Exceptions thrown when reading Lib80x TSL files about papillon-ndl HOT 1 CLOSED

So FRENDY does seem to behave better than NJOY, as I have yet to see a TSL ACE produced by FRENDY which has a negative PDF (though that doesn't mean it isn't possible). That being said, after testing all of the TSLs at all temperatures in Lib80x, it appeared that all of the negative values had a magnitude smaller than 1.E-15, and most were to the order of 1.E-20. From this, I now check the magnitude of the negative value: if the value has a magnitude smaller than 1.E-15, it is simply set to zero, otherwise the exception is still thrown. This maybe isn't the ideal solution, but if PNDL is going to be able to read/use any TSLs produced with NJOY, it seems necessary.

After correcting this problem, other errors were encountered, as there were many instances of the equiprobable discrete angles not being sorted. This could be a problem when performing the smearing operation. To fix this, I simply sort the angles if they are not sorted, and then continue with the other checks (like making sure all angles are in [-1, 1], etc.). While FRENDY didn't seem to produce negative PDF values, it did generate some files where the cosines also were not sorted.

With these two modifications, it is now possible to read all of the TSLs from Lib80x, without any exceptions being thrown.

from papillon-ndl.