1.3.1.0 ms.partition

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ms.partition - Function

1.3.1 make a new ms from a subset of an existing ms, without changing any subtables

Description

This function splits out part of the MS into a new MS. Time averaging can be performed in the process. Unlike split, the subtables and IDs (ANTENNA1, DATA_DESCRIPTION_ID, etc.) are never changed to account for the selection.

As a side effect of that property, partition cannot select by channel or correlation, or average channels. It CAN select by spectral window(s).

Arguments


Inputs
outputms	The name of the resulting measurement set
	allowed:	string
	Default:
field	Fields to include, by names or 0-based ids. (” => all)
	allowed:	variant
	Default:
spw	Spectral windows (and :channels) to select
	allowed:	variant
	Default:	*
baseline	Antenna names or indices to select (” => all)
	allowed:	variant
	Default:
timebin	Duration for averaging. Defaults to no averaging.
	allowed:	variant
	Default:	-1s
time	Only use data in the given time range, using the msselection syntax.
	allowed:	string
	Default:
scan	Only use the scan numbers requested using the msselection syntax.
	allowed:	variant
	Default:
uvrange	Limit data by uv distance using the msselection syntax.
	allowed:	variant
	Default:
taql	For the TAQL experts, flexible data selection using the TAQL syntax
	allowed:	string
	Default:
whichcol	’DATA’, ’MODEL_DATA’, ’CORRECTED_DATA’, ’FLOAT_DATA’, ’LAG_DATA’, and/or ’all’
	allowed:	string
	Default:	DATA
tileshape	Tile shape of the disk data columns, most users should not need to touch this parameter [0] => normal tiling, [1] => fast mosaic style tile [4,15,351] => a tile shape of 4 pol 15 chan and 351 rows
	allowed:	variant
	Default:
subarray	Limit data to specific (sub)array numbers.
	allowed:	variant
	Default:
combine	Ignore changes in these columns (scan, and/or state) when time averaging.
	allowed:	string
	Default:
intent	Only use the requested scan intents.
	allowed:	string
	Default:
obs	Only use the requested observation IDs.
	allowed:	string
	Default:

Returns
bool

Example

  ms.open("multiwin.ms")
  ms.partition(’partition.ms’, field=[0], spw=[1], whichcol=’CORRECTED_DATA’)

  In this example we partition out data from the 1st field and 2nd spectral
  window.  Only the CORRECTED_DATA data column will be copied, and it will be
  written to the DATA column of partition.ms.

  ms.open("multiwin.ms")
  ms.partition(’partition.ms’, field=[0], spw=[0,1,2,3],
               whichcol=’CORRECTED_DATA’)

  In this example we partition out calibrated data from the 1st field and four
  spectral windows.

  ms.open("WSRT.ms")
  ms.partition(’partition.ms’, timebin=’20s’, whichcol=’all’, combine=’scan’)
  ms.close()

  This example averages a WSRT MS into 20s bins, selecting whichever of DATA,
  MODEL_DATA, CORRECTED_DATA, or FLOAT_DATA, or LAG_DATA is present.  Normally
  the bins would not cross scans, but in this MS the scan number goes up with
  each integration, making it redundant enough with time that it would defeat
  any time averaging.  Therefore combine parameter forces the SCAN column to be
  ignored for setting the bins.

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