%
%   SF_DEMO_EQN.M   Function file for SF_DEMO1.M & SF_DEMO2.M  -->  y' = sin(x-y)
%
%   This file simply evaluates yp = f(x,y) for the input x and y values.  This is
%   called as part of a demo for plotting slope fields with SFIELD.M and drawing the
%   solution curves with ODE23.M.
%
%   NOTE:  Since this file will be called with x and y as matrix arguments, be sure to
%   use element-by-element arithmetic (i.e. "dot arithmetic"), as needed, for definng
%   the RHS function, f(x,y).
%
%   File prepared by J. R. White, UMass-Lowell (Feb. 2007)
%
      function yp = sf_demo_eqn(x,y)
      yp = sin(x-y);
%
%   end of function
