[1.9.5.5] Double Population Growth Bug

[Icemania]

From various test games "planet type X colony growth rate doubled" as per various Colonisation technologies does not appear to work. My experience is that this is a general problem and isn't specific to particular circumstances.

[Tcby]

I wonder if this changed with universe.

Last time I checked this (shadows,december) a bonus was applied, but a strangely small one. Test planet was high quality Ikkuro colony with advanced medicomplex and <500 mil pop, with plenty of resources. The displayed growth rate was very high due to the stacked bonuses from low pop / 0 tax (pre universe 0% growth rates )/ medicomplex. The growth rate went from 60-something to only slightly more...the +100% growth from wonder and low pop did not interact with the colonisation tree bonuses.

Basically I expected this:
New base rate 32 (Ikkuro 16x2 from tech) + 100% (32) + 100% (32) = Pop growth 96

...but I believe the result was:
New base rate = 32, + 100% (of old base, 16) + 100% (of old base, 16) = 64

Anyway I guess that's unimportant if it isn't working at all at present.

[Icemania]

There has been no response to this bug since it was reported on July 18th. Please advise.

[UnfriendlyBG]

I think this is an important issue that should be looked at. If it is indeed broken it makes 5 expensive techs in the AI mod completely useless (aside from terraforming). I'm not familiar with the vanilla tech tree off hand but its making at least 1 tech there completely useless as well.

[Osito]

I did some extensive testing to try to replicate this bug, using the default theme and the AI theme. You will perhaps find point (4) the most interesting. In particular I tried these tests:

(1) I checked pop growth rates on homeworlds of various planet types, then added the double population growth tech. Result: no discernable effect on population growth rate over the following game year.

(2) I used the editor to colonise a native planet (of various types) with 4 billion pop, and looked at the population growth rate. I then used the editor to add the double population growth tech, then added a colony of 4 billion pop. Result: no discernable effect on population growth rate over the following game year.

(3) I used a colony ship to colonise a colony of my native planet type both with and without the double population growth tech. Result: no discernable effect on population growth rate over the following game year.

(4) I used a colony ship to colonise a colony of non-native planet type both with and without the double population growth tech. With the growth rate tech, the population had double the population growth rate. I got the same result with different races and different non-native planet types. I repeated test (2), but for a non native planet type, and I again got the double population. I retested with the AI improvement mod and got the double population.

Conclusion:

I'm not sure whether the double population tech is working as intended: it is clearly not doing clearly not doing exactly what it says on the tin, but it is doing something. Specifically, it appears that this tech only works for an empire's non-native planet types. I'm not sure what would happen if you used an alien population to colonise a planet type which was non-native to them, but native for the original empire.

I also found that you can more than double the growth rate at non-native planets, but since the growth rate at native planets can't be increased by this tech, it doesn't seem realistic to push it above double.

I'd be interested to know whether anyone else gets the same results.

Osito

[Icemania]

I greatly appreciate that Osito, certainly helps narrow down the bug. I did some further tinkering and the results were consistent with your observations. Hopefully Elliot can use that to resolve the problem.

[elliotg]

Thanks for the report and research on this one.

After a careful look at this myself I can report that this is actually working, with the exception that the growth rate for the native planet type of a race is unaffected. This is all working as designed.

So to put it another way: the population growth rate for a race's native planet type is always at full speed, but other planet types for the race are normally at 50% speed. But once you research the relevant colonization tech, the growth rate for that non-native planet type is then doubled to 100%.

Remember that many other factors also feed into population growth rates: quality of planet, resources available, bonuses from race/ruins/facilities, government type, etc. But the double growth rate ability is working properly on top of these other factors.

Thanks
Elliot