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)