calibrater.setdata

Set the data selection for subsequent processing

Synopsis setdata(mode, nchan, start, step, mstart, mstep, uvrange, msselect)

Arguments

`mode`	`in`	Type of data selection: channel or velocity
		`Allowed:`	`String from 'none'\|'channel'\|'velocity'`
		`Default:`	`'none'`
`nchan`	`in`	Number of channels to select (mode='channel')
		`Allowed:`	`Int`
		`Default:`	`1`
`start`	`in`	Start channel (1-relative) (mode='channel'
		`Allowed:`	`Int`
		`Default:`	`1`
`step`	`in`	Step in channel number (mode='channel')
		`Allowed:`	`Int`
		`Default:`	`1`
`mstart`	`in`	Start velocity (e.g. '20Km/s')
		`Allowed:`	`Quantity`
		`Default:`	`'0km/s'`
`mstep`	`in`	Step in velocity (e.g. '100m/s'
		`Allowed:`	`Quantity`
		`Default:`	`'0km/s'`
`uvrange`	`in`	UV range (in klambda) (e.g. [0, 50]). Default is no restriction.
		`Allowed:`	`Vector of Doubles`
		`Default:`	`0`
`msselect`	`in`	TAQL selection string. Default is no selection.
		`Allowed:`	`String`
		`Default:`	`' '`

Returns Bool

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.

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()

Next: calibrater.setapply - Function Up: calibrater - Tool Previous: calibrater - Constructor Contents Index

	`Package`	`synthesis`
	`Module`	`calibrater`
	`Tool`	`calibrater`

calibrater.setdata - Function