I have been using the genfit function in Mathcad for some non-linear curve fit and it works perfectly well. However, I would like to implement the same in C++. Can anyone tell me how I go about it? I tried an open source C++ version of the genfit (Levenberg-Marquardt method) algorithm but the results were'nt as good as what I got in mathcad.I would really appreciate if some one could point me towards an exact implementation of the mathcad genfit algorithm in C++. Thanks in advance for the help.
Thanks a lot Richard for your quick reply, What I meant by poor results was the fit wasnt anywhere as good as what I got with Mathcad. But i found out the problem. The target integration error was set to a very low value which resulted in a very poor fit:). Its working fine now. Thanks for the link to the NR website as well.