xt+1=xt+rxt(1-xt/K)-P xt2/(1+xt2)

This model describes the situation of the existence of predator. The P value is the degree of predators' eating or killing speed. The term of xt2/(1+xt2) means that if there are too many foods for the predator, the killed population per total population will get smaller because of the food saturation. In this Model, the population of predator is assumed to be constant.


r : Intrinsic Rate of Natural Increace

P : Killed Rate

K : Carrying Capacity

x0 : Initial Population

Simulation Time