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Spatial statistics and NonlinearRegress

• To: mathgroup at smc.vnet.net
• Subject: [mg13873] Spatial statistics and NonlinearRegress
• From: Ed Luschei <eluschei at montana.edu>
• Date: Wed, 2 Sep 1998 01:31:06 -0400
• Sender: owner-wri-mathgroup at wolfram.com

Hello,

(1) Has anyone out there done any MM work in spatial statistics? I'm
specifically interested in kriging.

(2) Is there a way to fit a piecewise function with NonlinearRegress?

e.g.

f[x_,a_,b_,c_]:=a + b(1-Exp[-x/c]) /; x<c; f[x_,a_,b_,c_]:=a +
b(1-Exp[-1]) /; x>=c;
data=Table[{i,f[i,0.2,5,25]+Random[Real,{-0.1,0.1}]},{i,30}];
NonlinearRegress[data,f[x,a,b,c],{x},{a,b,c}];

Doesn't seem to work because the df/dx doesn't exist at x=c.

Thanks!!
Ed (eluschei at montana.edu)