Problem with ListPlotVectorField3D

*To*: mathgroup at smc.vnet.net*Subject*: [mg56060] Problem with ListPlotVectorField3D*From*: Alain Cochard <alain at geophysik.uni-muenchen.de>*Date*: Thu, 14 Apr 2005 08:55:56 -0400 (EDT)*Reply-to*: alain at geophysik.uni-muenchen.de*Sender*: owner-wri-mathgroup at wolfram.com

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