setdata(mode, nchan, start, step, mstart, mstep, spwid, fieldid, msselect, async)
Description
This setup function selects which data are to be used
subsequently. After invocation of setdata, only the selected subset of data
are operated on.
Data can be selected by field ids, spectral window ids, channels, velocities.
The selection is controlled by the mode argument:
- fieldids
- Selection in field ids.
- spwids
- Selection in spectral window ids.
- channel
- Selection in channels using the nchan, start and step
arguments.
- velocity
- Selection in radio velocity, using the nchan, mstart
and mstep arguments.
Spectral window ids must be specified for the channel and velocity modes.
For channel mode, the other fields have the following meaning:
- nchan
- is the number of output channels. It
defaults to 1, or the number of input channels.
- start
- is the first channel from input dataset that is to be used.
It defaults to 1 (i.e. first channel).
- step
- gives the increment between selected input channels.
The channels are centered on velocities: start, start+step,
start+2*step, etc.
Examples for choosing the parameters for setdata.
af.setdata(mode='fieldids',fieldid=1);
af.setdata(mode='spwids',spwid=1);
af.setdata(mode='spwids & fieldids',spwid=1, fieldid=1);
af.setdata(mode='channel', nchan=64, start=1, step=1, spwid=1)
For velocity modes, the mstart and mstep are the start and step velocities
as strings.
af.setdata(mode='velocity', nchan=64, mstart='20km/s', mstep='-80m/s', spwid=1)
For multi-spectral window selection, the data can be selected as follows
af.setdata(mode='channel', nchan=[20,30], start=[1,1], step=[1,1],
spwid=[1,2])
The above means that you would make a data selection of 20 channels
(starting from 1 steping 1) from the first spectral window and 30
channels (starting from 1 steping 1) from the second spectral window.
- Note:
- Current autoflag setdata implementation does not support cumulative set data. For example, instead of doing
af.setdata(mode='spwids', spwid=1)
af.setdata(mode='fieldids', fieldid=1)
The input should be
af.setdata(mode='spwids & fieldids', spwid=1, fieldid=1)
Arguments
mode |
|
Type of processing: fieldids, spwids, channel or velocity |
|
|
Allowed: |
'fieldids'|'spwids'|'channel'|'velocity' |
nchan |
|
Number of channels to select |
|
|
Allowed: |
Vector of Ints |
|
|
Default: |
1 |
start |
|
Start channels (1-relative) |
|
|
Allowed: |
Vector of Ints |
step |
|
Step in channel number |
|
|
Allowed: |
Vector of Int |
mstart |
|
Start velocity (e.g. '20Km/s') |
|
|
Allowed: |
Quantity |
mstep |
|
Step in velocity (e.g. '100m/s' |
|
|
Allowed: |
Quantity |
spwid |
|
Spectral Window Ids (1 relative) to select |
|
|
Allowed: |
Vector of Ints |
|
|
Default: |
[] |
fieldid |
|
Field Ids (1 relative) to select |
|
|
Allowed: |
Vector of Ints |
|
|
Default: |
[] |
msselect |
|
TQL select string applied as a logical "and" with the other selections |
|
|
Allowed: |
String |
async |
|
Run asynchronously in the background? |
|
|
Allowed: |
Bool |
|
|
Default: |
!dowait |