Many RUBI rules actually consist on applying that kind of algorithms. The trick with those algorithms is that sometimes they help, and sometimes they hurt (in the sense that you get something that is actually harder to integrate).
One of the important things about RUBI that many people forget about is that it not only is able to integrate more expressions than Mathematica/Maple/Maxima... (and usually does it faster), but that it also often produces "better" output (in the sense of more compact expressions and/or fewer discontinuity problems). In general, each rule of RUBI turns the expression into something simpler, so even if you don't have the full set of rules, you can use the ones you have as a preprocessing step for other kinds of algorithms. El martes, 28 de febrero de 2017, 11:14:13 (UTC+1), parisse escribió: > > My opinion is that it's better to add new algorithms for failures than > rules. Of course adding rules will add a few success, but it's not like > adding algorithms that can be combined together like integration by part > and partial fraction decomposition or integration of rational fraction of x > and sqrt(polynomial of degree 2). But perhaps I misunderstand Rubi, and it > does that inside Mathematica? > > Le mardi 28 février 2017 10:50:50 UTC+1, mmarco a écrit : >> >> >>> Back to the original proposal. Certainly rules can't catch all cases >>> either. Doesn't this call for a combined approach? As soon as we have rules >>> in Sage they should be called before the best algorithm we have. The >>> default then IMO should be "special rules + Maxima" instead of Maxima alone. >>> >>> Regards, >>> >> >> I agree with that approach, specially because it allows adding rules >> incrementally. Even if we don't have all the set of RUBI rules, having a >> few of them could be an improvement. >> > -- 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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
