function F = mysuperpf(t,vec)
% Defines dr/dt = epsilon and f(x,r) = dx/dt for a function 
% exhibiting a supercritical pitchfork bifurcation
global epsilon

 r = vec(1);
 x = vec(2);
 
% Define the vector field 
 F(1) = epsilon;
 F(2) = -x+r*tanh(x);
 F = F';
