*To*: mathgroup@smc.vnet.net*Subject*: [mg10707] Re: Duplicate Elements in List cause Errors with Interpolation*From*: Paul Abbott <paul@physics.uwa.edu.au>*Date*: Fri, 30 Jan 1998 04:24:42 -0500*Organization*: University of Western Australia*References*: <6ahp25$pkv@smc.vnet.net>

Todd Rose wrote: > This doesn't seem to work for me. I can't figure out how to remove the > duplicate in the first element of the data pairs (0.4375). Union only > seems to work if they are alike in both the abscissa and the ordinate. > Perhaps I can use a test with the Union command, but I have not been > able to figure out the format for the "spec". In[2]:= mydata = Union[mydata, SameTest -> (First[#1] == First[#2] & )]; removes duplicate first elements. In[3]:= lp = ListPlot[mydata]; In[4]:= myfunction = Interpolation[%, InterpolationOrder -> 1]; However, for this dataset, why use Interpolation anyway? I think a Fit is a much better idea: In[5]:= fit[x_] = Fit[mydata, {1, Sqrt[x], x}, x] Out[5]= -17.9046 x + 116.859 Sqrt[x] - 13.4646 In[6]:=Plot[fit[x], {x, 0, 5.3}]; In[7]:= Show[%, lp]; Cheers, Paul ____________________________________________________________________ Paul Abbott Phone: +61-8-9380-2734 Department of Physics Fax: +61-8-9380-1014 The University of Western Australia Nedlands WA 6907 mailto:paul@physics.uwa.edu.au AUSTRALIA http://www.pd.uwa.edu.au/~paul God IS a weakly left-handed dice player ____________________________________________________________________