On Tue, Aug 18, 2009 at 4:56 PM, rjf<fate...@gmail.com> wrote: > > > At the risk of providing some information about what is probably going > on, > let me suggest the following. > > 1. The expand() command in Maxima is almost always the wrong thing to > do if the argument is a polynomial. > ratexpand() or ratsimp() or rat() will be much faster. I suspect > that in your timings of Maxima, the major > contributor may be expand. > > 2. This is not a good test of polynomial factoring, because it does > uses only a trivial part of the algorithm, > and that is the square-free factoring part, that consists of computing > P' a derivative of P and a gcd(P,P'). > > Mostly you are testing the gcd program, but only the case of the gcd > program for gcd(a,b) where, almost all > the time, a divides b. So you are not even testing the gcd program, > you are testing polynomial division with remainder. > > Now if that is what you want to test, fine. If you want to test > polynomial factoring, there is a substantial > literature on how to choose polynomials that are difficult to factor. > Especially large degree is not really necessary. > > While it is only a speculation on my part, I think what you may also > be timing is the conversion of > relatively large character strings, at least in some cases. > > I hope you can straighten this out before you present your results at > your conference.
Thanks for joining the discussion. My presentation is on Thursday, so I'll try to send my slides to sage+sympy lists tomorrow, so that you can look at it and see if I say something that is unfair to Maxima, or any other program. Does anyone know some real life applications of factor(<some polynomial>)? E.g. simplifications, like canceling common factors from nominator/denominator, but is there anything else? I would like to use some real life application as a benchmark, I just don't know any. Ondrej --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
