On Fri, 27 Aug 2021, 20:45 William Stein, <wst...@gmail.com> wrote: > On Fri, Aug 27, 2021 at 2:21 AM Dima Pasechnik <dimp...@gmail.com> wrote: > > How are these integrals above computed by Sage? Via Maxima, or in some > > other way? > > When I implemented this, they were all computed in Maxima by default, > unless otherwise requested. Thus symbolic integration may be > orthogonal to the pynac vs symengine discussion. You can browse some > of the beautiful decades(!) old Maxima lisp code for integration > starting here: > https://github.com/andrejv/maxima/blob/master/src/defint.lisp > I'm cc'ing RJF in case he has some perspective to add. > > Pynac has a lot of I think nontrivial efficient hooks back into Sage > for working with various data types, and doing things like equality > testing, fast evaluation of expression (fast_float, etc.), so it'll be > quite a lot of work to switch away from. I created pynac as a fork > of ginac only because there was a very talented student trying for a > year to do something similar more from scratch in Cython, and I got > impatient. It's too bad pynac is unmaintained now; I think the basic > idea wasn't so bad, and the performance was pretty good. >
ginac, in fact, continues to be maintained, and even developed, after a long hiatus. But the pynac fork diverged from it long time ago, and naturally backporting new code/fixes from ginac appears to be very hard. > -- William > > > > and sympy.integrate(*map(sympify, (dgamma(x, a, b), (x, 0, > 1)))).simplify()._sage_() never returns. Res ipsa loquitur… > > > > > > BTW : many Sympy integrations result in Sympy’s Piecewise expressions > (correctly transcripted as Sage’s cases) involving logical expressions > using Sympy’s symbolic logical functions/operators And, Or and Not, which > have currently no equivalent in Sage (but see Trac#31911…) > > > > > > -- > > > 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/eb1cfbc2-3339-4031-8e24-fc0ceca307ben%40googlegroups.com > . > > > > -- > > 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/CAAWYfq0kcukS4RfSJ4oaxNM0yZHt3n5zFvdGk%2BuRr34M6YZ2SA%40mail.gmail.com > . > > > > -- > William (http://wstein.org) > > -- > 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/CACLE5GBhpFYXvbfqE8u-AU42cdDN8dQP320znbPHRkvivPXVRA%40mail.gmail.com > . > -- 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/CAAWYfq3epDa2EDNE9xviZ%2BRuiUXfh56YfcEFOtCB9D0EjH-0pQ%40mail.gmail.com.
