function d=fish(t,y)
% fish(t,Y) provides the right side of the system
%           x'=y; y'=a*y+x-x^2.
% where Y=[x,y] nd a=parameter (global).  See Hale & Kocak Example 7.27.

global parameter 
d=[y(2);y(1)*(1-y(1))+parameter*y(2)];
% M. Day, June 4, 2005
