iFit/gauss1

 y = gauss1(p, x, [y]) : Gaussian without background

   iFunc/gauss1 Gaussian fitting function without background
     sigma = p(3)/(2*sqrt(2*log(2)))=p(3)/2.3548
     y = p(1)/(sigma*sqrt(2*pi))*exp(-0.5*((x-p(2))/sigma).^2);

     The Amplitude is:       p(1)/(p(3)/(2*sqrt(2*log(2)))*sqrt(2*pi))

 gauss1(width)          creates a model with a specified width
 gauss1([ parameters ]) creates a model with specified model parameters

 Reference: http://en.wikipedia.org/wiki/Gaussian_function

 input:  p: Gaussian model parameters (double)
            p = [ Intensity Centre HalfWidth ]
          or 'guess'
         x: axis (double)
         y: when values are given and p='guess', a guess of the parameters is performed (double)
 output: y: model value
 ex:     y=gauss1([1 0 1], -10:10); or plot(gauss1)

 Version: Nov. 26, 2018
 See also iFunc, iFunc/fits, iFunc/plot, lorz, gauss
 (c) E.Farhi, ILL. License: EUPL.