Bifurcation diagram

The behavior of a system can vary greatly depending on the model parameters. A value of a model parameter at which the fixed points of the system suddenly change is called a bifurcation point.

A bifurcation diagram shows how an ODEs fixed points depend on the parameters to the system.

Consider for example the system x˙=f(x;h)\dot x = f(x;h) where f(x;h)=3xx2hf(x;h) = 3x-x^2-h. This ODE might be used to model, for example, the population of fish in a farm, where xx is the number of fish and hh is the harvesting rate. The fixed points at which f(x;h)=0f(x_*;h)=0 are

x±=12(3±94h). x_*^\pm = \frac{1}{2} (3 \pm \sqrt{9-4h}).

The bifurcation diagram below shows the fixed points as a function of hh.

The bifurcation point is at h=94h=\frac94, where there is only one fixed point.