Sudden zero population

[jkraska]

I'm fiddling around with various mods, and have mutated the growth scale only a little (4% versus 2% if I remember right).

In an experiment I'm running, population of a capital province one turn goes from somewhere in the 300,000's to *0*.

I can find no explanation for this at all.

Tax is 90.

There is no disorder.

There is no death scale, and no enemy candles.

There is no blood hunting in this province.

Any explanation?

[NTJedi]

One of the mods you installed is probably conflicting or breaking with another mod you installed.
Thus creating the mass genocide mod.

[Boron]

is there perhaps a limit to population ? that maximum is e.g. 0,5 mio and after that you get weird results ?

i remember some old games where 2 billion money was a border and when you had more you got suddenly 0 money . e.g. earth 2025

[Taqwus]

It's a wild shot in the dark, but this might occur if they're using integer arithmetic to update populations and an overflow happens.
e.g. instead of

x += x * (pop_growth/1000.0) with floating-point arithmetic, using
x += (x * pop_growth) / 1000 with integer arithmetic.
If x*pop_growth or similar expression exceeds approximately 4.2 billion (unsigned 32-bit integer) or 2.1 billion (signed 32-bit integer) weirdness could happen... although landing at exactly zero is strange unless there's a follow-up check that sets x to 0 if it were otherwise negative.

[Jack Simth]

As far as I can tell poking around in the ftherlnd files, province population is actually a signed 16-bit integer; but an extra 0 is appended at the end whenever the population is displayed - thus that 300,000 pop province had it's populaiton stored as 30,000 - a 4% increase would mean it goes up by 1200, putting it at 31,200 (stored) - not an immediate problem, if the 300,000 population figure was exact. However, if the population was much over 315,060 (31,506, stored) then that extra 4% pushes it above 327,670 (32,767, stored), which is the absolute limit that a 16-bit signed integer will hold. Beyond that it's overflow. Note that after you reached 300,000 population, it would only take 2-3 turns at 4% growth to have the same problem.

[NTJedi]

I recall the population limit for any province is 50,000.

[Boron]

Originally posted by NTJedi:
I recall the population limit for any province is 50,000.

i remember having a population of 70k or so in a long sp game in my capitol .
most likely you remember that from mapediting :
#population [0-50000] stands in the mapedit.pdf as command for population

[ July 07, 2004, 17:29: Message edited by: Boron ]