On Sat, Mar 14, 2009 at 12:07 PM, Jason Grout
<jason-s...@creativetrax.com> wrote:
>
> Jason Grout wrote:
>> William Stein 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
>>>
>>>
>>> Just for historical perspective, when plot was written there was no
>>> symbolic ring in sage and no symbolic variables, so putting (x,0,3)
>>> made no sense...
>>
>> That makes sense, given the history. We have them now, so we can be
>> better about that sort of thing.
>>
>> From #sage-devel IRC:
>>
>> [13:48] <wstein2> I would now consider proposing that now that we have
>> symbolics we try to renormalize things to be very similar to mathematica
>> again.
>> [13:48] <jason--> I agree.
>> [snip..]
>> [13:48] <wstein2> If you propose it on sage-devel, i'll write back and
>> agree, conceeding my point.
>>
>>
>> To be clear, I think we are agreeing that Carl Witty's proposal point
>> (2) is okay.
>>
>
> Also, on IRC, the "xmin", "xmax", "ymin", and "ymax" parameters were
> brought up. These get confusing when different variables are used. A
> more MMA-oriented way to do these is to make names that don't assume the
> names "x" and "y". It would be great to change these to maybe something
> like:
>
> hmin, hmax for horizontal min/max
>
> vmin,vmax for vertical min/max
>
> MMA has a PlotRange option that sets the horizontal and vertical ranges
> (i.e., PlotRange->{-2,2} for vertical range of a Plot, or PlotRange->{
> {-2,2}, {-3,3}} for Show ).
>
> I think having a plot_range option with similar semantics to the MMA one
> would be okay too.
+1 -- at a bare minimum we should have plot_range. I would I think
be happy having only that.
xmin/xmax should stick around for a long time (deprecated-ish) though,
since they have been used in so much existing code!
william
-- William
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