Duffing Attractor

The Duffing attractor is a 2-dimensional strange attractor produced by the following equation:

x_{n + 1} = x_{n} + y_{n} dt

y_{n + 1} = y_{n} + g cos (w dt) - d y_{n} + a x_{n} - b x_{n}^{3}

a = linear stiffness
b = amount of nonlinearity in the restoring force
d = damping
g = amplitude of the driving force (0 if no driving force)
e = angular frequency of the periodic driving force

Duffing attractor