NRAO Home > CASA > CASA Toolkit Reference Manual
calibrater.initweights - Function

2.1.1 Initialize MS weight info in various ways.


Description

This function initializes the MS weight info in various ways.

If wtmode=’ones’, SIGMA and WEIGHT will be initialized with 1.0, globally.

If wtmode=’nyq’ (the default), SIGMA and WEIGHT will be initialized according to bandwidth and integration time. This is the theoretically correct mode for raw normalized visibilities.

If wtmode=’sigma’, WEIGHT will be initialized according to the existing SIGMA column.

If mode=’weight’, WEIGHT_SPECTRUM will be initialized according to the existing WEIGHT column; dowtspec=T must be specified in this case.

For the above wtmodes, if dowtspec=T (or if the WEIGHT_SPECTRUM column already exists), the WEIGHT_SPECTRUM column will be initialized (uniformly in channel), in a manner consistent with the WEIGHT column. If the WEIGHT_SPECTRUM column does not exist, dowtsp=T will force its creation.

The follow modes should be used with extreme care: If wtmode=’delwtsp’, the WEIGHT_SPECTRUM column will be deleted (if it exists). If wtmode=’delsigsp’, the SIGMA_SPECTRUM column will be deleted (if it exists). Note that creation of SIGMA_SPECTRUM is not supported via this method.

Note that this method does not support any prior selection. Intialization of the weight information must currently be done globally or not at all. This is to maintain consistency.

Arguments





Inputs

wtmode

Initialization mode

allowed:

string

Default:

nyq

dowtsp

Initialize WEIGHT_SPECTRUM column

allowed:

bool

Default:

false

tsystable

Tsys calibration table to apply on the fly

allowed:

string

Default:

gainfield

Select a subset of calibrators from Tsys caltable

allowed:

string

Default:

interp

Interp type in time[,freq]. default==linear,linear

allowed:

string

Default:

spwmap

Spectral windows combinations to form for gaintables(s)

allowed:

intArray

Default:

Returns
bool

Example

 
 
cb.open(’ngc5921.ms’)  
cb.initweights()  
cb.close()  
 

__________________________________________________________________


More information about CASA may be found at the CASA web page

Copyright 2016 Associated Universities Inc., Washington, D.C.

This code is available under the terms of the GNU General Public Lincense


Home | Contact Us | Directories | Site Map | Help | Privacy Policy | Search