sync {{fence active lock}} -sf_window_flavor {{create dynamic allocate}}
      requires: defined(PETSC_HAVE_MPI_ONE_SIDED) defined(PETSC_HAVE_MPI_FEATURE_DYNAMIC_WINDOW)

   # The nightly test suite with MPICH uses ch3:sock, which is broken when winsize == 0 in some of the processes
   test:
      suffix: window_shared
      nsize: 2
      filter: grep -v "type" | grep -v "sort"
      output_file: output/ex2_basic.out
      args: -sf_type window -sf_window_sync {{fence active lock}} -sf_window_flavor shared
      requires: defined(PETSC_HAVE_MPI_PROCESS_SHARED_MEMORY) !defined(PETSC_HAVE_MPICH_NUMVERSION) defined(PETSC_HAVE_MPI_ONE_SIDED)

TEST*/