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Re: Interpolation of 3D data problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg16541] Re: Interpolation of 3D data problem
  • From: "David Keith" <dkeith at sarif.com>
  • Date: Tue, 16 Mar 1999 04:00:17 -0500
  • Organization: Sarif
  • References: <7c5bqk$7s5@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

I have also had such problems. In the past I have assumed they derived from
having more than one value in the range specified for the same value in the
domain. That is, the relation defined by the data is not single valued, so
Interpolation[] doesn't know what to do. I don't see that in this data so I
am also interested in an explanation.

David


Jan Krupa <krupa at alpha.sggw.waw.pl> wrote in article
<7c5bqk$7s5 at smc.vnet.net>...
> I would like to interpolate (approximate) the following data (3D):
> 
> In[1]:=d = {{3.53,35.01,58.66},
>   {9.15,40.39,6.17},
>   {12.52,94.88,86.27},
>   {16.71,51.29,6.52},
>   {16.88,24.18,46.21},
>   {24.9,11.37,93.38},
>   {25.28,56.62,80.69},
>          {28.71,94.61,91.93},
>   {44.67,99.18,69.12},
>   {45.43,16.94,17.89},
>   {48.21,69.92,14.9},
>   {56.23,58.24,56.29},
>   {56.27,8.56,49.27},
>   {60.21,56.49,36.16},
>   {61.37,96.74,40.58},
>   {71.25,36.42,3.29},
>   {76.02,23.65,1.45},
>   {81.59,8.05,17.58},
>   {85.03,23.5,88.75},
>   {97.87,3.39,80.46}};
> 
> I have tried:
> 
> In[2]:=Interpolation[d]
> 
> Interpolation:: indim :
>     The coordinates {3.53, <<3>>,<<20>>}  in dimension 1
>  are not consistent with other coordinates in this dimension.
> 
> Out[2]=Interpolation[
> {{3.53,35.01,58.66},{9.15,40.39,6.17},{12.52,94.88,86.27},
> {16.71,51.29,6.52},{16.88,24.18,46.21},{24.9,11.37,93.38},{25.28,56.62,
> 80.69},{28.71,94.61,91.93},{44.67,99.18,69.12},{45.43,16.94,17.89},{
> 48.21,69.92,14.9},{56.23,58.24,56.29},{56.27,8.56,49.27},{60.21,56.49,
>
36.16},{61.37,96.74,40.58},{71.25,36.42,3.29},{76.02,23.65,1.45},{81.59,8.05
,17.58},{85.03,23.5,88.75},{97.87,3.39,80.46}}]
> 
> 
> 
> ************
> Could someone please explain what the message
> ( The coordinates {3.53, <<3>>,<<20>>}  in dimension 1
>  are not consistent with other coordinates in this dimension.)
> means?
> In what sense  the  coordinates {3.53,...}   in dimension 1
> are not consistent with other coordinates. What do the signs
> <<3>>,<<20>> mean?
> Does the message message mean that some conditions required to do the
> approximation in the way mathematica tries, are not fulfilled?
> 
> 
> ***********
> 
> I have also try:
> 
> In[3]:=ListInterpolation[d]
> 
> ListInterpolationpol:: inhr :
> Requested order is too high;
> order has been reduced to {3,2}.
> 
> Out[3]=InterpolatingFunction[{{1.,20.},{1.,3.}},<>]
> 
> 
> What is the better (best) way to approximate the above data with
> *smooth*
> surface (using mathematica3.0 )?
> 
> Jan
> 
> 
> 


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