message: Set closest distance to nan where it's not computed.
  This makes it easier to verify the threshold's effects,
  especially if it results in an incomplete computation.
diff: @@ -832,12 +832,12 @@ int main(int argc, char** argv)
  query_mesh_wrapper.getParticleMesh().getNodalVectorField<PointType>(
  "closest_point");
  - if(params.isVerbose())
  - {
  auto cpIndices =
  query_mesh_wrapper.getParticleMesh().getNodalScalarField<axom::IndexType>(
  "cp_index");
  + if(params.isVerbose())
  + {
  auto cpRank =
  query_mesh_wrapper.getParticleMesh().getNodalScalarField<axom::IndexType>(
  "cp_rank");
  @@ -874,11 +874,12 @@ int main(int argc, char** argv)
  }
  mfem::Array<int> dofs;
  + const PointType nowhere(std::numeric_limits<double>::signaling_NaN());
  + const double nodist = std::numeric_limits<double>::signaling_NaN();
  for(auto idx : IndexSet(nQueryPts))
  {
  - const auto& cp = cpPositions[idx];
  - (*distances)(idx) = sqrt(squared_distance(qPts[idx], cp));
  -
  + const auto& cp = cpIndices[idx] >= 0 ? cpPositions[idx] : nowhere;
  + (*distances)(idx) = cpIndices[idx] >= 0 ? sqrt(squared_distance(qPts[idx], cp)) : nodist;
  primal::Vector<double, DIM> dir(qPts[idx], cp);
  directions->FESpace()->GetVertexVDofs(idx, dofs);
  directions->SetSubVector(dofs, dir.data());
  