2.2.1.0 calibrater.setdata

calibrater.setdata - Function

2.2.1 Set the data selection for subsequent processing
Description

This function selects which data will be treated by subsequent execution of the solve and correct functions. Note that data selection is not cumulative; any selection made in a previous call is replaced by the selection from the current call.

The arguments are used as follows:

mode: indicates how you select the desired channels. A value of ’none’ means select all data (make no channel selection); all channel- or velocity-dependent arguments are ignored in this case. A value of ’channel’ indicates that you select by channel number. A value of ’velocity’ indicates that you select by radio velocity and a value ’opticalvelocity’ indicates that you select by optical velocity.
nchan: is the number of selected channels for mode=’channel’. It defaults to 1; to select all channels, set to 0.
start: is active only when mode=’channel’ and specifies the first channel to be selected. It defaults to 1.
step: is active only when mode=’channel’ and specifies the increment between selected input channels. It defaults to 1.
The channels are centered on velocities: start, start+step, start+2*step, etc.
mstart: is active only when mode=’velocity’ or mode=’optical velocity’. It specifies the start velocity to select as a quantity string. The default is 0.
mstep: is active only when mode=’velocity’ or mode=’optical velocity’. It specifies the increment between selected channels as a quantity string. The default is 0 which is not very useful...
The channels are centered on velocities: mstart, mstart+mstep, mstart+2*mstep, etc.
msselect: is used to specify a subselection of data according to field, spectral window, time, etc., and should be specified as a valid TaQL expression.

Arguments


Inputs
mode		Type of data selection: channel or velocity
		allowed:	string
		Default:	channel velocity none
nchan		Number of channels to select (mode=’channel’)
		allowed:	int
		Default:	1
start		Start channel (0-relative) (mode=’channel’)
		allowed:	int
		Default:	0
step		Step in channel number (mode=’channel’)
		allowed:	int
		Default:	1
mstart	km/s	Start velocity (e.g. ’20Km/s’)
		allowed:	doublekm/s
		Default:	0.0
mstep	km/s	Step in velocity (e.g. ’100m/s’)
		allowed:	doublekm/s
		Default:	0.0
uvrange		UV range (in klambda) (e.g. [0, 50]). Defaults to no restriction.
		allowed:	doubleArray
		Default:	0
msselect		TAQL selection string. Default is no selection.
		allowed:	string
		Default:

Returns
bool

Example

c:=calibrater(’3C273XC1.MS’);

Select according to channel:

c.setdata(mode=’channel’,nchan=512,start=1,step=1,msselect=’FIELD_ID==1’)

Select according to velocity:

c.setdata(mode=’velocity’, nchan=64, mstart=’20km/s’, mstep=’-100m/s’);

Reset selection to the entire dataset

c.setdata()

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