Author Topic: Population not actually growing by the listed growth%?  (Read 3494 times)

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Offline Kyle (OP)

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Population not actually growing by the listed growth%?
« on: September 08, 2018, 12:10:31 PM »
So on a fresh game, Earth starts out at 500 pops and a growth rate of 2.52%

But if I increment 5 days, the population jumps to 500.200

Even though 500 pops * (1 + 0.0252 growthRate * 5 days / 360 daysPerYear) = 500.175   / For pasting into calculator: 500 * (1 + 0.0252 * 5 / 360) 

What's interesting is that if I pretend there are 315 days in a year, it comes out to a perfect 500.200!

"Compounding interest" is not the answer, that doesn't even get it close to 500.200.

Further, if I increment 5 days 6 times, the population lands at 501.200, but if I increment by 30 days 1 time, the population lands at 501.050, even if I force sub pulses to be 1 or 5 days.

Before I write these off as just a quirk/bug to take into account, is there any other explanation, particularly for why the pop grows faster than it should?
 

Offline Havear

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Re: Population not actually growing by the listed growth%?
« Reply #1 on: September 08, 2018, 01:03:44 PM »
I'd like to add, real quick, that the default big tick time is only "approximately" five days at 400,000 seconds, which is likely a pretty fair chunk of time shaved off. Additionally, Aurora models a year as 12 months of 30 days of 24 hours, rather than using a more accurate calendar.
 

Offline QuakeIV

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Re: Population not actually growing by the listed growth%?
« Reply #2 on: September 08, 2018, 01:53:24 PM »
Regarding the calendar thing, Steve is using a time library from C# for the new version, so it will display years exactly as we have them in the real world.
« Last Edit: September 08, 2018, 03:23:29 PM by QuakeIV »
 

Offline Kyle (OP)

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Re: Population not actually growing by the listed growth%?
« Reply #3 on: September 08, 2018, 02:24:36 PM »
500 pops * (1 + 0.0252 growthRate * 5 days / 360 daysPerYear) = 500.175

This already factors in a 360 day year.  And using 400000 seconds rather than 432000 seconds (5 days) would make the actual growth that occurs even more wrong.

Also if you take a custom turn of 424800 seconds, you get 0.15m people, but if you take 424801 seconds instead, you get 0.20m people.

669601 = 0.3 growth
669600 = 0.25 growth
540001 = 0.25 growth
540000 = 0.2 growth
424801 = 0.2 growth
424800 = 0.15 growth

Yeah gonna go with bug :)
« Last Edit: September 08, 2018, 05:20:01 PM by Kyle »
 

Offline Father Tim

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Re: Population not actually growing by the listed growth%?
« Reply #4 on: October 09, 2018, 01:22:57 PM »
The growth shown is based on the actual amount of seconds that have passed since the last construction phase.  So if you have it still set at the default "5 days" -- which, as noted above, is not precisely five days -- and you, for example, advance time by 1 day four times, then by 8 hours, then 3 hours, then 5 days, the actual pop growth will be for ~9.5 days and not ~5 days.

So five days, plus a few hours for a battle, plus another five days would generate the behaviour you have noticed for pop growth.

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