Implementing and UVSUB-like task

CASA Modification Request 21C108, November 2007

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1. Introduction

There is a need to produce a residual data set; a data set with the field model subtracted from the corrected data. This can almost be done in split by writing out the residual data, so this should have low priority

2. Background

3. Requirements

4. Design

Modified VisSetUtil.* to accomodate a new UVSub method to subtract/add model to corrected data column.

Added ms.uvsub(reverse) method to ms tool to utilize new VisSetUtil::UVSub method.

Created uvsub task:

This function subtracts model visibility data from corrected visibility data leaving the residuals in the corrected data column. If the parameter 'reverse' is set true, the process is reversed.

Keyword arguments:

• vis -- Name of input visibility file (MS) default: none; example: vis='ngc5921.ms'
• reverse -- Reverse the operation (add rather than subtract) default: False; example: reverse=true

uvsub(vis='ngc5921.ms', reverse=False)

5. Deployment Checklist

The development branch has the uvsub tool and task for testing and comment from the sponsor.

6. Test Plan

6.1 Internal Testing

6.2 Sponsor Testing

6.3 Integration/Regression Tests

6.4 Testing for Scientific Validity

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Signatures

APPROVED: I acknowledge that my request is fully contained in this MR, and if the CASA development group delivers exactly what I specified, I will be happy.

ACCEPTED: I acknowledge that I have validated the completed code according to the acceptance tests, and I am happy with the results.

Written	- - - - -
Checked	- - - - -
Approved by Scientific Sponsor	- - - - -
Accepted/Delivered by Sponsor	- - - - -

Symbols:

• Use %X% if MR is not complete (will display )
• Use %Y% if MR iscomplete (will display )

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Discussion Area

-- NicoleRadziwill - 30 Oct 2007

-- EdFomalont - 06 Nov 2007

-- EdFomalont - 07 Nov 2007