iFit/expstretched

 y = expstretched(p, x, [y]) : Exponential decay

   iFunc/expstretched Stretched exponential decay fitting function
     Tau is the expeonential decay parameter, in inverse 'x' units.
     y=p(4)+p(1)*exp(-(x/p(2)).^p(3));

 expstretched(decay)          creates a model with specified decay constant
 expstretched([ parameters ]) creates a model with specified model parameters

 input:  p: Stretched exponential decay model parameters (double)
            p = [ Amplitude Tau Exponent BackGround ]
          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=expstretched([1 0 1 1], -10:10); or plot(expstretched)

         I will not buy this exponential; it is stretched.
         <http://en.wikipedia.org/wiki/Dirty_Hungarian_Phrasebook>

 Version: Aug. 22, 2017
 See also iData, iFunc/fits, iFunc/plot
 (c) E.Farhi, ILL. License: EUPL.