Re: Mathematica question
- To: mathgroup at smc.vnet.net
- Subject: [mg8134] Re: [mg8111] Mathematica question
- From: seanross at worldnet.att.net
- Date: Fri, 15 Aug 1997 23:41:46 -0400
- Sender: owner-wri-mathgroup at wolfram.com
MEINERSH at CV3.CHEM.PURDUE.EDU wrote: > > Hello, > I am a beginner Mathematica user and am having a bit of trouble with a > curve fit. I'm sorry to bother you, but when I try to get into the > archives our computer doesn't seem to like it. > I am trying to fit a fluorescence lifetime decay that is at least a > double exponential. I am really confused when following the curve fit > section of the manuel and have tried a few things but with no success. I > would appreciate if you could give me a few hints or insight to curve > fitting. > Thank you for your time, > Julia Meinershagen It is hard to know how to respond since your question is a little vague. The built-in function "Fit" is really only designed to fit things to algebraic series. They do give an example in the Mathematica book about taking the Log of the function, then fitting and taking the exponential, but this is a rather tortuous way to fit functions. I recommend looking in the NonlinearFit add-on package. This function allows you to choose an arbitrary basis set of functions. If you are using Mma 3.0, look it up in the Add-on Packages section of the on-line help. If you are using 2.2, I recommend buying a copy of the 2.2 guide to standard add-on packages. In either case, <<Statistics`NonlinearFit` will load the package for you.