World Simulation Update 25-May-2007

Completed two simulations this past week. I made some changes to the rabbit model as a result of the simulation.

The population didn't peak until 114,000. Not too odd, I really didn't know expect what to expect for the population peak. The collapse leveled out at 40k rabbits. Too many rabbits, unless it was a giant rabbit farm. I adjusted how much a rabbit ate every day. Each increase gave diminishing returns on how much the population dropped. I ended with the rabbits consuming 5 times more than what it was before. This reduced the population by 4 times. The rabbit population averaged about 10k or roughly 1 rabbit per cell Other changes that I made resulted in only small drops that would eventually increase to 10k over time. It just left a higher vitality rate. Still high, but then there isn't any competition for food. I threw in 20 predators at the end and then 40. No changes in the average population, just changes in the wavelength of the population waves.

The second simulation ran faster. I left the rabbit feeding rate unchanged from what I raised it to in the first simulation. The population peak was only 40k this time. I slowly implemented the number of predators into the simulation. First 40 day, then 80, then 120. As you can see the wavelength of the population increases with more predators in the system. apparently 120 predators hit a crossover point. Vitality started going up population growth was barely positive. Vitality growth was not faster than pop growth though. This eventually led to another collapse. This time the collapse left the rabbit population at a level where it couldn't support the predators population.

The predators are very simple they eat 1 rabbit every day. I still need to work on the animal objects and do the coding for the fox so that it is tied down to a cell and can only see so much of the world around him.

I think I'm going to increase the world size from 1 sq km to 10 sq km. That translates to over 1 mil cells. It should be large enough so that when I start to add larger herbavoirs, they will be supported in large enough populations.