I opened http://code.google.com/p/sympy/issues/detail?id=3256 for this.
Aaron Meurer On Wed, May 2, 2012 at 4:15 PM, Aaron Meurer <[email protected]> wrote: > 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.
