


 y = triangl(p, x, [y]) : Triangular
   iFunc/triangl Triangular fitting function
     y=(p(3)-sign(x-p(2)).*(x-p(2)))/p(3)^2;
     and y is set to the background outside the full width.
 triangl(width)          creates a model with a specified width
 triangl([ parameters ]) creates a model with specified model parameters
 input:  p: Triangular model parameters (double)
            p = [ Amplitude Centre HalfWidth 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=triangl([1 0 1 1], -10:10); or plot(triangl);
 Version: Nov. 26, 2018
 See also iFunc, iFunc/fits, iFunc/plot, heavisde, tophat
 (c) E.Farhi, ILL. License: EUPL.