Simulation Lab

A grid world of plants, herbivores and predators, from the Python ABM lab. Plants regrow on free cells, herbivores graze, predators hunt, every move costs energy, and creatures that store enough energy reproduce with mutated speed and vision, so those traits evolve under selection. Optuna searched for lasting coexistence: all three species survive, stay clear of extinction and keep bounded, balanced numbers. The browser Predator – Prey sheet shows the same cycle as two differential equations.

Engine

Mesa 3.5 · MultiGrid

World

50 × 50 torus · 300 plants, 80 herbivores, 50 predators at start

Key parameters

plant regrowth 0.026 · mutation rate 0.05 · reproduction at 22.3 energy

Run

1000 steps · seed 34600

Tuning

Optuna, 500 trials · winner #346

Score

0.7341 of 1 (coexistence, stability, balance)

Colours

green cells = plants · white = herbivores · orange = predators