Code covered by the BSD License  

Highlights from
Interactive Peak Fitter, version 2.2

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from Interactive Peak Fitter, version 2.2 by Tom O'Haver
A peak fitting program for time-series signals.

(2.*n)./(1+n);
function g = logistic(x,pos,wid)
% logistic function.  pos=position; wid=half-width (both scalar)
% logistic(x,pos,wid), where x may be scalar, vector, or matrix
% pos=position; wid=half-width (both scalar)
% T. C. O'Haver, 1991 
n = exp(-((x-pos)/(.477.*wid)) .^2);
g = (2.*n)./(1+n);

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