DL2EventLoader

class ctapipe.io.DL2EventLoader(**kwargs: Any)

Bases: Component

Component for loading events and simulation metadata, applying preselection and optional derived column logic.

Attributes Summary

classes
event_reader_function	Function of TableLoader used to read event chunks.
event_reader_kwargs	Extra keyword arguments passed to the event reading function, e.g., {'path': '/dl2/event/telescope/Reconstructor'}

Methods Summary

get_simulation_information(loader, obs_time)	Extract simulation information from the input file.
load_preselected_events(chunk_size, obs_time)	Load and filter events from the file.
make_derived_columns(events)	Add derived quantities (e.g., theta, FOV offsets) to the table.
make_event_weights(events, spectrum, kind[, ...])	Compute event weights to match the target spectrum.

Attributes Documentation

classes = [<class 'ctapipe.io.dl2_tables_preprocessing.DL2EventPreprocessor'>]

event_reader_function

Function of TableLoader used to read event chunks. E.g., ‘read_subarray_events_chunked’ or ‘read_telescope_events_chunked’.

event_reader_kwargs

Extra keyword arguments passed to the event reading function, e.g., {‘path’: ‘/dl2/event/telescope/Reconstructor’}

Methods Documentation

get_simulation_information(loader: TableLoader, obs_time: Quantity) → tuple[SimulatedEventsInfo, PowerLaw]

Extract simulation information from the input file.

Parameters:

loaderTableLoader

Loader object for reading from the input file.

obs_timeQuantity

Total observation time.

Returns:

sim_infoSimulatedEventsInfo

Metadata about the simulated events.

spectrumPowerLaw

Power-law model derived from simulation configuration.

Raises:

NotImplementedError

If simulation parameters vary across runs.

load_preselected_events(chunk_size: int, obs_time: Quantity) → tuple[QTable, int, dict]

Load and filter events from the file.

Parameters:

chunk_sizeint

Size of chunks to read from the file.

obs_timeQuantity

Observation time to scale weights.

Returns:

tableQTable

Filtered and processed event table.

n_raw_eventsint

Number of events before selection.

metadict

Metadata dictionary with simulation info and input spectrum.

make_derived_columns(events: QTable) → QTable

Add derived quantities (e.g., theta, FOV offsets) to the table.

Parameters:

eventsQTable

Table containing normalized events.

Returns:

QTable

Table with added derived columns.

make_event_weights(events: QTable, spectrum: PowerLaw, kind: str, fov_offset_bins: Quantity | None = None) → QTable

Compute event weights to match the target spectrum.

Parameters:

eventsQTable

Input events.

spectrumPowerLaw

Spectrum from simulation.

kindstr

Type of events (“gammas”, etc.).

fov_offset_binsQuantity, optional

Offset bins for integrating the diffuse flux into point source bins.

Returns:

QTable

Table with updated weights.

Raises:

ValueError

If fov_offset_bins is required but not provided.