Curve fit fails with exponential but zunzun gets it right

Question

I\'m trying to compute the best fit of two forms of an exponential to some x, y data (the data file can be downloaded from here)

Here\'s the code:

Answer 1

Zunzun.com uses the Differential Evolution genetic algorithm (DE) to find initial parameter estimates which are then passed to the Levenberg-Marquardt solver in scipy. DE is not actually used as a global optimizer per se, but rather as an "initial parameter guesser".

You can find links to the BSD-licensed Python source code for the zunzun.com fitter at the bottom of any of the site's web pages - it has many comprehensive examples - so there is no immediate need to code it yourself. Let me know if you have any questions and I'll do my best to help.

James Phillips zunzun@zunzun.com