ZeroDivisionError when computing molecular descriptors

[lorenzoFabbri]

I'm trying to use PyBioMed to compute protein molecular descriptors. Everything works just fine except that for some sequences (like "RPDDEWY"), I encounter the following error:

ZeroDivisionError: integer division or modulo by zero.

Specifically, this happens when calling GetPAAC:

descriptors = Pyprotein.PyProtein(sequence)
descriptors.GetPAAC()

The last line of the Traceback points to _GetSequenceOrderCorrelationFactor but if I call just that function it works just fine. If I instead call either _GetPseudoAAC or _GetPseudoAAC1, I get the same error.

[lorenzoFabbri]

I see now that _GetSequenceOrderCorrelationFactor is called many times and that the sequence provided is too short.

At the moment, I changed the value of lamda inside all the functions (Pyprotein.py and PseudoAAC) and this solves the problem. I wonder though whether changing its value (to 5), will cause any other problem in the descriptors themselves. Thanks.

[ifyoungnet]

@lorenzoFabbri
Thanks for your comments.
lamda factor reflects the rank of correlation and is a non-Negative integer, such as 15.
Note that (1)lamda should NOT be larger than the length of input protein sequence;
(2) lamda must be non-Negative integer, such as 0, 1, 2, ...; (3) when lamda =0, the
output of PseAA server is the 20-D amino acid composition.