def create_event(self):
"""
Generate a neutrino event in the ice volume.
Creates a neutrino with a random vertex in the volume, a random
direction, and an energy based on ``get_energy``. Particle type is
randomly chosen, and its interaction type is also randomly chosen based
on the branching ratio. Weights the particles according to their
survival probability through the Earth and their probability of
interacting in the ice at their vertex. If Earth shadowing has been
turned on then particles which don't survive transit through the Earth
are skipped, and surviving particles are given a survival weight of 1.
Currently each `Event` returned consists of only a single `Particle`.
Returns
-------
Event
Random neutrino event not shadowed by the Earth.
See Also
--------
pyrex.Event : Class for storing a tree of `Particle` objects
representing an event.
pyrex.Particle : Class for storing particle attributes.
"""
self.count += 1
vtx = self.get_vertex()
u = self.get_direction()
E = self.get_energy()
particle_id = self.get_particle_type()
particle = Particle(particle_id=particle_id,
vertex=vtx,
direction=u,
energy=E,
interaction_model=self.interaction_model)
weights = self.get_weights(particle)
if not self.shadow:
particle.survival_weight = weights[0]
particle.interaction_weight = weights[1]
logger.debug(
"Successfully created %s with survival weight %d and " +
"interaction weight %d", particle, weights[0], weights[1])
return Event(particle)
elif np.random.rand() < weights[0]:
particle.survival_weight = 1
particle.interaction_weight = weights[1]
logger.debug(
"Successfully created %s with survival weight %d and " +
"interaction weight %d", particle, weights[0], weights[1])
return Event(particle)
else:
# Particle was shadowed by the earth. Try again
logger.debug("Particle creation shadowed by the Earth")
return self.create_event()
def _load_events(self):
"""
Pulls the next chunk of events into memory.
Reads events up to the ``slice_range`` into memory from the current
file. If the current file is exhausted, loads the next file.
Returns
-------
list
List of `Event` objects read from the current file.
Raises
------
StopIteration
If the end of the last file in the file list has been reached.
"""
if self._file_index < 0 or self._event_index >= len(self._file):
self._next_file()
start = self._event_index
stop = self._event_index + self.slice_range
self._event_index += self.slice_range
if stop > len(self._file):
stop = len(self._file)
self._events = []
self._event_counts = []
for file_event in self._file[start:stop]:
info = file_event.get_particle_info()
particles = []
for p in info:
part = Particle(particle_id=p['particle_id'],
vertex=(p['vertex_x'], p['vertex_y'],
p['vertex_z']),
direction=(p['direction_x'], p['direction_y'],
p['direction_z']),
energy=p['energy'],
interaction_model=self.interaction_model,
interaction_type=p['interaction_kind'])
part.interaction.inelasticity = p['interaction_inelasticity']
part.interaction.em_frac = p['interaction_em_frac']
part.interaction.had_frac = p['interaction_had_frac']
part.survival_weight = p['survival_weight']
part.interaction_weight = p['interaction_weight']
particles.append(part)
self._events.append(Event(particles))
self._event_counts.append(file_event.total_events_thrown)