static char help[] = "Test ISLocalToGlobalMappingCreateSF(), PetscSFSetGraphLayout(), PetscSFGetGraphLayout().\n\n";

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

int main(int argc, char **argv)
{
  MPI_Comm               comm;
  PetscViewer            viewer;
  PetscViewerFormat      format;
  PetscMPIInt            rank, size;
  PetscInt               i, nLocal = 3, nGlobal;
  PetscInt              *indices;
  PetscBool              flg, auto_offset = PETSC_FALSE;
  ISLocalToGlobalMapping l2g0, l2g1;

  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &argv, NULL, help));
  comm = PETSC_COMM_WORLD;
  PetscCallMPI(MPI_Comm_rank(comm, &rank));
  PetscCallMPI(MPI_Comm_size(comm, &size));
  PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &nLocal, NULL));
  PetscCall(PetscOptionsGetBool(NULL, NULL, "-auto_offset", &auto_offset, NULL));
  PetscCall(PetscOptionsCreateViewer(comm, NULL, NULL, "-viewer", &viewer, &format, NULL));
  PetscCall(PetscMalloc1(nLocal, &indices));
  for (i = 0; i < nLocal; i++) indices[i] = i + rank;
  nGlobal = size - 1 + nLocal;
  if (viewer) {
    PetscCall(PetscViewerPushFormat(viewer, format));
    PetscCall(PetscViewerASCIIPrintf(viewer, "nGlobal: %" PetscInt_FMT "\n", nGlobal));
  }

  /* Create a local-to-global mapping using ISLocalToGlobalMappingCreate() */
  {
    PetscCall(ISLocalToGlobalMappingCreate(comm, 1, nLocal, indices, PETSC_USE_POINTER, &l2g0));
    PetscCall(ISLocalToGlobalMappingSetFromOptions(l2g0));
    if (viewer) {
      PetscCall(PetscObjectSetName((PetscObject)l2g0, "l2g0"));
      PetscCall(ISLocalToGlobalMappingView(l2g0, viewer));
    }
  }

  /* Create the same local-to-global mapping using ISLocalToGlobalMappingCreateSF() */
  {
    PetscSF     sf;
    PetscLayout rootLayout;

    PetscCall(PetscSFCreate(comm, &sf));
    PetscCall(PetscLayoutCreateFromSizes(comm, PETSC_DECIDE, nGlobal, 1, &rootLayout));
    PetscCall(PetscSFSetGraphLayout(sf, rootLayout, nLocal, NULL, PETSC_USE_POINTER, indices));
    PetscCall(PetscSFSetFromOptions(sf));
    PetscCall(ISLocalToGlobalMappingCreateSF(sf, auto_offset ? PETSC_DECIDE : rootLayout->rstart, &l2g1));
    if (viewer) {
      PetscCall(PetscObjectSetName((PetscObject)sf, "sf1"));
      PetscCall(PetscObjectSetName((PetscObject)l2g1, "l2g1"));
      PetscCall(PetscSFView(sf, viewer));
      PetscCall(ISLocalToGlobalMappingView(l2g1, viewer));
    }
    /* Test PetscSFSetGraphLayout() / PetscSFGetGraphLayout() */
    {
      PetscLayout lt;
      PetscInt   *ind;
      PetscInt    nl;

      PetscCall(PetscSFGetGraphLayout(sf, &lt, &nl, NULL, &ind));
      PetscCall(PetscLayoutCompare(lt, rootLayout, &flg));
      PetscCheck(flg, comm, PETSC_ERR_PLIB, "PetscSFGetGraphLayout() gives different layout than the one passed to PetscSFSetGraphLayout()");
      for (i = 0; i < nl; i++)
        PetscCheck(ind[i] == indices[i], PETSC_COMM_SELF, PETSC_ERR_PLIB, "PetscSFSetGraphLayout() gives global_roots[%" PetscInt_FMT "] = %" PetscInt_FMT " != %" PetscInt_FMT " = global_roots[%" PetscInt_FMT "] passed to PetscSFSetGraphLayout()", i, ind[i], indices[i], i);
      PetscCall(PetscLayoutDestroy(&lt));
      PetscCall(PetscFree(ind));
    }
    PetscCall(PetscLayoutDestroy(&rootLayout));
    PetscCall(PetscSFDestroy(&sf));
  }

  /* Compare the two local-to-global mappings by comparing results of apply for the same input */
  {
    IS input, output0, output1;

    PetscCall(ISCreateStride(comm, nLocal, 0, 1, &input));
    PetscCall(ISLocalToGlobalMappingApplyIS(l2g0, input, &output0));
    PetscCall(ISLocalToGlobalMappingApplyIS(l2g1, input, &output1));
    if (viewer) {
      PetscCall(PetscObjectSetName((PetscObject)input, "input"));
      PetscCall(PetscObjectSetName((PetscObject)output0, "output0"));
      PetscCall(PetscObjectSetName((PetscObject)output1, "output1"));
      PetscCall(ISView(input, viewer));
      PetscCall(ISView(output0, viewer));
      PetscCall(ISView(output1, viewer));
    }
    PetscCall(ISEqual(output0, output1, &flg));
    PetscCheck(flg, comm, PETSC_ERR_PLIB, "output0 != output1");
    PetscCall(ISDestroy(&input));
    PetscCall(ISDestroy(&output0));
    PetscCall(ISDestroy(&output1));
  }

  if (viewer) {
    PetscCall(PetscViewerPopFormat(viewer));
    PetscCall(PetscViewerDestroy(&viewer));
  }
  PetscCall(ISLocalToGlobalMappingDestroy(&l2g0));
  PetscCall(ISLocalToGlobalMappingDestroy(&l2g1));
  PetscCall(PetscFree(indices));
  PetscCall(PetscFinalize());
  return 0;
}

/*TEST

   test:
      suffix: 1
      nsize: {{1 2 3}separate output}
      args: -auto_offset {{true false}} -viewer

   test:
      suffix: 2
      nsize: {{1 2 3}}
      args: -n 33 -auto_offset {{true false}}
      output_file: output/empty.out

TEST*/
