[daip] SPCAL question and problem
egreisen at nrao.edu
Tue Jun 23 13:39:04 EDT 2009
Hanno Spreeuw wrote:
> I have a question about SPCAL and a small problem. How are the frequency
> dependent D-terms computed? Are the solutions expressed as coefficients
> of a polynomial?
> LPCAL seems to export more numbers to the AN table than SPCAL does.
> The problem:
> If I run SPCAL it crashes:
> "castor> SPCAL4: Interferometer Element 13
> castor> SPCAL4: R: Amp = 0.00403+/- 0.00050 Phase(deg) = -89.35+/-
> castor> SPCAL4: L: Amp = 0.00855+/- 0.00059 Phase(deg) = 95.15+/-
> castor> SPCAL4: Interferometer Element 14
> castor> SPCAL4: R: Amp = 0.00004+/- 0.00000 Phase(deg) = 127.40+/-
> castor> SPCAL4: L: Amp = 0.00776+/- 0.00059 Phase(deg) = 145.01+/-
> castor> SPCAL4: True RMS residual = 5.16499338D-01
> castor> SPCAL4: Pre-fit RMS = 9.43064733D-01
> castor> SPCAL4: TABCOP ERROR 1 UPDATING AN TABLE
> castor> SPCAL4: Purports to die of UNNATURAL causes"
> I "solved" this by adding an extra identical AN table to the dataset.
> One is deleted, but the remaining one is updated by SPCAL.
> Perhaps this issue has to do with the fact that this is WSRT data.
SPCAL makes a mess of which AN file to do. It is supposed to take the
one for SUBARRAY and make a copy to a new temporary file one larger than
the max, add 2 parameters (ellipticity and orientation) per antenna and
polarization at BIF only, then delete AN file SUBARRAY, copy max+1 to
SUBARRAY and then delete the max +1. Since it did not add the 1 it took
max for the scratch one, copied SUBARRAY to it etc. Making a spare one
as you did "fixes" the bug. A better fix will arrive with tomorrow's MNJ.
LPCAL does all IFs at once. SPCAL must be run over and over with you
looping on IF.
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