Merge pull request #21 from ChristopherMayes/add_particlestatus_enum

Add particlestatus enum

pmd_beamphysics/__init__.py

@@ -1,4 +1,5 @@
-from .particles import ParticleGroup, single_particle
+from .particles import ParticleGroup,  single_particle
+from .status import ParticleStatus
 from .fields.fieldmesh import FieldMesh
 from .readers import particle_paths
 from .writers import pmd_init

pmd_beamphysics/interfaces/astra.py

@@ -1,4 +1,5 @@
 import numpy as np
+from pmd_beamphysics.status import ParticleStatus
 from pmd_beamphysics.readers import component_alias
 import os
 
@@ -173,9 +174,12 @@ def vprint(*a, **k):
     # Revese: 1->5, 2->1
     status = particle_group.status
     astra_status = status.copy()
-    astra_status[ np.where(status==1) ] = 5
-    astra_status[ np.where(status==2) ] = 1
+    astra_status[ np.where(status==1) ] = 5 # Astra normal (alive)
+    astra_status[ np.where(status==2) ] = 1 # Astra passive
+    astra_status[ np.where(status==ParticleStatus.CATHODE)] = -1 # Astra cathode
+
     data['status'][i_start:] = astra_status
+
     # Handle reference particle. If any -1 are found, assume we are starting at the cathode
     if -1 in astra_status:
         ref_particle['status']= -1 # At cathode

pmd_beamphysics/status.py

@@ -0,0 +1,9 @@
+from enum import IntEnum
+
+class ParticleStatus(IntEnum):
+    """
+    Particle Status Enum
+    This is defined by the openPMD-beamphysics standard as integers.
+    """
+    CATHODE =  0 
+    ALIVE   =  1