Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2000
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2000

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: 3D plot of discontinuous function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg24804] Re: [mg24779] 3D plot of discontinuous function
  • From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
  • Date: Sun, 13 Aug 2000 03:16:43 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

A small addition to the previous method. The graphic objects constructed in
my previous solution are "illegitimate", in the sense that they contain the
non-numerical vlaue "Indeterminate" where a number is expacted. However, we
can easily convert them to perfectly legitimate grahic objects and even
obtain a better picture as follows:

p1 = DeleteCases[
      DeleteCases[Graphics3D[p1], Indeterminate,
        Infinity], {_?NumberQ, _?NumberQ}, Infinity];

p2 = DeleteCases[
      DeleteCases[Graphics3D[p2], Indeterminate,
        Infinity], {_?NumberQ, _?NumberQ}, Infinity];


We can now turn on the error messages with:

In[27]:=
On[Plot3D::"plnc"]
In[28]:=
On[Plot3D::"gval"]
In[29]:=
On[Graphics3D::"nlist3"]

Evaluating 

In[30]:=
Show[p1, p2, DisplayFunction -> $DisplayFunction]

will produce a slightly better picture without any error messages.

Andrzej


on 8/10/00 7:51 PM, Andrzej Kozlowski at andrzej at tuins.ac.jp wrote:

> Here is the simplest method I can think of. I will use your example.
> 
> The method woudl normally produce several error messags, so we first supress
> them:
> 
> In[1]:=
> Off[Plot3D::"plnc"]
> In[2]:=
> Off[Plot3D::"gval"]
> In[3]:=
> Off[Graphics3D::"nlist3"]
> 
> 
> Now, we define two functions f and g by:
> 
> In[4]:=
> f[x_, y_] := If[x > y, 1, Indeterminate]
> 
> In[5]:=
> g[x_, y_] := If[x < y, 0, Indeterminate]
> 
> and two graphs:
> 
> In[6]:=
> p1 = Plot3D[f[x, y], {x, -1, 1}, {y, -1, 1}, PlotPoints -> 50,
> DisplayFunction -> Identity];
> 
> In[7]:=
> p2 = Plot3D[g[x, y], {x, -1, 1}, {y, -1, 1},PlotPoints -> 50, DisplayFunction
> -> Identity];
> 
> Now 
> 
> In[8]:=
> Show[p1, p2, ViewPoint -> {-5.339, -2.848, 2.830},
> DisplayFunction -> $DisplayFunction]
> 
> produces a reasonable representation of a discontinuous function.
> 



  • Prev by Date: enhanced ArcCos[] ?
  • Next by Date: Custom build for MathLink examples in MS Visual Studio 6.0
  • Previous by thread: 3D plot of discontinuous function
  • Next by thread: Re: 3D plot of discontinuous function