When implementing the Lotka-Volterra model using one Compartment block (one for both the predator and prey), the compartment needs to be vectorized. I.e. the rabbit and fox species needs to be added as modelled materials or created as indexes from Index-list. Then either one can use the same approach as in the two Compartment solution, using Source/Sink and Transfer blocks as means to model the dynamic behaviour or just explicitly define the differential equation inside the Compartment.

Equations for Transfers:

• AnimalBirth[Rabbits]=Animals·a
• AnimalBirth[Foxes]=Animals[Rabbits]·Animals[Foxes]·e·b
• AnimalDeath[Rabbits]=b·Animals[Rabbits]·Animals[Foxes]
• AnimalDeath[Foxes]=c·Animals

Initial Conditions for compartment:

• For Animals[Rabbits] = Init_population
• For Animals[Foxes] = Init_population

Values for parameter Initial population:

• Init_population[Rabbits]= 1000
• Init_population[Foxes]= 4

Figure 1 Ecolego matrix of one Compartment approach

Solution to the excersise

• lotka-volterra.eco

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References

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