Re: weird behavior when plotting multiple functions in 6.0
- To: mathgroup at smc.vnet.net
- Subject: [mg76089] Re: [mg76050] weird behavior when plotting multiple functions in 6.0
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Wed, 16 May 2007 05:25:49 -0400 (EDT)
- References: <200705150859.EAA17134@smc.vnet.net>
On 15 May 2007, at 17:59, Roman wrote:
> Hello all:
>
> When I plot
> Plot[{Sin[x], Cos[x]}, {x, 0, 4*Pi}]
> I get two curves: one blue, one red.
>
> But when I do
> f[x_] = {Sin[x], Cos[x]};
> Plot[f[x], {x, 0, 4*Pi}]
> both curves are blue. It is as if at some level Mathematica does not
> understand that I'm actually plotting two curves at a time, and uses
> the first color specification (blue) for both curves.
>
> This is particularly annoying when you want to play with plot styles,
> for example filling instructions, like
> Filling -> {1 -> -1, 2 -> 1}
> which works in the first example but not in the second one.
>
> Has anyone figured out a workaround for this one?
>
> Thanks!
> Roman.
>
>
This is completely reasonable. Unless Mathemaitca sees and explicit
List as the Head of the argument to be plotted it will use the
algorithm for plotting a single function. Actually, this shows an
interesting change compared with Mathematica 5.2. In Mathematica 5.2
your code will produce no plot at all: but only error messages. In
Mathematica 6 you actually get a plot of two fucntions but colored
inthe same way. In both versions the correct thing to do is:
f[x_] = {Sin[x], Cos[x]};
Plot[Evaluate[f[x]], {x, 0, 4*Pi}]
Andrzej Kozlowski
- References:
- weird behavior when plotting multiple functions in 6.0
- From: Roman <rschmied@gmail.com>
- weird behavior when plotting multiple functions in 6.0