pipeline.hifa.cli.hifa_gfluxscaleflag

pipeline.hifa.cli.hifa_gfluxscaleflag = <pipeline.hifa.cli.hifa_gfluxscaleflag._hifa_gfluxscaleflag object>

hifa_gfluxscaleflag —- Derive the flux density scale with flagging

This task computes the flagging heuristics on the phase calibrator and flux calibrator by calling hif_correctedampflag which looks for outlier visibility points by statistically examining the scalar difference of corrected amplitudes minus model amplitudes, and flags those outliers. The philosophy is that only outlier data points that have remained outliers after calibration will be flagged. The heuristic works equally well on resolved calibrators and point sources because it is not performing a vector difference, and thus is not sensitive to nulls in the flux density vs. uvdistance domain. Note that the phase of the data is not assessed.

In further detail, the workflow is as follows: a snapshot of the flagging state is preserved at the start, a preliminary phase and amplitude gaincal solution is solved and applied, the flagging heuristics are run and any outliers are marked for flagging, the flagging state is restored from the snapshot. If any outliers were found, then these are flagged. Plots are generated at two points in this workflow: after preliminary phase and amplitude calibration but before flagging heuristics are run, and after flagging heuristics have been run and applied. If no points were flagged, the ‘after’ plots are not generated or displayed. The score for this stage is the standard data flagging score, which depends on the fraction of data flagged.

Output

results – If pipeline mode is ‘getinputs’ then None is returned. Otherwise the results object for the pipeline task is returned.

——— parameter descriptions ———————————————

vis The list of input MeasurementSets. Defaults to the list of

MeasurementSets specified in the pipeline context.

example: vis=[‘M51.ms’]

intent A string containing a comma delimited list of intents against

which the selected fields are matched. If undefined (default), it will select all data with the AMPLITUDE, PHASE, and CHECK intents, except for one case: if one of the AMPLITUDE intent fields was also used for BANDPASS, then this task will select only data with PHASE and CHECK intents.

example: intent=’PHASE’

phaseupsolint The phase correction solution interval in CASA syntax.

example: phaseupsolint=’300s’

solint Time and channel solution intervals in CASA syntax.

example: solint=’inf,10ch’, solint=’inf’

minsnr Solutions below this SNR are rejected. refant Reference antenna names. Defaults to the value(s) stored in the

pipeline context. If undefined in the pipeline context defaults to the CASA reference antenna naming scheme.

example: refant=’DV01’, refant=’DV06,DV07’

antnegsig Lower sigma threshold for identifying outliers as a result of bad

antennas within individual timestamps.

antpossig Upper sigma threshold for identifying outliers as a result of bad

antennas within individual timestamps.

tmantint Threshold for maximum fraction of timestamps that are allowed to

contain outliers.

tmint eshold for maximum fraction of “outlier timestamps” over

“total timestamps” that a baseline may be a part of.

tmbl Initial threshold for maximum fraction of “bad baselines” over “all

baselines” that an antenna may be a part of.

antblnegsig Lower sigma threshold for identifying outliers as a result of

“bad baselines” and/or “bad antennas” within baselines, across all timestamps.

antblpossig threshold for identifying outliers as a result of

“bad baselines” and/or “bad antennas” within baselines, across all timestamps.

relaxed_factor Relaxed value to set the threshold scaling factor to under

certain conditions (see task description).

niter Maximum number of times to iterate on evaluation of flagging

heuristics. If an iteration results in no new flags, then subsequent iterations are skipped.

pipelinemode e operating mode. In ‘automatic’ mode the pipeline

determines the values of all context defined pipeline inputs automatically. In interactive mode the user can set the pipeline context defined parameters manually. In ‘getinputs’ mode the user can check the settings of all pipeline parameters without running the task.

default: ‘automatic’.

dryrun Run the commands (True) or generate the commands to be run but

do not execute (False).

acceptresults Add the results of the task to the pipeline context (True) or

reject them (False).

——— examples ———————————————————–

1. run with recommended settings to create flux scale calibration with flagging using recommended thresholds:

hifa_gfluxscaleflag()