Issue with loading Varian_TrueBeam6MV_02

[lars-mejnertsen-seetreat]

Trying to load Varian_TrueBeam6MV_02 (and header file) produces TypeError: unknown particle code -3 error. I was able to load Varian_TrueBeam6MV_01 with no issues.

I did change the file extensions to overcome #181.

Steps to Reproduce

1. Download Varian_TrueBeam6MV_02

2. Run the example from Reading IAEA phase space:

   from ParticlePhaseSpace import PhaseSpace, DataLoaders
   from pathlib import Path
   import numpy as np
   
   # get data file:
   file_name = Path("Varian_TrueBeam6MV_02.phsp")
   # read in
   data_schema = np.dtype(
     [
         ("particle type", "i1"),
         ("Ek", "f4"),
         ("x", "f4"),
         ("y", "f4"),
         ("z", "f4"),
         ("Cosine X", "f4"),
         ("Cosine Y", "f4"),
     ]
   )
   
   constants = {"weight": np.float32(1.)}
   
   ps_data = DataLoaders.Load_IAEA(
     data_schema=data_schema,
     constants=constants,
     input_data=file_name,
     n_records=int(1e5),
   )

Error

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[2], line 19
      4 data_schema = np.dtype(
      5     [
      6         (\"particle type\", \"i1\"),
   (...)
     13     ]
     14 )
     17 constants = {\"weight\": np.float32(1.)}
---> 19 ps_data = DataLoaders.Load_IAEA(
     20     data_schema=data_schema,
     21     constants=constants,
     22     input_data=file_name,
     23     n_records=int(1e5),
     24 )

File ~/phase-spaces/.venv/lib/python3.11/site-packages/ParticlePhaseSpace/DataLoaders.py:403, in Load_IAEA.__init__(self, data_schema, constants, input_data, n_records, offset, **kwargs)
    401 self._n_records = n_records
    402 self._offset = offset
--> 403 super().__init__(input_data, **kwargs)

File ~/phase-spaces/.venv/lib/python3.11/site-packages/ParticlePhaseSpace/DataLoaders.py:53, in _DataLoadersBase.__init__(self, input_data, particle_type, units)
     51 self._input_data = input_data
     52 self._check_input_data()
---> 53 self._import_data()
     54 self._check_loaded_data()

File ~/phase-spaces/.venv/lib/python3.11/site-packages/ParticlePhaseSpace/DataLoaders.py:435, in Load_IAEA._import_data(self)
    431             self.data[self._columns[constant]] = pd.Series(self._constants[constant] *
    432                                                            np.ones(self.data.shape[0]), dtype=\"category\")
    434 # OK; add the fields I assume is not in the data
--> 435 particle_types_pdg = self._iaea_types_to_pdg(data['particle type'])
    436 self._check_n_particles_in_header(particle_types_pdg)
    437 self.data[self._columns['particle type']] = particle_types_pdg

File ~/phase-spaces/.venv/lib/python3.11/site-packages/ParticlePhaseSpace/DataLoaders.py:483, in Load_IAEA._iaea_types_to_pdg(self, varian_types)
    481 for type in np.unique(varian_types):
    482     if not type in [1, 2, 3, 4, 5]:
--> 483         raise TypeError(f'unknown particle code {type}')
    484 pdg_types[varian_types==1] = 22  # gammas
    485 pdg_types[varian_types == 2] = 11  # electrons

TypeError: unknown particle code -3