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Details of fuel consumption and AR pop decay Sat, 06 January 2018 13:54 Go to next message
mrvan is currently offline mrvan

 
Chief Warrant Officer 2

Messages: 156
Registered: May 2014
I was playing a bit with fuel consumption and AR in-flight pop decay and somehow couldn't quite match the numbers I see in-game.

Assuming the following formula (from the wiki):
- fuel = weight/200 * distance * efficiency * (0.85 if IFE else 1)

It turns out I needed to make the following extra assumptions to make it work:
- distance is rounded UP (e.g. 79.1 -> 80)
- fractional distances larger than warp^2 are rounded DOWN (e.g. 81.54 -> 81)
- consumption per turn is rounded UP
- AR pop death happens BEFORE fuel consumption*, but the interface doesn't know this

Example 1: taking 2 medium freighters with fuel mizer and 420 pop 41.44 ly, real consumption is 171, but interface 'estimates' at 175.

Assuming weight = 138 + 420 - 12 (losses) = 408 and fuel efficiency 1.75 (warp 7 mizer)

ceil((138+420-12) / 200 * ceil(41.44) * 1.75 * 0.85) = 171

The interface seems to calculate without losses:

ceil((138+420) / 200 * ceil(41.44) * 1.75 * 0.85) = 175

Example 2: Taking the same fleet 64.56 ly actually consumes 350 fuel:

ceil((138+420-12) / 200 * floor(64.56) * 2.35 * 0.85) = 350

interface predicts 364, which seems to miss both rounding down 64.6 and the losses:

ceil((138+420) / 200 * ceil(64.56) * 2.35 * 0.85) = 364

It means that the interface fuel estimate cannot be trusted even for single year jumps for AR, which was new to me at least.

Not sure of all of this is known, and it might not be 100% correct, but this seems to make the formula match real world results on my test cases.

About AR pop death, it's obviously 3% rather than the 2% mentioned here [ https://wiki.starsautohost.org/wiki/AR_Guide_by_Leonard_Dick ens_-_Revised:_21st_September_2000]. However, I still don't quite understand why at 2200 colonists you don't lose one (22*.03=.66, 23*.03=.69), how is that rounded?

*) so it's not the warp itself that kills AR, but really their fear of the warp, a bit like in the I, Robot story -- although that doesn't explain why a stalled cheap engine doesn't kill...


[Updated on: Sat, 06 January 2018 13:54]

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Re: Details of fuel consumption and AR pop decay Tue, 16 January 2018 08:19 Go to previous messageGo to next message
XAPBob is currently offline XAPBob

 
Lt. Commander

Messages: 907
Registered: August 2012
Does that work for IS as well (i.e. pop change before fuel consumption calculated)?

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Re: Details of fuel consumption and AR pop decay Sun, 15 April 2018 18:38 Go to previous messageGo to next message
m.a@stars is currently offline m.a@stars

 
Commander

Messages: 2745
Registered: October 2004
Location: Third star to the left
mrvan wrote on Sat, 06 January 2018 19:54
Assuming the following formula (from the wiki):
- fuel = weight/200 * distance * efficiency * (0.85 if IFE else 1)

It turns out I needed to make the following extra assumptions to make it work:
- distance is rounded UP (e.g. 79.1 -> 80)
- fractional distances larger than warp^2 are rounded DOWN (e.g. 81.54 -> 81)
- consumption per turn is rounded UP

Seems to fit what I found years ago for the Fuel Usage Tool Very Happy



So many Stars, so few Missiles!

In space no one can hear you scheme! Deal

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Re: Details of fuel consumption and AR pop decay Mon, 16 April 2018 17:32 Go to previous messageGo to next message
mrvan is currently offline mrvan

 
Chief Warrant Officer 2

Messages: 156
Registered: May 2014
So.. someone should edit the wiki? Smile

Frankly, I wasn't expecting anything about stars to be novel after ~30 years, it's just that experience didn't match the wiki, so I thought to report it.

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Re: Details of fuel consumption and AR pop decay Tue, 17 April 2018 18:40 Go to previous messageGo to next message
m.a@stars is currently offline m.a@stars

 
Commander

Messages: 2745
Registered: October 2004
Location: Third star to the left
Wikis are for editing. Rolling Eyes

Here's my original post, should you want to compare details.



So many Stars, so few Missiles!

In space no one can hear you scheme! Deal

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Re: Details of fuel consumption and AR pop decay Wed, 18 April 2018 14:18 Go to previous message
craebild is currently offline craebild

 
Lieutenant

Messages: 558
Registered: December 2003
Location: Copenhagen, Denmark
m.a@stars wrote on Wed, 18 April 2018 00:40
Wikis are for editing. Rolling Eyes

Here's my original post, should you want to compare details.

The URL for the fuel calculator you list in that thread does not exist any longer, the correct URL is now http://craebild.dk/hab_range_tool/fuelusage.html



Med venlig hilsen / Best regards / Mit freundlichen Grüßen
Christian Ræbild / Christian Raebild

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