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  1. Data Management
  2. DM-15638

Fix DcrCoadd subfilter order

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      Description

      The measured spectrum of simulated sources that are recovered after modeling with DcrCoadds appears to be inverted from the input simulations. There appears to be a bug in either the sign of the direction of DCR in the simulations or the modeling code, or there is a bug later when assigning wavelength ranges to DCR subfilters.

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            sullivan Ian Sullivan added a comment -

            Resolution: The order of the DrModel subfilters was reversed, which was due to the calculated shift due to DCR having the wrong sign. There were several bugs that worked together in this: the rotation calculation was written for a flipped WCS, but if a non-flipped WCS was supplied it would be off by -90 degrees. Then, afwGeom.Extent2D() takes arguments in the order X,Y but had been supplied in the order Y,X, so that had been off by another 90 degrees. Finally, DCR is mostly symmetric around the center of the band, so everything still mostly worked even though the shift in each band had the wrong sign.

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            sullivan Ian Sullivan added a comment - Resolution: The order of the DrModel subfilters was reversed, which was due to the calculated shift due to DCR having the wrong sign. There were several bugs that worked together in this: the rotation calculation was written for a flipped WCS, but if a non-flipped WCS was supplied it would be off by -90 degrees. Then, afwGeom.Extent2D() takes arguments in the order X,Y but had been supplied in the order Y,X, so that had been off by another 90 degrees. Finally, DCR is mostly symmetric around the center of the band, so everything still mostly worked even though the shift in each band had the wrong sign.
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            Parejkoj John Parejko added a comment -

            Thanks for updating the tests: I left one more comment, but once you've dealt with that this is good to merge.

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            Parejkoj John Parejko added a comment - Thanks for updating the tests: I left one more comment, but once you've dealt with that this is good to merge.

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              • Assignee:
                sullivan Ian Sullivan
                Reporter:
                sullivan Ian Sullivan
                Reviewers:
                John Parejko
                Watchers:
                Ian Sullivan, John Parejko, John Swinbank
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                  Updated:
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