National Radio
Astronomy Observatory

ms.ms - Function

1.3.1 Create an ms tool attached to a measurement set


Description

This is the most commonly used constructor. It creates an ms tool which is attached to the specified measurement set table.

By default the table is opened read only to prevent you from accidently making changes to the measurement set. Set nomodify to False you you do intend to make changes.

Setting the lock argument to True will permanently lock the table preventing other processes from writing to the measurement set. Unless you expect this to happen, and want to prevent it, you should leave the lock argument at the default value which implies auto-locking.

The host argument specifies which machine the precompiled ms process should be started on. The default value starts it on the same machine as the one that casapy is running on.

In order to run the ms tool on a remote machine you need to satisfy all the following conditions.

• It must be possible to start casa on the remote machine
• You must be able to log onto the remote machine without having to type a password
• The CASAPATH environment variable must be defined on the remote machine. You may want to set this up in the relevant “dot” file eg., adding a line like source~/usr/local/aips++/aipsinit.csh in your .cshrc file (for csh).

One quick way to check if all three conditions are met is to type, on your local machine (rsh host ’echo

$CASAPATH’) where host is replaced by the name of the remote machine. If the value of the CASAPATH variable that is printed does not contain something like aips-root~architecture~site~host and that all the values are correct for the remote machine you can be certain that starting the ms tool, or any casa server, on the remote host will not work

Each ms tool can only run one function at a time. To solve this you start two servers. The forcenewserver argument allows you to do this by overriding the default behaviour of having each ms tool share the same server.

This function returns an ms tool or fail if something went wrong, like an error in the measurement set name.

Arguments

Example

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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