y = sigmoid(p, x, [y]) : Sigmoidal
iFunc/sigmoid Sigmoidal S-shaped
y = A0+(A1-A0)./(1+exp(-(x-x0)/w))
This is a sigmoid S-shaped curve, aka logistic.
sigmoid(threshold) creates a model with specified threshold
sigmoid([ parameters ]) creates a model with specified model parameters
Ref: http://en.wikipedia.org/wiki/Sigmoid_function
input: p: Sigmoidal model parameters (double)
p = [ Amplitude Center Width BackGround ]
or action e.g. 'identify', 'guess', 'plot' (char)
x: axis (double)
y: when values are given, a guess of the parameters is performed (double)
output: y: model value or information structure (guess, identify)
ex: y=sigmoid([1 0 1 1], -10:10); or plot(sigmoid);
Version: Aug. 22, 2017
See also iFunc, iFunc/fits, iFunc/plot, doseresp
(c) E.Farhi, ILL. License: EUPL.