ska_sdp_instrumental_calibration.xarray_processors.apply module

ska_sdp_instrumental_calibration.xarray_processors.apply.apply_gaintable_to_dataset(vis, gaintable, inverse=False)[source]

Apply calibration gains from a GainTable to a Visibility dataset.

This function modifies visibility data by applying antenna-based Jones matrices. It supports both calibration (removing instrumental effects by applying inverse gains) and corruption (simulating instrumental effects by applying forward gains).

The function handles different Jones matrix types:

  • Type 'B' (Bandpass): Gains match the visibility frequency resolution.

  • Type 'T' or 'G': Frequency-independent gains are broadcast across all visibility channels.

Operations are performed per solution interval. The function iterates over time slices defined in the gaintable, applying the corresponding gain solution to the matching block of visibilities using xarray.apply_ufunc() for parallel processing.

Parameters:

  • vis (Visibility) -- The input visibility dataset containing observed data.

  • gaintable (GainTable) -- The calibration solutions (Jones matrices) to apply. Must contain valid soln_interval_slices mapping gain times to visibility times.

  • inverse (bool, optional) -- If True, apply the inverse of the gains (calibrate). If False, apply the gains directly (corrupt/simulate). Default is False.

Returns:

A new Visibility object containing the modified visibility data ('vis' variable updated) with attributes preserved.

Return type:

Visibility

Raises:

AssertionError -- If Jones type is not 'B' and the gaintable has more than one frequency channel.