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billv |
01/26/2011 12:56AM (Read 1981 times)
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Status: offline
Registered: 01/25/2011
Posts: 2
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I get the message "ERROR: floating point invalid operation" while trying to run TRANSFORM on images. identify, reidentify, and fitcoords have all run without problems. I understand that this error arises from some operation fault, but the images do not have NaN's or unusually large or small values. Could the problem be related to bug # 559? (I'm not using log resampling though.)I'm running v2.14 on a MacBook Pro under Snow Leopard.
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fitz |
01/26/2011 12:56AM
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Status: offline
Registered: 09/30/2005
Posts: 4040
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It is highly likely that Bug #559 is a resolved issue and your problem comes about because of either something in the data/header or your parameter values. There is no known issue with the task, if you could post your image and parameters (i.e. a 'dpar transform" output) to the anonftp at ftp://iraf.noao.edu/pub we'll see if we can reproduce and debug the problem.
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billv |
01/26/2011 12:56AM
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Status: offline
Registered: 01/25/2011
Posts: 2
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The image has been posted to the anonftp site, along with the parameters and the database files.
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fitz |
01/26/2011 12:56AM
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Status: offline
Registered: 09/30/2005
Posts: 4040
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I'm gonna pass this to Frank for resolution. I can reproduce the problem which comes down to essentially a divide-by-zero problem when initializing the task.
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valdes |
01/26/2011 12:56AM
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Status: offline
Registered: 11/11/2005
Posts: 728
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Hi,The problem is the surface you created with fitcoords is constant (i.e. maps all points to the same value) on one axis. The surface should have a minimum order of 2 (a linear function) for each axis. There are also potential problems with fitting the 2D dispersion/spatial function when the sampling is not very uniform (in your case there are only a few lines) and the fit could do funny things where it becomes poorly constrained.I redid a fitcoords solution with orders of 2 and it worked. All the attempts you made used an order of 1 for the spatial part. I have modified fitcoords for a future release such that it is not possible to set the orders to 1 (or less) in fitcoords.I am not 100% certain that this will avoid transform encountering a arithmetic exception because the surface inversion process is tricky and if functions become non-monotonic it is possible for zero derivatives to result in a zero denominator. I added some checks for this but it did not stop arithmetic exceptions with the case your provided.So go back to fitcoords and use a minimum order of 2 for either axis.Frank Valdes
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