On Thu, Jun 28, 2012 at 8:06 PM, Nathaniel Smith <n...@pobox.com> wrote: > On Thu, Jun 28, 2012 at 7:13 AM, Pierre Haessig > <pierre.haes...@crans.org> wrote: >> Hi Nathaniel, >> Le 27/06/2012 20:22, Nathaniel Smith a écrit : >>> According to the Travis-CI build logs, this code produces >>> non-deterministic behaviour in master: >> You mean non-deterministic across different builds, not across different >> executions on the same build, right ? >> >> I just ran a small loop : >> >> N = 10000 >> N_good = 0 >> for i in range(N): >> a = np.arange(5) >> a[:3] = a[2:] >> if (a == [2,3,4,3,4]).all(): >> N_good += 1 >> print 'good result : %d/%d' % (N_good, N) >> >> and got 100 % good replication. > > Yes, the current hypothesis is that there is one particular Travis-CI > machine on which memcpy goes backwards, and so the test fails whenever > the build gets assigned to that machine. (Apparently this is actually > faster on some CPUs, and new versions of glibc are known to exploit > this.)
see also this: https://bugzilla.redhat.com/show_bug.cgi?id=638477 David _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
