message: FESpace::DerefinementMatrix: fixed a case of empty processor.
diff: @@ -1261,7 +1261,7 @@ SparseMatrix* FiniteElementSpace::DerefinementMatrix(int old_ndofs,
  GetLocalDerefinementMatrices(elem_geoms[i], localR[elem_geoms[i]]);
  }
  - SparseMatrix *R = (elem_geoms.Size() > 1)
  + SparseMatrix *R = (elem_geoms.Size() != 1)
  ? new SparseMatrix(ndofs*vdim, old_ndofs*vdim) // variable row size
  : new SparseMatrix(ndofs*vdim, old_ndofs*vdim,
  localR[elem_geoms[0]].SizeI());
  