filed a bug in https://github.com/sagemath/sage/issues/35529
On Mon, Apr 17, 2023 at 9:42 AM Dima Pasechnik <dimp...@gmail.com> wrote: > > > On Mon, Apr 17, 2023 at 7:40 AM Tracy Hall <h.tr...@gmail.com> wrote: > >> (error present at least from SageMath 8.2 until SageMath 9.8) >> > > in 10.0.beta9 one gets > > sage: BG = BraidGroup(5) > sage: b = BG([3, 3, 4, 3, 3, 2, 1, 4, 3, 2]); b > s2^2*s3*s2^2*s1*s0*s3*s2*s1 > sage: b.centralizer() > double free or corruption (out) > > (and then it hangs) > > > > >> >> On Monday, April 17, 2023 at 12:36:41 AM UTC-6 Tracy Hall wrote: >> >>> Attempting to calculate the centralizer of a particular element of the >>> braid group on 5 strands causes a segmentation fault. >>> >>> sage: BG = BraidGroup(5); BG >>> Braid group on 5 strands >>> >>> sage: b = BG([3, 3, 4, 3, 3, 2, 1, 4, 3, 2]); b >>> s2^2*s3*s2^2*s1*s0*s3*s2*s1 >>> >>> sage: b.left_normal_form() >>> (1, s2*s3*s2, s2*s1*s0*s3*s2*s1*s0) >>> >>> sage: b.ultra_summit_set() >>> [[s0*s1*s0*s2*s1*s0*s3*s2*s1*s0]] >>> >>> sage: b.is_pseudoanosov() >>> False >>> >>> sage: b.centralizer() >>> >>> --------------------------------------------------------------------------- >>> SignalError Traceback (most recent call >>> last) >>> Cell In [7], line 1 >>> ----> 1 b.centralizer() >>> File /ext/sage/9.8/src/sage/groups/braid.py:1546, in >>> Braid.centralizer(self) >>> 1534 def centralizer(self): >>> 1535 """ >>> 1536 Return a list of generators of the centralizer of the braid. >>> 1537 >>> (...) >>> 1544 >>> 1545 """ >>> -> 1546 l = centralizer(self) >>> 1547 B = self.parent() >>> 1548 return [B._element_from_libbraiding(b) for b in l] >>> File /ext/sage/9.8/src/sage/libs/braiding.pyx:233, in >>> sage.libs.braiding.centralizer() >>> 231 return [[[0], [i+1, nstrands - i -1]] for i in >>> range(nstrands//2-1)] + [[[0], [nstrands//2]]] >>> 232 l = braid.Tietze() >>> --> 233 sig_on() >>> 234 cdef list[list[list[int]]] rop = CentralizerGenerators(nstrands, >>> l) >>> 235 sig_off() >>> SignalError: Segmentation fault >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "sage-support" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to sage-support+unsubscr...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sage-support/be9455fb-ab03-43bb-93f2-dd3a2c43186bn%40googlegroups.com >> <https://groups.google.com/d/msgid/sage-support/be9455fb-ab03-43bb-93f2-dd3a2c43186bn%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/CAAWYfq1ZRTpr6z156Y%2BfeaRp%3D7sJa-u4BCUWKg4KffSVaN8vRg%40mail.gmail.com.
