On Sat, 14 Mar 2009 11:45:13 -0700
William Stein <wst...@gmail.com> wrote:
>
> On Sat, Mar 14, 2009 at 11:37 AM, Burcin Erocal <bur...@erocal.org>
> wrote:
> >
> > On Sat, 14 Mar 2009 13:18:40 -0500
> > Jason Grout <jason-s...@creativetrax.com> wrote:
> >
> >>
> >> William Stein wrote:
> >> > On Sat, Mar 14, 2009 at 11:09 AM, Jason Grout
> >> > <jason-s...@creativetrax.com> wrote:
> >> >> William Stein wrote:
> >> >>> On Sat, Mar 14, 2009 at 10:29 AM, Carl Witty
> >> >>> <carl.wi...@gmail.com> wrote:
> >> >>>> 2) plotting
> >> >>>> A lot of the plotting code is willing to pick variable names
> >> >>>> (in alphabetical order) if names aren't given in the plot
> >> >>>> ranges. For instance, this is a doctest in plot.py:
> >> >>>> sage: f = sin(x^2 + y^2)*cos(x)*sin(y)
> >> >>>> sage: c = contour_plot(f, (-4, 4), (-4, 4),
> >> >>>> plot_points=100) This will be deprecated, but any of the
> >> >>>> following will work:
> >> >>> -1
> >> >>>
> >> >>> I'm strongly against deprecating anything like this for
> >> >>> plotting, since there are clear labeled axes in the plot.
> >> >>>
> >> >>>> sage: c = contour_plot(f, (x, -4, 4), (y, -4, 4),
> >> >>>> plot_points=100) sage: c = contour_plot(f.function(x, y), (-4,
> >> >>>> 4), (-4, 4), plot_points=100) sage: c = contour_plot(lambda
> >> >>>> x,y: f(x=x,y=y), (-4, 4), (-4, 4), plot_points=100)
> >> >>>>
> >> >>
> >> >> I'm just as strongly for the deprecation. The axes are *not*
> >> >> clearly labeled: it's not clear which axis is which because
> >> >> there are no variable names next to the axes. Even if we fixed
> >> >> that issue, though, it is not clear to the user how to switch
> >> >> the axes if they are opposite from what they want.
> >> >> contour_plot(f, (x,-4,4), (y,-4,4)) makes it intuitive that if
> >> >> you want to swap roles of the axes, you swap the ranges.
> >> >> Explicit is better than implicit, I feel, in this case.
> >> >>
> >> >
> >> > Well then we disagree. There is a very standard convention in
> >> > math to have the x axis in one spot, then the y-axis.
> >>
> >> What happens when you have variables u and v? Or a and b? Or t
> >> and s (oops, I mean s and t; I forgot the alphabetical order; see?
> >> it's easy to mess up; but t is often the x-axis, regardless of
> >> what the other variable is called, even if it is alphabetically
> >> smaller... :). What about variables some_long_name and
> >> some_long_mame? It's much harder then to figure out which gets
> >> magically picked as the x-axis.
> >
> > I agree with Jason here. I think the variables should be specified
> > explicitly.
> >
> > William, shall we treat the case where the only variables in the
> > expression is x and y specially, and allow not specifying the
> > variables for the axis then? I think this makes the notation
> > confusing and inconsistent.
> >
>
> I have never ever even once heard of somebody complaining or being
> serious confused because these pop up a plot:
>
> sage:
> sage: plot(sin(u), (-3,3))
> sage: plot3d(x^2 + y^2, (0,3), (-2,3))
>
> I have frequently seen and heard of people being confused by
>
> sage: x(5)
> 5
The latter option also seems harmless when seen only in that context,
but more complicated examples lead to problems. Many people got
confused with that syntax over time, so we decided to deprecate it.
It is a similar situation for the plot commands. Many people have
complained about the inconsistencies in Sage's plotting interface.
Looking at MMA's plot commands, only this syntax is accepted:
Plot[Sin[x], {x, 0, Pi}]
Note the explicit variable name.
I think we should try to make the syntax uniform for all the plot
functions, and ask the user to specify the variable in every case.
(This means deprecating the xmin/xmax parameters of the plot function
as well.)
Thanks.
Burcin
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