+1
On Feb 26, 9:05 pm, Jason Grout <jason-s...@creativetrax.com> wrote:
> Carl Witty wrote:
> >> Anyway, as several have commented, this discussion has taken place
> >> many times before, but having to use
> >> sage: f(x)=x^2
> >> instead of
> >> sage: f=x^2
> >> many times for single-variable symbolic expressions could be very
> >> annoying in the long run, IMHO. Let's not be stultified by trying to
> >> solve computer problems when this is mathematical software; the
> >> distinction between symbolic and callable-symbolic seems different to
> >> me than e.g. formal power series versus actually convergent ones.
> >> FWIW.
>
> > I don't understand this paragraph at all. What problem are you
> > talking about? The problem I see is that people are confused when
> > x(x+1) gives them (x+1); I wouldn't call that a computer problem
> > exactly.
>
> I agree with Carl. I can't count how many times I've thought I would be
> annoyed by being more explicit (i.e., saying f(x)=x^2 instead of f=x^2),
> but it turned out to be not that bad. I also can't count the number of
> times that I've been glad and relieved that I was explicit when I came
> back and read or modified my code (i.e., suppose I want to change
> f=x^2+1 to f=x^2+c to analyze what happens when c changes? Now I have
> to go back through and change all of my code from f(1) to f(x=1)!).
>
> I very much support what pynac is doing, which to my understanding, is this:
>
> f(x,y) = x^2+y # explicitly ordered parameters
> f(-1,2) then gives 3
>
> f=x^2+y # no explicit parameters for f, so they must be specified
> f(x=-1,y=2) then gives 3
> f(-1,2) gives an error
> f.subs(x=-1,y=2) then gives 3
>
> I think having x(x+1) return x+1 is a far greater annoyance than having
> to explicitly write f(x)=x;f(x+1) or x.subs(x=x+1) or even x(x=x+1), all
> of which would hardly be written as an innocent-looking mistake.
>
> I'm always telling my students to not leave off the "dx" in an integral,
> even though there is only one variable, since it is so very important
> when we introduce other parameters or move to multivariable calculus. I
> try to use d/dt notation for derivatives because it is more explicit
> about what variable I'm dealing with, even if initially we only see one
> variable. I think there are great benefits for three more keystrokes
> (i.e., "(x)") in the definition of a function if it makes things much
> more explicit and easy for anyone to understand and takes away
> innocent-looking errors that almost surely will trip new users up.
>
> Gee, the last few paragraphs sound a lot more rant-like than I intended.
> I wasn't trying to pick on anyone. I guess I was just realizing how
> strongly I support what I think are the conventions introduced by pynac.
>
> Thanks,
>
> Jason
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to sage-devel@googlegroups.com
To unsubscribe from this group, send 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
-~----------~----~----~----~------~----~------~--~---
