National Radio
Astronomy Observatory

Introspective Member Functions

The introspective member functions provide information about the shape and contents of the file. For example, the numchannel() member function returns the number of channels corresponding to each spectral window. Also, the field() member function returns the field names or numbers. With this information, users can easily select and keep track of limited regions of the calibration table, even from the command line, by minimizing the number of iterations.

The member function definitions are:

ca.antenna( name=True ) - This member function returns the antenna numbers or names as a python list of strings.

ca.calname() - This member function returns the new format calibration table name as a python string.

ca.feed() - This member function returns the feed names as a python list of strings (’X’, ’Y’ for linear; ’R’, ’L’ for circular; ’S’ for ”scalar”, when the calibration solutions are performed simultaneously for both polarizations). If the basis is unknown, then the basis functions are ’1’ and ’2’. This kludge was added to handle incomplete calibration tables.

ca.field( name=True ) - This member function returns the field numbers or names as a python list of strings.

ca.freq() - This member function returns the frequencies in the table as a python dictionary (the keys are the spectral window numbers and the elements are numpy float arrays containing the frequencies).

ca.msname() - This member function returns the parent measurement set name as a python string.

ca.numantenna() - This member function returns the number of antennas as a python integer.

ca.numchannel() - This member function returns the number of channels for each spectral window as a list of python integers.

ca.numfeed() - This member function returns the number of feeds as a python integer.

ca.numfield() - This member function returns the number of fields as a python integer.

ca.numspw() - This member function returns the number of spectral windows as a python integer.

ca.numtime() - This member function returns the number of times as a python integer.

ca.partype() - This member function returns the parameter column type (’Float’ or ’Complex’).

ca.polbasis() - This member function returns the polarization basis (’L’ for linear or ’C’ for circular). If the basis is unknown, ’U’ is returned. This kludge was added to handle incomplete calibration tables.

ca.spw( name=True ) - This member function returns the spectral window numbers or names as a python list of strings.

ca.time() - This member function returns the times as a python list of floats (in units of MJD seconds). In the future, date strings will be available.

ca.viscal() - This member function returns the type of new formation calibration table as a python string. For example ’B’ is a bandpass table, ’G’ is a gain table, etc.

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