iFit/quadline

 y = quadline(p, x, [y]) : Quadratic line

   iFunc/quadline Quadratic fitting function
     y=p(3)+p(2)*x+p(1)*x.*x;

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

 input:  p: Quadratic line model parameters (double)
            p = [ Quadratic Linear Constant ]
          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=quadline([1 0 1], -10:10); or y=quadline('identify') or p=quadline('guess',x,y);

 Version: Aug. 22, 2017
 See also iFunc, iFunc/fits, iFunc/plot, strline, quad2d
 (c) E.Farhi, ILL. License: EUPL.