fitting_Gamma function

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Thu, 02/11/2010 - 04:33 pm

I am new to Igor. I am trying to do gamma fitting for histogram.Advance thanks.
Please specify what kind of PROBLEM you are experiencing and trying to solve. Without these details, there's nothing much we can do for you.
Do you know about curve fitting in general? Do you want to know how to specify a Gamma function as a fit function? Etc. etc.

February 12, 2010 at 02:01 am - Permalink

harneit wrote:
Please specify what kind of PROBLEM you are experiencing and trying to solve. Without these details, there's nothing much we can do for you.
Do you know about curve fitting in general? Do you want to know how to specify a Gamma distribution as a fit function? Etc. etc.

I am using curve fitting, but gamma Probability density function is missing in the function list. I do not know how to call or let it appear in curving fitting option. (the name(function) of "Gamma" is already in Igor).Many thanks.

February 12, 2010 at 05:56 am - Permalink

Have you read the section about user-defined fitting functions? You can do so by executing displayHelpTopic "User-Defined Fitting Function: Detailed Description" on Igor's command line.
Your fit function might look similar to this:
Function GammaFit(w,x) : FitFunc
    WAVE w
    Variable x

    return w[0]+w[1]*gamma(w[2]*x+w[3])
End

February 12, 2010 at 06:42 am - Permalink