message: use scalar group comm, works in nonconforming case
diff: @@ -362,9 +362,11 @@ void ParGridFunction::ProjectDiscCoefficient(Coefficient &coeff, AvgType type)
  AccumulateAndCountZones(coeff, type, zones_per_vdof);
  // Count the zones globally.
  - GroupCommunicator &gcomm = pfes->GroupComm();
  - gcomm.Reduce<int>(zones_per_vdof, GroupCommunicator::Sum);
  - gcomm.Bcast(zones_per_vdof);
  + GroupCommunicator* gcomm = pfes->ScalarGroupComm();
  + gcomm->Reduce<int>(zones_per_vdof, GroupCommunicator::Sum);
  + gcomm->Bcast(zones_per_vdof);
  + delete gcomm;
  +
  // Accumulate for all tdofs.
  HypreParVector *tv = this->ParallelAssemble();
  this->Distribute(tv);
  