On Friday, November 7, 2014 1:43:13 PM UTC-8, Thierry (sage-googlesucks@xxx) wrote: > > > Incidentally I observe that Sympy has the same behavior, so we can't > > just nick their factoring algorithm -- maybe some other package we can > > try the same example to see if any of them handle it quickly? > > How did you observe the same behaviour for sympy ? >
I'm pretty sure Robert is alluding to the fact that the factoring in sympy is also slow: sage: %time (exp(256*(x+1)) - 1)._sympy_().factor() CPU times: user 20.3 s, sys: 11 ms, total: 20.3 s Wall time: 20.3 s (E*exp(x) - 1)*(E*exp(x) + 1)*(exp(2)*exp(2*x) + 1)*(exp(4)*exp(4*x) + 1)*(exp(8)*exp(8*x) + 1)*(exp(16)*exp(16*x) + 1)*(exp(32)*exp(32*x) + 1)*(exp(64)*exp(64*x) + 1)*(exp(128)*exp(128*x) + 1) Apparently, sympy doesn't try factoring as part of its zero test (or at least arrives at a definitive answer for this example). However, note that the answers of sympy and maxima are different: sympy says "false" because the expression is not identically 0 and maxima says "unknown" because the expression is not identically 0, but is 0 for some values of x (or at least I hope that is what maxima is doing). So maxima is determining more information. -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
