🚀 go-pugleaf

This may not be the ultimate newsgroup for this request, but:

We have been using the NLIN procedure in the SAS statistical analysis package
for magnetic multipolar expansion regression for some time now. To be more
specific, we use the "DUD" (doesn't use derivatives) multivariate secant method
by Ralston & Jennrich.
Now, we would like to move the crunching to a C program. Can anyone point me to
a source of C or C++ code for nonlinear regression, preferentially along the
DUD lines? For various reasons, PC/SAS is not an option in this case.

Thanks in advance,
-- 
   Per Hogstedt               Internet:  hogstedt@plab.se
   Lindholmen Utveckling            or:  hogstedt@ae.chalmers.se
   P.O. Box 8714              Phone...:  +46 31 50 70 50
   S-402 75 Gothenburg        Fax.....:  +46 31 51 53 13
   Sweden                     MiniCall:  +46 74 35 68 49