[GiNaC-list] Possible bug in factor()

tluthe at physik.uni-bielefeld.de tluthe at physik.uni-bielefeld.de
Wed May 14 14:20:12 CEST 2014


there appears to be a bug in the multivariate  factor() routine. For some
expressions it seems to get stuck in an infinite loop, without any result
or error messages appearing. The simplest expression I could find to
reproduce this behaviour consistently is the expanded form of
(3*x+2*y)*(x+y+x*y). For some other expressions (e.g. (x+2*y)*(x+y+x*y))
the problem occurs randomly, but not all the time. I'm guessing this is
due to the randomness of the internal ordering of symbols. A minimal
example code exhibiting the problem is attached.

I've reproduced this bevahiour on openSuse and Ubuntu machines using GiNaC
1.6.2 and CLN 1.3.2.

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