Cactus ParameterGetXXX functions return values for non-active thorns

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Issue #1343 new
Roland Haas created an issue

using eg. CCTK_ParameterValString it is possible to access parameters of non-active thorns, eg. the line in CarpetIOHDF5/src/ lines 280ff

  char *buffer = CCTK_ParameterValString ("refinement_levels",
  assert (buffer);
  CCTK_VInfo (CCTK_THORNSTRING, "Using %i reflevels from checkpoint file. "
              "Ignoring value '%s' in parameter file.",
              num_reflevels, buffer);
  free (buffer);

char buffer[32];
snprintf (buffer, sizeof (buffer), "%d", num_reflevels);
int const retval = CCTK_ParameterSet ("refinement_levels", "CarpetRegrid",

will actually get a value (the default value it seems) and is able to steer a value of a non-active thorns.

Reading the Cactus docs this behaviour is not forbidden however I personally find it a bit confusing.


Comments (2)

  1. Frank Löffler
    • removed comment

    Do you suggest to let CCTK_ParameterValString return an error in case a thorn isn't active? I don't see a good reason against it, apart from, maybe:

    Going wild: what if we want to be able to activate/deactivate thorns at runtime at some point? We then probably want the ability to steer their parameters before they get activated. Of course, that's not a good argument at the moment ...

  2. Roland Haas reporter
    • removed comment

    Yes, I would propose that trying to set/query parameters that belong (only) to deactivated thorns should result in an error. To my thinking non-active thorns are not present at all and should be treated as if they were not compiled in in the first place (which is currently not the case).

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