On Sep 6, 2009, at 3:10 PM, William Stein wrote: > On Sun, Sep 6, 2009 at 3:00 PM, Burcin Erocal<bur...@erocal.org> > wrote: >> >> On Sun, 6 Sep 2009 14:35:24 -0700 >> William Stein <wst...@gmail.com> wrote: >> >>> I think the vote from this dicussion for Sage was to make it so >>> ln and >>> log are both supported and "log" is base e by default. So in the >>> future we'll have: >>> >>> sage: ln(x) >>> ln(x) >>> sage: log(x) >>> log(x) >>> >>> That should make most people happy. >> >> How do you think this should be implemented? > > Oh crap, I have no clue! > >> - define two independent symbolic functions that share the same code >> for evaluation >> >> - have a hidden parameter to indicate the printing preference in the >> SFunction subclass that implements log >> >> The first option means we have to normalize to one of these before >> any >> nontrivial processing, e.g., simplification, integral transforms, >> integration, etc. >> >> Second one makes the trivial equality checking for log(x) == ln(x) >> difficult. > > Of these two options, the second sounds better.
I agree. > Right now we have > > sage: type(log) > <type 'function'> > > Really it should be > > sage: type(log) > <class 'sage.functions.log.Function_log'> > > which you can get by doing: > > sage: log = log(x).operator() > > Anyway, log is just some Python class with a name() method: > sage: log.name() > 'log' > > If we also instantiate the class but with name returning 'ln', that > might work. Whenever it made a round trip to maxima, etc. it would get "normalized" back to log. Also, would sage: log(x) + ln(x) 2*log(x) Just declaring ln = log, and not having ln in the output (unless perhaps some special typesetting option was on) seems like the simplest case to me. Having ln preserved sometimes, but not all the time, is just asking for a complicated system and user confusion. - Robert --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
