[PyGiNaC-users] strange behavior with the test suite

[<pp...@fy...>]

Hi,

while playing around with pyginac, I found some strange behavior with
the regression test suite. The reason to this behavior escapes me. 

When running ./run python2.3 bin/checkall.py most of the time 
everything goes ok, but every now and then an error occurs as follows.

*****************************************************************
Failure in example: exam_normal2()
from line #1 of exam_normalization.exam_normal2
Expected: 0
Got:
normal form of  (-y+x)**(-3)*(x**2-y**2)  returned  (y-x)**(-2)*(y+x)  while 
it should be  (-y+x)**(-2)*(y+x)
normal form of  (x**2-y**2)*(-1/2*y+1/2*x)**(-3)  returned  
(y-x)**(-2)*(8*y+8*x)  while it should be  (-y+x)**(-2)*(8*y+8*x)
2
*****************************************************************
1 items had failures:
   1 of   1 in exam_normalization.exam_normal2
***Test Failed*** 1 failures.

To get an idea how often this happens, I ran the test 100 times, giving 43 
fails and 57 clean passes. The interesting part is that when I run

./run python2.3 exam_normalization.py

I am totally unable to reproduce the error above, leading to a guess that this 
might have something to do with bin/checkall.py and/or the doctest module. 
However, I have not been able to point any other reason as to why this would 
be so. I also checked with python 2.4 (Debian-packaged 2.4.1-2) with the same 
results. 

I am using an up-to-date cvs of PyGiNaC, GiNaC 1.3.2, boost.python 1.33.0,
gcc 4.0.2 and python 2.3.5 (all of which except PyGiNaC are the 
Debian-packaged versions). 

So, does anybody have any idea? Can anyone else reproduce this?

Best Regards,
Matti

-- 
Matti Peltomaki, Graduate Student
Laboratory of Physics 
Helsinki University of Technology
040 7576977, room Y308B