I've been tracking this in a debugger. There is a bug in the Wang factorization algorithm. The difference comes at line 920 of factortools.py, where a random number is used. I can try and see if I can figure this out, but it probably won't be easy without understanding of the algorithm.
Mateusz, can you look at this? For reference, the input to dmp_zz_wang is f = [[[mpz(2)]], [[]], [[mpz(1), mpz(-1)], [mpz(-1), mpz(1), mpz(0)]]], u = 2, K = ZZ, mod=None. Aaron Meurer On Wed, May 2, 2012 at 3:47 PM, Aaron Meurer <[email protected]> wrote: > I can reproduce this with ./bin/test --seed=13604685 > sympy/polys/tests/test_polyroots.py > > I put in some print statements, and it seems that roots is returning > {1: 1, y/2 - sqrt(8*x**2 + y**2 - 2*y + 1)/2 + 1/2: 0, y/2 + > sqrt(8*x**2 + y**2 - 2*y + 1)/2 + 1/2: 0} when it should be returning > {1: 1, y/2 - sqrt(8*x**2 + y**2 - 2*y + 1)/2 + 1/2: 1, y/2 + > sqrt(8*x**2 + y**2 - 2*y + 1)/2 + 1/2: 1} (the difference is the > values). > > Aaron Meurer > > On Wed, May 2, 2012 at 3:05 PM, Joachim Durchholz <[email protected]> wrote: >> I just got a nonreproducible assertion failure. >> I.e. bin/test (with no additional options) gave me an AssertionError on line >> 293 of sympy/polys/tests/test_polyroots.py. >> Sure enough, that line compares two hashes for equality. >> >> Rerunning the test in isolation did not reproduce the error, nor did >> rerunning the test suite in full reproduce. >> It does reproduce with the right random seed, 13604685, on my current >> workdir and on current master. >> >> Here's the first few lines of bin/test output: >> >> ============================= test process starts >> ============================== >> executable: /usr/bin/python (2.7.3-final-0) >> architecture: 64-bit >> cache: yes >> ground types: python >> random seed: 13604685 >> >> What now? >> >> -- >> You received this message because you are subscribed to the Google Groups >> "sympy" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/sympy?hl=en. >> -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
