Yikes! https://github.com/sagemath/sage/pull/66
On Tue, Nov 8, 2016 at 12:06 PM, Mathijs van de Nes <[email protected]> wrote: > The function square_root_mod_prime from sage.rings.finite_rings.integer_mod > may produce an incorrect result. > > Example: > In [1]: mod(100, 5^7).sqrt()^2 > Out[1]: 15725 > In [2]: square_root_mod_prime_power(mod(100, 5^7), 5, 7)^2 > Out[2]: 15725 > > The expected result is 100 instead of 15725. > > Tracing the steps I believe the error is at line 3726 of > src/sage/rings/finite_rings/integer_mod.pyx > Link: > https://github.com/sagemath/sage/blob/1b1e6f608d1ef8ee664bb19e991efbbc68cbd51f/src/sage/rings/finite_rings/integer_mod.pyx#L3726 > > In this case, n = 2. I do not understand this part of the algorithm, but it > appears that increasing the bound by one such that n = 3 does produce the > correct answer. > > version(): SageMath version 7.4, Release Date: 2016-10-18 > > Kind regards, > > Mathijs van de Nes > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
