static char help[] = "Tests MatTranspose() and MatEqual() for MPIAIJ matrices.\n\n";

#include <petscmat.h>

int main(int argc, char **argv)
{
  Mat         A, B;
  PetscInt    m = 7, n, i, rstart, rend, cols[3];
  PetscScalar v[3];
  PetscBool   equal;
  const char *eq[2];

  PetscFunctionBeginUser;
  PetscCall(PetscInitialize(&argc, &argv, NULL, help));
  PetscCall(PetscOptionsGetInt(NULL, NULL, "-m", &m, NULL));
  n = m;

  /* ------- Assemble matrix, --------- */

  PetscCall(MatCreateAIJ(PETSC_COMM_WORLD, PETSC_DECIDE, PETSC_DECIDE, m, n, 0, 0, 0, 0, &A));
  PetscCall(MatSetOption(A, MAT_NEW_NONZERO_LOCATION_ERR, PETSC_FALSE));
  PetscCall(MatGetOwnershipRange(A, &rstart, &rend));
  if (!rstart) {
    cols[0] = 0;
    cols[1] = 1;
    v[0]    = 2.0;
    v[1]    = -1.0;
    PetscCall(MatSetValues(A, 1, &rstart, 2, cols, v, INSERT_VALUES));
    rstart++;
  }
  if (rend == m) {
    rend--;
    cols[0] = rend - 1;
    cols[1] = rend;
    v[0]    = -1.0;
    v[1]    = 2.0;
    PetscCall(MatSetValues(A, 1, &rend, 2, cols, v, INSERT_VALUES));
  }
  v[0] = -1.0;
  v[1] = 2.0;
  v[2] = -1.0;
  for (i = rstart; i < rend; i++) {
    cols[0] = i - 1;
    cols[1] = i;
    cols[2] = i + 1;
    PetscCall(MatSetValues(A, 1, &i, 3, cols, v, INSERT_VALUES));
  }
  PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
  PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));

  PetscCall(MatTranspose(A, MAT_INITIAL_MATRIX, &B));

  PetscCall(MatEqual(A, B, &equal));

  eq[0] = "not equal";
  eq[1] = "equal";
  PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Matrices are %s\n", eq[equal]));

  PetscCall(MatTranspose(A, MAT_REUSE_MATRIX, &B));
  PetscCall(MatEqual(A, B, &equal));
  if (!equal) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "MatTranspose with MAT_REUSE_MATRIX failed"));

  /* Free data structures */
  PetscCall(MatDestroy(&A));
  PetscCall(MatDestroy(&B));

  PetscCall(PetscFinalize());
  return 0;
}

/*TEST

    test:

    test:
      suffix: 2
      nsize: 2
      output_file: output/ex58_1.out

TEST*/