I've started work on a fairly complex economic simulation (prototyping for eventual inclusion into a game) and I'm trying to add features slowly and one at a time. The turn-based simulation will have people, jobs, businesses, buildings, etc. Right now, though, I'm stuck with how to deal with competing gameplay mechanisms. The land has a certain "sustainable limit" of resources, which is the max amount that can be harvested per turn without damage. People have a per-turn resource requirement, like 2 food and 2 water. At the beginning of each turn, every person attempts to collect the resources vital for their survival. Now, the problem comes when there are twenty people living with enough sustainable resources for fifteen. There are two mechanisms I want to have to deal with this. One is if a person doesn't get their resources, they die. Two is when, say, 20 units of water are harvested from a source that only provides 15, the difference is subracted from the capacity, so the capacity is only 10. The first one is pretty obviously needed in some form. The second one keeps people from continually abusing the resources while still being flexible. I plan to have the resources eventually recover from abuse. However, in programming this, my people either stop gathering when they reach the limit and those yet to harvest die (which I really don't like), or they eventually exhaust the food source and then all die. Any suggestions to moderate these two approaches so both get used well? I'm having brain blockage.

I think some resources should be maintainable, within constraints. This is basically why crop rotation came about - persistently farming the same crop produced declining yields.

Expanding populations will generally require expanding territory, or the excess die. Are your populations making moves to expand territory yet?

I managed to think up a solution that seems to produce some good results, and I've spent today implementing it and playing around with it.

First of all:
@Anonymous Poster: Doesn't seem like a bad idea, but hopefully my idea will work as well.

@_winterdyne_:The land's "sustainable limit" is really the how much it will take before it degenerates from basic gathering, like people just wandering around picking berries and grasses. Eventually, people will be able to build farms and such. These will gather food up to the sustainable limit, but will be able to boost their output with improvement. So they will gather in 20 food, but put out 30, simulating the improvement of land. But that's in the future. Oh, and right now, the whole thing takes place on one "piece" of land. I'm presuming it to be village size.

On to my solution:

People now can be Healthy, Sick, or Dead. If they're dead, they're moved off to the unused persons list and not touched. Healthy consumes standard resources and will have full production points. Sick consumes half resources but has limited or no production points. People still die immediately if they can't get resources. But if they have to rely on excess, they become sick. This lowers their requirements, and semi-stems the wave of death that used to follow overpopulation. If everyone is sick, and they still have to take from excess, those who take from excess die. I also added a heal rate (will be modifiable by buildings, and there will be other causes of sickness) so that people can become unsick.

After playing with it, I noticed some interesting things, besides some tricky bugs I'm still fighting with. After adding one person to a full population, nearly a third perish after a couple years (four turns to a year) of "famine." Also I've noticed an interesting case where things don't re-generate at the right rate, so one person survives and flips between sick and healthy. Heal rate also plays a big factor, as it only waits to heal until no more people are getting sick, not until the resources have regenerated. So people heal too fast and doom the recovery if the rate is above 25%. I'm going to work some more on these bugs.

Update: Fixed a bug that ironically, made everything work well. So I tweaked it to only subtract half the excess from the capacity. Interestingly, at small values of the resource requirement, the population follows a straight line to destruction. But at higher values, things stabilize with only a few losses. As stated above, losses increase as the heal rate increases. I guess my people will make sure to kill the doctors first in case of a famine.

[Edited by - Texas Brigade on August 20, 2006 11:50:33 PM]