Homework 2: Predator-Prey Agents

In this lab you will continue working on your agent simulation. If you did not manage to finish the homework, do not worry, you can use this script which contains all the functionality we developed in the lab.

How to submit?

Put all your code (including your or the provided solution of lab 2) in a script named hw.jl. Zip only this file (not its parent folder) and upload it to BRUTE. Your file cannot contain any package dependencies. For example, having a using Plots in your code will cause the automatic evaluation to fail.

Counting Agents

To monitor the different populations in our world we need a function that counts each type of agent. For Animals we simply have to count how many of each type are currently in our World. In the case of Plants we will use the fraction of size(plant)/max_size(plant) as a measurement quantity.

Compulsory Homework (2 points)

  1. Implement a function agent_count that can be called on a single Agent and returns a number between $(0,1)$ (i.e. always 1 for animals; and size(plant)/max_size(plant) for plants).

  2. Add a method for a vector of agents Vector{<:Agent} which sums all agent counts.

  3. Add a method for a World which returns a dictionary that contains pairs of Symbols and the agent count like below:

julia> grass1 = Grass(1,5,5);
julia> agent_count(grass1)1.0
julia> grass2 = Grass(2,1,5);
julia> agent_count([grass1,grass2]) # one grass is fully grown; the other only 20% => 1.21.2
julia> sheep = Sheep(3,10.0,5.0,1.0,1.0);
julia> wolf  = Wolf(4,20.0,10.0,1.0,1.0);
julia> world = World([grass1, grass2, sheep, wolf]);
julia> agent_count(world)Dict{Symbol, Real} with 3 entries:
  :Wolf  => 1
  :Grass => 1.2
  :Sheep => 1

Hint: You can get the name of a type by using the nameof function:

julia> nameof(Grass):Grass

Use as much dispatch as you can! ;)