The equations for ExpGauss and ExpConvExp

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Hi there,

Does anyone know what's the explicit equations for the fitting function ExpGauss and ExpConvExp used in Igor Pro?

Thanks
garrison wrote:
Hi there,

Does anyone know what's the explicit equations for the fitting function ExpGauss and ExpConvExp used in Igor Pro?

Thanks


Well, ExpGauss (or ExpModGauss in Multi-peak Fit 2) is a convolution of a gaussian peak with an exponential. But it turns out it can be reduced to an analytic expression. You can see the expression as implemented in an Igor function: Pull down the Windows menu and select Procedure Windows->Peak Functions.ipf. The function you need to look at is fExpGauss(). Then the actual fitting function scales that expression as in fExpGaussFit().

The same is true of ExpConvExp, but that is the convolution of an exponential with another exponential. The expression used in implemented in the same procedure window, in the function fExpConvExp(). The scaled fitting function is in fExpConvExpFit(). There are some comments in the procedure window that may help understanding these functions.

Note- if you are using Igor 5, the procedure windows are listed under Other Windows in the Windows menu.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com

November 12, 2008 at 09:58 am - Permalink