Improve Handling of VLA Sub-Arrays
NRAO Interactive Services Modification Request 3C2n308, June 2008
1. Introduction
The VLA can currently be divided into up to five sub-arrays to observe different fields or frequencies simultaneously. They are mostly independent, but there are some rules about how the correlator allocates resources to each subarray (see below).
2. Background
Currently, the PST does not incorporate sub-arrays in the Session page but we require that a user add the necessary resource information for each sub-array. Therefore, under the current PST the time estimate is overestimated for the total telescope time.
3. Requirements
On the Sessions page there are four column headings: Source Group, Resource, Time, and RMS Noise. Add a column called Subarray that will allow the user to specify to which subarray this Source Group/Resource belongs. The default is that all Source Group/Resources belong to Subarray 1. The tool will have to look for Group/Resources that have the same time request with different subarrays. The time estimate for a session should take the maximum value of the time for all sub-arrays plus the sum of any other Source Group/Resources that are listed. At some future time some validation could be done so that hardware/software rules are enforced (pertaining to correlator resources allocated to each sub-array; once the new WIDAR correlator comes along those rules will change from what they are now). For now, this change should allow total times to be calculated correctly.
For example,
Source Group Resources Time(Hrs) RMS Noise(mJy) Subarray
Group1 Res1 5 0.02 1
Group2 Res1 10 0.1 1
Group2 Res2 10 0.05 2
Group3 Res3 20 0.1 1
Group3 Res2 7 0.3 1
Group4 Res2 7 0.2 2
Group4 Res1 7 0.07 3
Here the total time would be: 5 + 10 + 20 + 7 = 42hrs.
4. Design
Technical lead should provide a brief description of how this will be implemented in the code.
5. Deployment Checklist
Documentation? Systems/hardware/networking things needed for deployment?
6. Test Plan
6.1 Internal Testing
6.3 Integration/Regression Tests
Signatures
APPROVED: I acknowledge that my request is fully contained in this MR, and if the Open Sky (or other NIS or PST developers) deliver 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.
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Discussion Area
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DanaBalser - 19 Feb 2008