static char help[] = "Testing MatCreateMPIAIJWithSplitArrays().\n\n";

#include <petscmat.h>

int main(int argc, char **argv)
{
  Mat             A, B;
  PetscInt        i, j, column, *ooj;
  PetscInt       *di, *dj, *oi, *oj, nd;
  const PetscInt *garray;
  PetscScalar    *oa, *da;
  PetscScalar     value;
  PetscRandom     rctx;
  PetscBool       equal, done;
  Mat             AA, AB;
  PetscMPIInt     size, rank;

  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &argv, NULL, help));
  PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
  PetscCheck(size > 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Must run with 2 or more processes");
  PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));

  /* Create a mpiaij matrix for checking */
  PetscCall(MatCreateAIJ(PETSC_COMM_WORLD, 5, 5, PETSC_DECIDE, PETSC_DECIDE, 0, NULL, 0, NULL, &A));
  PetscCall(MatSetOption(A, MAT_NEW_NONZERO_LOCATION_ERR, PETSC_FALSE));
  PetscCall(MatSetUp(A));
  PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &rctx));
  PetscCall(PetscRandomSetFromOptions(rctx));

  for (i = 5 * rank; i < 5 * rank + 5; i++) {
    for (j = 0; j < 5 * size; j++) {
      PetscCall(PetscRandomGetValue(rctx, &value));
      column = (PetscInt)(5 * size * PetscRealPart(value));
      PetscCall(PetscRandomGetValue(rctx, &value));
      PetscCall(MatSetValues(A, 1, &i, 1, &column, &value, INSERT_VALUES));
    }
  }
  PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
  PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));

  PetscCall(MatMPIAIJGetSeqAIJ(A, &AA, &AB, &garray));
  PetscCall(MatGetRowIJ(AA, 0, PETSC_FALSE, PETSC_FALSE, &nd, (const PetscInt **)&di, (const PetscInt **)&dj, &done));
  PetscCall(MatSeqAIJGetArray(AA, &da));
  PetscCall(MatGetRowIJ(AB, 0, PETSC_FALSE, PETSC_FALSE, &nd, (const PetscInt **)&oi, (const PetscInt **)&oj, &done));
  PetscCall(MatSeqAIJGetArray(AB, &oa));

  PetscCall(PetscMalloc1(oi[5], &ooj));
  PetscCall(PetscArraycpy(ooj, oj, oi[5]));
  /* modify the column entries in the non-diagonal portion back to global numbering */
  for (i = 0; i < oi[5]; i++) ooj[i] = garray[ooj[i]];

  PetscCall(MatCreateMPIAIJWithSplitArrays(PETSC_COMM_WORLD, 5, 5, PETSC_DETERMINE, PETSC_DETERMINE, di, dj, da, oi, ooj, oa, &B));
  PetscCall(MatSetUp(B));
  PetscCall(MatEqual(A, B, &equal));

  PetscCall(MatRestoreRowIJ(AA, 0, PETSC_FALSE, PETSC_FALSE, &nd, (const PetscInt **)&di, (const PetscInt **)&dj, &done));
  PetscCall(MatSeqAIJRestoreArray(AA, &da));
  PetscCall(MatRestoreRowIJ(AB, 0, PETSC_FALSE, PETSC_FALSE, &nd, (const PetscInt **)&oi, (const PetscInt **)&oj, &done));
  PetscCall(MatSeqAIJRestoreArray(AB, &oa));

  PetscCheck(equal, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Likely a bug in MatCreateMPIAIJWithSplitArrays()");

  /* Free spaces */
  PetscCall(PetscFree(ooj));
  PetscCall(PetscRandomDestroy(&rctx));
  PetscCall(MatDestroy(&A));
  PetscCall(MatDestroy(&B));
  PetscCall(PetscFree(oj));
  PetscCall(PetscFinalize());
  return 0;
}

/*TEST

   test:
      nsize: 3
      output_file: output/empty.out

TEST*/
