On Mon, 22 Jun 2020, 10:58 'Jonathan Kliem' via sage-devel, < sage-devel@googlegroups.com> wrote:
> I had a doctest > > sage: ls = [randint(-100,100) for _ in range(4)] > sage: intervals = [[x, x+randint(1,50)] for x in ls] > sage: P = polytopes.hypercube(4, intervals, backend='field') > > which then checked `P` for consistency. However it was somewhat > meaningless (missing `set_random_seed()`) as all entries in `ls` where > positive. It never caught a sign error that we introduced in #28866 > <https://trac.sagemath.org/ticket/28866>. > Adding `set_random_seed` to it, does catch the error. > unless I misunderstand how Sage random numbers are set, by adding an explicit set_random_seed() call you merely went with another bunch of pseudorandom values than these ones you were hitting without it, not that you were fixing a bug. In other words you just hit a more favourable bunch of pseudorandom data. To make such tests more robust, one needs to call them in a loop, without resetting the seed. Then you get a bit more of (pseudo) randomness. > Now this check for consistency certainly wasn't very good in the first > place, as two polyhedra might compare equal, even if one is set up > incorrectly (I just noticed this because of your post, thank you). But it > still would have caught the error even randomness was true randomness. > > You might say, I should have known to add `set_random_seed()` in the first > place, but I'm definitely not the only one who made that mistake and there > are plenty of doctests that claim to test a random event, but they really > test the same event all over and over. > > Am Montag, 22. Juni 2020 11:24:59 UTC+2 schrieb Dima Pasechnik: >> >> >> >> On Mon, 22 Jun 2020, 10:01 'Jonathan Kliem' via sage-devel, < >> sage-...@googlegroups.com> wrote: >> >>> Hi. Could we maybe turn off reproducible "randomness" in doctests by >>> default. There are probably thousands of meaningless doctests because of >>> this. >>> >>> E.g. https://trac.sagemath.org/ticket/29904 >>> >> >> I don't understand, you say there that it went unnoticed due to a too >> easy doctest. I don't see how that one had anything to do with randomness. >> >> Also, could you explain what you mean by "randomness" there. Doctests >> are either tagged "random" (and do matching of answers skipped), >> >> or use random inputs. If a doctest with random input produces >> inconsistent results due to not properly set seeds, it would have been >> caught all along. >> >> >> >>> or the doctests for the namespace function `bernoulli` or the >>> `number_of_partitions` function also in the namespace. >>> >>> Alternatively we should add `set_random_seed` to all of those places. >>> >>> Either way, this might be a huge project, because of possible bugs. >>> >>> Jonathan >>> >>> -- >>> 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 sage-...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/sage-devel/6a5005ec-717e-400c-b253-514f9101bc72o%40googlegroups.com >>> <https://groups.google.com/d/msgid/sage-devel/6a5005ec-717e-400c-b253-514f9101bc72o%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- > 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 sage-devel+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/fcc3910a-e851-4f58-9a26-4eaf3dced699o%40googlegroups.com > <https://groups.google.com/d/msgid/sage-devel/fcc3910a-e851-4f58-9a26-4eaf3dced699o%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- 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 sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/CAAWYfq2TLzN5SwyoEUestmpM%3DoRR1fy_tODU29vdLVCQ5d-%2B8g%40mail.gmail.com.
