2.1.1.0 autoflag.setuvbin

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autoflag.setuvbin - Function

2.1.1 Sets up the UV Binner flagging method
Description

The uvbin method works by binning the data on a value vs. UV-distance plane (value is determined by the expr parameter – see the general autoflag module description for a description of this mechanism.) Data in underpopulated bins is then flagged.

The cut-off point for flagging may be expressed in one of two ways:

If the maxpop parameter is specified (e.g. maxpop=4), all bins with less than maxpop points are flagged.
If the thr parameter is specified, a probability cut-off is selected. This is done as follows. The cumulative probability p(N), defined as the probability for a given point to reside in a bin of a population ≤ N, is first computed. All bins of population N, where p(N) <thr, are then flagged.
In simpler terms, using thr=0.01 will flag up to 1% of your data points, beginning with the least populous bins. I.e., first the single-point bins are flagged, then the 2-point bins, and so on, up to the N - 1-point bins, where N is such that flagging the N-point bins would exceed 1% of all data points.
When both maxpop and thr are specified, uvbin will use the higher of the two resulting cut-offs.

Uvbin can be asked to produce a value vs. UV-distance plot, and a plot of p(N). These plots are attached to the flagging report. Uuse of the econoplot mode is recommended when dealing with medium-to-large data sets, for significant reduction in plot file size and printing time.

Arguments


Inputs
thr	Population cut-off, as p(N) value.
	allowed:	double
	Default:	0.0
minpop	Population cut-off, as minimum bin count. Either thr or maxpop must be specified, or both.
	allowed:	int
	Default:	0
nbins	Number of bins (one number for both axes, or separate for UV, value)
	allowed:	intArray
	Default:	50
plotchan	Channel number (0-based) to plot, T for middle channel, or -1 for no plot
	allowed:	int
	Default:	-1
econoplot	Produce an economical plot (crowded bins are not resolved)
	allowed:	bool
	Default:	false
column	Which column to base flagging on
	allowed:	string
	Default:	MODEL CORR DATA
expr	Expression to use
	allowed:	string
	Default:	ABS I
fignore	Ignore existing flags
	allowed:	bool
	Default:	false

Returns
bool

Example

- af:=autoflag(’3C273XC1.MS’)
- af.setdata()
- af.setuvbin(nbins=[50,100],expr="- ABS RR LL",plotchan=40,econoplot=T)

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