flint.selfcal.casa

Utilities related to using casa tasks to perform self-calibration.

This tooling is mostly centred on using gaincal from casatasks.

Classes

GainCalOptions

Options provided to the casatasks gaincal function. Most options correspond to those in gaincal.

Functions

_process_gaincal_options(→ GainCalOptions)

Helper to process and update GaincalOptions on initialise of self-calibration routine

_skippable_ms_copy_and_clean(→ bool)

In some circumstances components of self-calibration may be

check_for_valid_calibration_table(→ bool)

Basic checks to ensure that the calibration table

cli(→ None)

copy_and_clean_ms_casagain(→ flint.options.MS)

Create a copy of a measurement set in preparation for selfcalibration

create_spws_in_ms(→ pathlib.Path)

Use the casa task mstransform to create nspw spectral windows

gaincal_applycal_ms(→ flint.options.MS)

Perform self-calibration using casa's gaincal and applycal tasks against

get_parser(→ argparse.ArgumentParser)

merge_spws_in_ms(→ pathlib.Path)

Attempt to merge together all SPWs in the input measurement

Module Contents

class flint.selfcal.casa.GainCalOptions(/, **data: Any)[source]

Bases: flint.options.BaseOptions

Options provided to the casatasks gaincal function. Most options correspond to those in gaincal.

calmode: str = 'p'[source]

Calibration mode.

gaintype: str = 'G'[source]

The gain type that would be solved for.

minsnr: float = 0.0[source]

Minimum signal-to-noise of the solutions. Below this the solutions and data are flagged.

nspw: int = 1[source]

The number of spectral windows to use during the self-calibration routine. This will be used to craft an appropriate select_spw= interval range. If larger than one, gaincal will be carried out against each interval and results will be appended to a common solutions file.

round: int = 0[source]

Self-calibration round. Not a gaincal option.

selectdata: bool = True[source]

Whether data selection actions will be applied in gaincal.

solint: str = '60s'[source]

Solution length interval

solnorm: bool = True[source]

Renormalise the distribution of the amplite gains so the mean is unity.

uvrange: str = '>200m'[source]

Data selected to go through calibration procedure

flint.selfcal.casa._process_gaincal_options(gain_cal_options: GainCalOptions | None = None, update_gain_cal_options: dict[str, Any] | None = None) → GainCalOptions[source]

Helper to process and update GaincalOptions on initialise of self-calibration routine

Parameters:

  • gain_cal_options (GainCalOptions | None, optional) – Any existing gaincal options. Defaults to None.

  • update_gain_cal_options (dict[str, Any] | None, optional) – Overrides to provide the to input gaincal options or defaults. Defaults to None.

Returns:

options to use throughout gaincalibtaion

Return type:

GainCalOptions

flint.selfcal.casa._skippable_ms_copy_and_clean(ms: flint.options.MS, out_ms_path: pathlib.Path, rename_ms: bool = False) → bool[source]

In some circumstances components of self-calibration may be partway through before being restarted. This is to try to allow continuing from that point if changes are known and operation modes support. Critically:

  • the input ms must not exist

  • the output ms must exist

  • renaming of the ms is active (as opposed to copying)

  • DATA column exists

Parameters:

  • ms (MS) – The target MS that was going to be self-calibrated

  • out_ms_path (Path) – The expected MS output name

  • rename_ms (bool, optional) – Whether the MS will simply be renamed. Defaults to False.

Raises:

ValueError – Raised when neither the input or output MS vsn not be found.

Returns:

Indicates where previous self-calibration round has partly been attempted, and if it can be continued.

Return type:

bool

flint.selfcal.casa.check_for_valid_calibration_table(caltable_path: pathlib.Path) → bool[source]

Basic checks to ensure that the calibration table from CASAs gaincal is valid

Parameters:

caltable_path (Path) – Table path to examine

Returns:

Whether the input table appears to be a CASA solutions table from gaincal

Return type:

bool

flint.selfcal.casa.cli() → None[source]
flint.selfcal.casa.copy_and_clean_ms_casagain(ms: flint.options.MS, round: int = 1, verify: bool = True, rename_ms: bool = False) → flint.options.MS[source]

Create a copy of a measurement set in preparation for selfcalibration using casa’s gaincal and applycal. Applycal only works when calibrating DATA and creating a CORRECTED_DATA column. Columns are removed in the copied MS to allow this.

If the MS is large the move_ms option will simply renamed the input MS, adjusting the columns appropriately. Note that this potentially involves deleting the DATA column if present and renaming CORRECTED_DATA.

Parameters:

  • ms (MS) – Measurement set that would go through self-calibration.

  • round (int, optional) – The self-calibration round. Defaults to 1.

  • verify (bool, optional) – Verify that copying the measurementt set (done in preparation for gaincal) was successful. Uses a call to rsync. Defaults to True.

  • move_ms (bool, optional) – Rather than copying the MS, simple renamed the MS and modify columns appropriately. Defaults to False.

Returns:

Copy of input measurement set with columns removed as required.

Return type:

MS

flint.selfcal.casa.create_spws_in_ms(casa_container: pathlib.Path, ms_path: pathlib.Path, nspw: int) → pathlib.Path[source]

Use the casa task mstransform to create nspw spectral windows in the input measurement set. This is necessary when attempting to use gaincal to solve for some frequency-dependent solution.

Parameters:

  • casa_container (Path) – Path to the singularity container with CASA tooling

  • ms_path (Path) – The measurement set that should be reformed to have nspw spectral windows

  • nspw (int) – The number of spectral windows to create

Returns:

The path to the measurement set that was updated

Return type:

Path

flint.selfcal.casa.gaincal_applycal_ms(ms: flint.options.MS, casa_container: pathlib.Path, round: int = 1, gain_cal_options: GainCalOptions | None = None, update_gain_cal_options: dict[str, Any] | None = None, archive_input_ms: bool = False, skip_selfcal: bool = False, rename_ms: bool = False, archive_cal_table: bool = False) → flint.options.MS[source]

Perform self-calibration using casa’s gaincal and applycal tasks against an input measurement set.

Parameters:

  • ms (MS) – Measurement set that will be self-calibrated.

  • round (int, optional) – Round of self-calibration, which is used for unique names. Defaults to 1.

  • casa_container (Path) – A path to a singularity container with CASA tooling.

  • gain_cal_options (Optional[GainCalOptions], optional) – Options provided to gaincal. Defaults to None.

  • update_gain_cal_options (Optional[Dict[str, Any]], optional) – Update the gain_cal_options with these. Defaults to None.

  • archive_input_ms (bool, optional) – If True, the input measurement set will be compressed into a single file. Defaults to False.

  • skip_selfcal (bool, optional) – Should this self-cal be skipped. If True, the a new MS is created but not calibrated the appropriate new name and returned.

  • rename_ms (bool, optional) – It True simply rename a MS and adjust columns appropriately (potentially deleting them) instead of copying the complete MS. If True archive_input_ms is ignored. Defaults to False.

  • archive_cal_table (bool, optional) – Archive the output calibration table in a tarball. Defaults to False.

Raises:

GainCallError – Raised when no self-calibration solutions were found

Returns:

The self-calibrated measurement set.

Return type:

MS

flint.selfcal.casa.get_parser() → argparse.ArgumentParser[source]
flint.selfcal.casa.merge_spws_in_ms(casa_container: pathlib.Path, ms_path: pathlib.Path) → pathlib.Path[source]

Attempt to merge together all SPWs in the input measurement set using the cvel casa task. This can be a little fragile.

The cvel task creates a new measurement set, so there would temporially be a secondary measurement set.

Parameters:

ms_path (Path) – The measurement set that should have its SPWs merged together.

Returns:

The measurement set with merged SPWs. It will have the same path as ms_path, but is a new measurement set.

Return type:

Path