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Non-linear Curve Fitting

• To: mathgroup at yoda.physics.unc.edu
• Subject: Non-linear Curve Fitting
• From: David Elbert <ELBERT at midd.bitnet>
• Date: Wed, 22 Apr 1992 17:43 EST

Folks-
I have had great success using the Mma "Fit[]" routine.  I was recently
asked, however, if I could fit some data pairs to an expression like:
y=a(Tanh[b x]}
This involves fitting nonlinear coefficients and isn't documented in the
BIG BOOK.  Is there, in fact, a way to fit to this "b" parameter.
It seems that it is a much harder problem than simple fits and
would require an iterative approach.  Perhaps it isn't possible
with the built-ins and someone else has a package
available?  I've been told that it is easy in the math
and plotting package known as "Igor" on the Mac...isn't that
enough of a gauntlet to make someone want to
show me how to do this??
Thanks-
David Elbert
Dept. of Geology
Middlebury College
MIddlebury , VT 05753
(802)388 3711 x5652

Elbert at midd.bitnet