2.1.1.0 calibrater.setsolve

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calibrater.setsolve - Function

2.1.1 Arrange to solve for calibration

Description

This function specifies the calibration component that will be solved for by the solve function. Currently, only one type can be solved for at one time.

Each calibration component represents a separate calibration matrix correction included in the measurement equation. The different types correspond to different instrumental and atmospheric effects. Currently, the solvable calibration components are types ’G’,’T’,’B’, ’D’ and ’DF’, which are antenna-based, and, ’M’ and ’MF’, which are baseline-based. Arrange to pre-apply any existing calibration components (of types other than the solved-for one) using the setapply function.

The parameters are:

type: Specify the calibration type you want to solve for, from ’G’,’T’,’B’,’D’,’DF’,’M’,’MF’.
t: Specify the solution interval. This can be specified as an integer (units of seconds assumed) or as a string containing a value and units (e.g., ’30s’, ’45min’, ’2h’) or ’inf’ (infinite) or ’int’ (per data integration). A solution interval of 0 (with or without units) is the same as ’int’ (per integration), and negative solution intervals are treated as ’inf’ (infinite).
table: Specify the output calibration table name in which to store the calibration solve result. Existing tables will be deleted and replaced.
append: Append the solutions to an existing table.
preavg: Specify the amount of pre-average (in time) within the solution interval. By default, data are averaged up to the solution interval (or up to 5 minutes for ’D’ solving).
phaseonly: This parameter is deprecated, use apmode.
apmode: Control generation of amplitude-only (’a’), phase-only (’p’), or amplitude-and-phase (’ap’, the default) solutions.
refant: Specify an antenna (using data selection syntax) for referencing the solutions.
solnorm: Normalize the solutions by their mean post-solve. For ’B’, and ’MF’, this is a complex normalization per solution spectrum. For other types, this is a global (per-spw) normalization of the amplitudes only.
minsnr: Specify the SNR below which solution are rejected.
combine: Specify which data axes (spw, field, scan, or some combination) on which the data should be combined to generate a single solution. E.g., combine=’spw’ will force combination of many spws to form a single solution (per solution interval). Similarly, combine=’scan’ with a long solution interval will force the combination of scans to yield individual solutions (per field and spw). Ordinarily, solutions are always broken at scans boundaries. Separate multiple combine options with commas.
fillgaps: For ’B’ solutions, specify the largest solution channel gap (which arise due to flagged data) that will be filled post-solve via interpolation. Such solution gaps remain flagged by default.

Pending improvements:

Change t to solint?
Permit flexible specification of preavg (as for t)

Arguments


Inputs
type	Component type
	allowed:	string
	Default:	G T B D M MF
t	Solution interval (units optional)
	allowed:	any
	Default:	variant
table	Output calibration table name
	allowed:	string
	Default:
append	Append to existing table?
	allowed:	bool
	Default:	false
preavg	Pre-averaging interval (in sec)
	allowed:	double
	Default:	-1.0
phaseonly	Solve only for phase?
	allowed:	bool
	Default:	false
apmode	Solve for ’AP’, ’A’ (amp-only) or ’P’ (phase-only)
	allowed:	string
	Default:	AP
refant	Reference antenna. Default is none.
	allowed:	any
	Default:	variant
minblperant	Minimum number of baselines per ant for solving
	allowed:	int
	Default:	4
solnorm	Normalize solution after solve
	allowed:	bool
	Default:	false
minsnr	SNR threshold for accepting solutions
	allowed:	float
	Default:	0.0
combine	Data axes on which to combine solving (scan, spw, and/or field)
	allowed:	string
	Default:
fillgaps
	allowed:	int
	Default:	0
cfcache	Name of the directory to be used for convolution function disk cache. This is used when type=EP.
	allowed:	string
	Default:
painc	Parallactic Angle increment used to trigger computation of a new convolution function. This is used when type=EP. Default value implies that only one convolution function will be computed for the entire range of observation.
	allowed:	float
	Default:	360.0
fitorder	Order of the polynomial fit, used when type=’A’.
	allowed:	int
	Default:	0
fraction	[SINGLE-DISH SPECIFIC] Edge detection parameter for otfraster/otf calibration. This is a number of edge points as a fraction of total number of points.
	allowed:	float
	Default:	0.1
numedge	[SINGLE-DISH SPECIFIC] Edge detection parameter for otfraster calibration. This is a number of edge points. The value specified here comes before fraction. Note that edge points will be detected from both side of each raster row so that number of edge points is effectively twice of the specified value in each raster row. Default (-1) is to use fraction.
	allowed:	int
	Default:	-1
radius	[SINGLE-DISH SPECIFIC] Specifies radius of the central region of double circle gain calibration for fast scanning data. The value must be either empty or quantum string (numeric value with unit). Default (””) is to use a radius of primary beam.
	allowed:	string
	Default:
smooth	[SINGLE-DISH SPECIFIC] Whether or not applying smoothing during double circle gain calibration for fast scanning data. Default is True.
	allowed:	bool
	Default:	true

Returns
bool

Example

cb.open(’ngc5921.ms’);
cb.setapply (type=’P’);
cb.setsolve (type=’G’,t=’300s’, refant=3, table=’gcal’);
cb.solve();
cb.close();

In this example, analytic (non-solvable) parallactic angle corrections
are pre-applied before G solutions are obtained on a timescale of 300
seconds.  The resulting solutions are phase-referenced to antenna 3,
and stored in a calibration table called ’gcal’.

cb.reset();
cb.setapply (type=’P’,t=5.0);
cb.setapply (type=’G’,table=’gcal’);
cb.setsolve (type=’D’,t=86400.0, preavg=60.0, refant=3, table=’dcal’);
cb.solve();
cb.close();

In this example, the solve/apply state of the calibrater tool is reset
and then the P and G corrections (from above) are applied before
solving for D solutions on a diurnal timescale.  Note that the data
will be averaged only to 60 seconds before the solution.  The resulting
D solutions are stored in a table called ’dcal’.

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