two separate fixes -- particle_compare and ref_ratio=1 (AMReX-Codes#3655

)

## Summary

## Additional background

## Checklist

The proposed changes:
- [ ] fix a bug or incorrect behavior in AMReX
- [X] add new capabilities to AMReX
- [ ] changes answers in the test suite to more than roundoff level
- [ ] are likely to significantly affect the results of downstream AMReX
users
- [ ] include documentation in the code and/or rst files, if appropriate

Src/AmrCore/AMReX_AmrMesh.cpp

@@ -1082,7 +1082,7 @@ AmrMesh::checkInput ()
  for (int i = 0; i < max_level; i++)
  {
  if (MaxRefRatio(i) < 2) {
- amrex::Error("Amr::checkInput: bad ref_ratios");
+ amrex::Warning("Amr::checkInput: ref_ratios all equal to one!");
  }
  }
 

Tools/Postprocessing/C_Src/particle_compare.cpp

@@ -438,12 +438,15 @@ int main_main()
  std::string fn2;
  std::string pt;
  Real rtol = 0.0;
+ Real atol = 0.0;
 
  int farg=1;
  while (farg <= narg) {
  const std::string fname = amrex::get_command_argument(farg);
  if (fname == "-r" || fname == "--rel_tol") {
  rtol = std::stod(amrex::get_command_argument(++farg));
+ } else if (fname == "--abs_tol") {
+ atol = std::stod(amrex::get_command_argument(++farg));
  } else {
  break;
  }
@@ -472,6 +475,7 @@ int main_main()
  << "\n"
  << " optional arguments:\n"
  << " -r|--rel_tol rtol : relative tolerance (default is 0)\n"
+ << " --abs_tol atol : absolute tolerance (default is 0)\n"
  << std::endl;
  return EXIT_SUCCESS;
  }
@@ -555,16 +559,25 @@ int main_main()
 
  int exit_code = 0;
  for (int i = 0; i < header1.num_comp; ++i) {
- if (global_norms[i+header1.num_comp] > rtol) exit_code = 1;
+ if (global_norms[i ] > atol &&
+ global_norms[i+header1.num_comp] > rtol) exit_code = 1;
  }
 
  if (exit_code == 0)
  {
- amrex::Print() << " PARTICLES AGREE to relative tolerance " << rtol << "\n";
+ if (atol > 0.) {
+ amrex::Print() << " PARTICLES AGREE to relative tolerance " << rtol << " and/or absolute tolerance " << atol << "\n";
+ } else {
+ amrex::Print() << " PARTICLES AGREE to relative tolerance " << rtol << "\n";
+ }
  }
  else
  {
- amrex::Print() << " PARTICLES DISAGREE to relative tolerance " << rtol << "\n";
+ if (atol > 0.) {
+ amrex::Print() << " PARTICLES DISAGREE to relative tolerance " << rtol << " and/or absolute tolerance " << atol << "\n";
+ } else {
+ amrex::Print() << " PARTICLES DISAGREE to relative tolerance " << rtol << "\n";
+ }
  }
 
  return exit_code;