Re: Problem with ListPlotVectorField3D
- To: mathgroup at smc.vnet.net
- Subject: [mg56084] Re: Problem with ListPlotVectorField3D
- From: dh <dh at metrohm.ch>
- Date: Fri, 15 Apr 2005 04:47:20 -0400 (EDT)
- References: <d3lrej$s7d$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hello Alain,
Mathematica version 5.1 shows the same behaviour.
It seems that ListPlotVectorField3D tries to be smart and croppes
peripheral vectors where the vector-density is small.
Interestingly, either setting VectorHeads -> False, or better,
PlotRange->All cures the problem.
If anybody has enough time, he could look at the code in
"ListPlotVectorField3D" and let the group know.
Here, instead of AI I would speak of AS (artificial stupidity)
Sincerely, Daniel
Alain Cochard wrote:
> Mathematica 4.0 for Linux
> Copyright 1988-1999 Wolfram Research, Inc.
> -- Motif graphics initialized --
>
> In[1]:= <<Graphics`
>
> Here is a vector field:
>
> In[2]:= vecfield={{{0, 0, 4}, {1, 0, 0}}, {{0, 0, 4}, {1, 0, 0}}, {{0, 0, 4}, {1, 0, 0}},
> {{0, 0, 4}, {1, 0, 0}}, {{0, 0, 4}, {1, 0, 0}}, {{0, 0, 4}, {1, 0, 0}},
> {{0, 0, 4}, {1, 0, 0}}, {{4, 0, 0}, {0, 0, 1}},
> {{2, 2*Sqrt[3], 0}, {0, 0, 1/2}}, {{-2, 2*Sqrt[3], 0}, {0, 0, -1/2}},
> {{-4, 0, 0}, {0, 0, -1}}, {{-2, -2*Sqrt[3], 0}, {0, 0, -1/2}},
> {{2, -2*Sqrt[3], 0}, {0, 0, 1/2}}, {{4, 0, 0}, {0, 0, 1}},
> {{0, 0, -4}, {-1, 0, 0}}, {{0, 0, -4}, {-1, 0, 0}},
> {{0, 0, -4}, {-1, 0, 0}}, {{0, 0, -4}, {-1, 0, 0}},
> {{0, 0, -4}, {-1, 0, 0}}, {{0, 0, -4}, {-1, 0, 0}}, {{0, 0, -4}, {-1, 0, 0}}};
>
> In the following I get only 4 arrows:
>
> In[3]:= ListPlotVectorField3D[vecfield, VectorHeads -> True]
>
> Out[3]= -Graphics3D-
>
> In the following I get all the expected arrows (but without the
> heads). I could stop here and ask why but ...
>
> In[4]:= ListPlotVectorField3D[vecfield]
>
> Out[4]= -Graphics3D-
>
> ... in the following, I do get all the expected arrows with heads,
> but why? As I understand, Union is only supposed to sort and
> remove duplicates, so what difference does it make as far as
> ListPlotVectorField3D is concerned? Plus I have experimented with
> "some amount" of duplication without problem.
>
> In[5]:= ListPlotVectorField3D[Union[vecfield],
> VectorHeads -> True]
>
> Out[5]= -Graphics3D-
>
>
> Am I doing something wrong?
> Thanks,
> Alain
>