id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
31585,Wrong result due to integer overflow (in pynac?),Dave Morris,,"Volker Braun pointed out in ticket:31479#comment:12 that sage gives the following wrong answer on a 32-bit machine after the bug-fix patch of #31479 is applied:
{{{
sage: a,b,c,d = var(""a b c d"")
sage: ((a + b + c)^30 * (3*b + d - 5/d)^3).expand().subs(a=0,b=2,c=-1)
d^3 + 18*d^2 + 1739461754973*d - 8697308774865/d + 450/d^2 - 125/d^3 + 36
}}}
This answer is congruent modulo `2^32` to `d^3 + 18*d^2 + 93*d - 465/d + 450/d^2 - 125/d^3 + 36`, which is the correct answer, so it seems clear that the problem comes from an integer overflow error. Perhaps the overflow error can also be produced on a 64-bit machine.",defect,closed,critical,sage-9.4,symbolics,fixed,"integer overflow, pynac",,,"Dave Morris, Matthias Koeppe",Dima Pasechnik,N/A,,eba0a9cc1cca15a9c39d84e7aaac1c762de3591f,eba0a9cc1cca15a9c39d84e7aaac1c762de3591f,#31694,