TL;DR: I ran an early game comparison (39 turns) in 1.90, and found AI still lags human player significantly (6-10x) in manufacturing or/and research at Genius difficulty. Technically, it is difficult for AI to minmax, but a (hopefully) simple return-on-investment look-up table for build orders should improve AI performance by 2x-3x. And it will greatly benefit AI performance in mid and late game.
Background: Long time Galciv2 and Galciv3 player. I have been really excited about Brad’s return to the AI development of Galciv3. Version 1.90 Opt-in has been a big step forward and reignite my interest in playing the game again.
Objective: Early game AI performance in colonization and colony building at genius level (moderate AI bonus)
Why early game? If AI lags significantly in production/research in early game, human player can soon snowball in grabbing planets and building large navy to steamroll AI players.
Game setup: Hugh galaxy, loose cluster: 1 human player (Arcean) + 8 AI players. Turn 1 and 39 saves are in the following dropbox zip file
Turn 1: C1.GC3Sav
Turn 39: C_Arcean_39.GC3Sav (Human Arcean, AI for the rest)
C_Yor_39.GC3Sav (Human Yor via “localplayer 2” at turn 1)
C_Thalan_39.GC3Sav (Human Thalan via “localplayer 4” at turn 1)
Three turn-39 saves are provided to find out how much human player can outperform AI: Yor is chosen for its unique play style of population assembly; Thalan is chosen for its strong starting tech, Hive.
Comparing C_Arcean_39.GC3Sav and C_Thalan_39.GC3Sav and focusing on Arcean development, we can see that AI underperforms human player by 10x in manufacturing, leading to slow colony ship/constructor production. This has results in fewer planets being colonized, slower research and underproduction in military ship as well.
AI Manu: 20; Research 24; Income: -2.4; Pop 11/11; Approval:79; influence: 70.4
Human Manu: 215.4; Research 21.2; Income: -6.6; Pop 16.6/21; Approval:62; influence: 82
Planet Matrix II (*U in human game)
AI Manu: 29.2; Research 12.5; Income: -1.2; Pop 2.5/4; Approval:100; Influence: 45
Human Manu: 302.5; Research 60.2; Income: -10.2; Pop 3/3; Approval:100; Influence: 56
What happened and how do we fix AI? Let’s compare the same games and do a return-on-investment analysis, for Thalan.
Thala under AI: Manu: 42; Research 31; Income: -0.2; Pop 9.5/13; Approval:100; influence: 82.3
Thala under Human:Manu: 105; Research 24.9; Income: -6.1; Pop 10.9/14; Approval:100; influence: 76.4
AI clearly is not building the right buildings. It current build order is Port of Call, with a cost of 135 Manu for 25%+ tourist income of 1.8 base = 0.45income. ROI: 0.33income/100 Manu
What are the alternatives?
Replacing the factory with a Manu Capital (red arrow): Cost: 227 Manu à Return: increase in Manu from 15%(base)+25%(received)+20%(giving) to (200%(base)+25%(received)+60%(giving). 225% increase in Manutotal
Other low-yield buildings
Market center: 30 manu à 0income (base is 0): ROI=0
Alternative: colonial hospital 30 manu -> 25% growth +5% (adjacency) + 2 food
This option is also much better than birthing subsidy (10%)
Research center (orange arrow): +15% research (base)
Alternative: built next to the two research center: +15%(base)+ %10(received)+10%(giving) = 35% research
Other major issues:
AI has not used any soil upgrade by Turn 39
AI has not researched or built Hive, which gives 4+ production
Similarly for Planet Eradys I (*$ in C_Thalan_39)
AI got Manu: 30; Research 12; Income: 0.1; Pop 2.7/4; Approval:100; influence: 53
Human got Manu: 38; Research 82; Income: -7.6; Pop 3/3; Approval:100; influence: 52.2
Let’s now look at Yor AI. Comparing C_Arcean_39.GC3Sav and C_Yor_39.GC3Sav, you can see Yor is also lagging significantly. The most productive colonies Iconia and Rose Morrin I are both stuck at building Fast Assembly without sufficient production to finish them quickly.
AI Manu: 10; Research 22.1; Income: 1.8; Pop 7/16; Approval:100; influence: 53
Human Manu: 227; Research 47; Income: -6.7; Pop 32.5/30; Approval:64; influence: 69
ROI analysis for the AI-save @ Turn 39.
Fast assembly: 182 Manu -> 4pop -> +4 base Raw production -> +5.5 Raw production (AI bonus etc) -> 3.37 Manu, 7.4 Research, 0.6 income
ROI: 1.85 Manu per 100 Manu
Manu Yor @ red arrow: 30 Manu -> +40% Manu -> 2.04 Manu
ROI: 6.8 Manu per 100 Manu
Rose Morrin I (*Fac in human-save)
AI Manu: 33.5; Research 18; Income: 0.9; Pop 5/8; Approval:100; influence: 46.8
Human Manu: 249; Research 114; Income: -9; Pop 17.5/15; Approval:86; influence: 45.6
ROI analysis for the AI-save @ Turn 39.
Fast assembly: 182 Manu -> 4pop -> +4 base Raw production -> +5.44 Raw production (AI bonus etc) -> 8.39 Manu, 4.48 Research, 0.23 income
ROI: 4.6 Manu / 100 Manu
Manu Yor @ Red arrow: 30 Manu -> +30% Manu -> 3.66 Manu
ROI: 12.2 Manu per 100 Manu
Proposed fix: for each colony, maintain a look-up table for each tile, where the ROI of each type of improvement is calculated. This table only needs to be updated once a building is completed or a new tech is researched. Build the improvement with the highest ROI at the tile with the highest ROI first.
P.S. it may be useful to hard code AI to research Interstellar Travel for Map size >= Medium
Update: 12/06 Links to the figures