18-01-2003 19:57									#1
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Anyone able to provide some facts/arguments on how mathematically complex civ is? From what I see, it actually seems to be more complex than games like chess, because of the way more variables in situation.

Also, the best chess computers are on same level with best chess players, and I'd expect computers to be ahead in several years. However, even the best civ AIs aren't still much of a match to the best civ players.

This actually goes after trying to tell a chess player than civ can be as mentally challenging and complex as chess is, if not more. So arguments please.

	18-01-2003 22:34									#2
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Solver

have you allowed for the fact that the besxt chess computers are optimised for the exceedingly fast computers they ruun on while an AI has to be able to work on any old crap?

	18-01-2003 22:45									#3
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I don't think anyone would code an AI good enough still for civ...

	19-01-2003 03:01									#4
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The point is you can't program rules that are really effective for a vibrant game like civ.....because it usually depends on the situation, and AI cannot adapt.

In chess computers have the upper hand over all but the best humans because computers' short term crunching of variations is unbeatable. Computers still lack long term understanding, which is why they can be beaten by good players if they force them into long term positional battles.

But it still isn't easy, because tactics usually play a role in converting any positional advantage......and the computer will usually find some ingenious tactical ways to extricate itself.

In addition you can tell a computer what openings to play, and the top programs can play all basic endgames flawlessly. This last point is a key one I think.......the deterministic nature of the game allows the machine to be fed what it might have difficulty in working out for itself.

No such thing in civ.

	19-01-2003 05:45									#5
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have to agree with spike, what makes civ so good is the human players ability to read situations and adapt to them through various playing styles, the ai , simply cannot compute this at this point.

all ais have flaws in them, even to take all the best civ players and mold it into an ai, wouldnt' work....

there are always loopholes and bugs ......

	19-01-2003 05:50									#6
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quote: Originally posted by War4ever have to agree with spike

Always said you were an insightful chap.

	19-01-2003 06:01									#7
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IIRC the chess supercomputers are a different AI then the civ AI's.
The chess AI is so good because it can check every possible permutation for the next few turns, and select the best move according to the outcomes.
The Civ AI does not compute ahead, it has to decide on the current variables on what is the best move, and then it often comes down to how well the programmers knows the game, to decide the best move. Coding a good AI for Civ isn't difficult if you take the chess approach and just try out all the possible moves....but then you'd have to find a computer fast enough to run it on .

A possible approach to create a good AI for civ, is to make it a case-based learning AI, and basically apply the best solution for each case that arises. If there isn't a solution yet for a particular case, there can be a simple fast routine to create a solution, which most likely isn't the best, but the outcome will provide data for future similar cases. This would mean though that the AI for each installation may evolve differently, and it would depend on the player actions.

	19-01-2003 06:05									#8
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yeah i agree lemmy.....i stated similar thoughts in a different thread on this

	19-01-2003 06:09									#9
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just read your post

	19-01-2003 16:41									#10
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Yeah, an AI that could count on every possible move in Civ would require some IBM supercomp to run .

	19-01-2003 16:59									#11
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It's not the combinations.......hell, millions of possibilities can be considered no problem. Rather it is the inability for the AI to understand how those possibilities interact........what in the other thread Mark_Everson calls non-linearity in the decision space.

	19-01-2003 17:04									#12
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Yeah... because there's no way a group of programmers could predict it all.

So with the current technological base a perfect AI is impossible.

	19-01-2003 21:46									#13
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Erhhmm... if you would visit DMOZ, you would know the "A mathematical analysis of Civilization II" writing by a British college maths student. Well, I have to say it's good reading and proves how Civ II uses algebra to calculate all triggers, etc.

http://www.adk24.ucam.org/civ2.html

	19-01-2003 22:09									#14
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Hey Ras, that's interesting. I did a similar analysis a long time ago to figure out what was best to build at what point of city development in civ2. Having this sort of info does indeed make writing a good AI much simpler. Essentially you do a cost-benefit analysis of each potential building or military unit, and pick the best. I don't know if Soren's approach was similar or not.

	19-01-2003 23:44									#15
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Mannon beating out god when it comes to happiness!? Yes, that's about right. Money, is the ultimate supply in civ it's sort of a mobile resource pool which can can be used any time, any place.

Although I have to say that this analysis only is valid if you start out with all the techs. Plus it doesn't factor in time and the value of sacrificing units to speed up production. Let the alone factoring the value of military units for defense and offense*.

Ultimate irony is that if you tried playing according to the true algabraic model you would quickly be toast because building settlers/caravans and cities/improvements is far more profitable than units.

*It's my belief that any prolonged war will never be profitable in Civ. The loss of units in the field and shifting production to offensive units is simply to great to be compensated by the gain in production/gold of captured cities.

	20-01-2003 01:31									#16
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Mark,

that's true, but I guess you hardly fool around with a calculator while playing Civ II. So you end up using your personal knowledge from previous experiences.

	20-01-2003 03:14									#17
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quote: *It's my belief that any prolonged war will never be profitable in Civ. The loss of units in the field and shifting production to offensive units is simply to great to be compensated by the gain in production/gold of captured cities.

Ever tried ICS? You never switch to offensive units, you just produce only offensive units (ok, some defenders, but they are just to defend the offensive units anyway).

The lack of caravans in the analysis is downright frightening. Trying to cover it, however, even with all the experience we may have about resources availability, trade formulas etc. would lead to really complex math indeed.

I want to point out that the number of variables is a real obstacle for the AI, but if they can be broken into categories, it becomes more manageable. In chess, you have one move to do, at most 16 possible pieces to look at, each with 0 or more moves. Go has even more possibilities and computer AIs utterly suck at this game.
In Civ, you have a choice for every unit, but do not have to choose which single unit to move. That makes for more computation but less intelligence. (I wish MOO3 still had IFPs so we could see if it gave more depth to the genre). You also have a choice for every city (what to build...), every other civ (diplomacy), and the combination of these factors is huge. Because every single one has big impact on the rest.

Quick formula of the number of options to be computed for a single turn for a despotic civ with one city (pop 1), one unit and knowing one other civ:
Civ: Tax/lux/science rates? (46 possibilites if I do the math right : 6/4/0, 6/3/1, etc.)
What to research? (usually around 4 choices)
City: Which tile to work? (20 possibilities + 1 for an entertainer)
What to produce? About 3 choices at the beginning of the game.
Whether or not to rushbuy (2 options: yes/no)
Unit: Which order? (8 moves + fortify or sentry or wait)
Diplomatic state: War, peace, make contact? If contact, threaten, exchange or offer tribute, and what? (at least a dozen possibilites, depending on the gold and tech of both civs)
Multiply: A conservative 46*4*21*3*2*11*12.
3 million+ possibilities.
Now in chess, you have 20 possible first moves, and a limit of about 120 possible moves in one turn (never reached, you'd have to be able to provide each piece every available move possibility - not considering pawn promotion).
Even in Go, you'd need a grid of 1700x1700 to have the same complexity for a single turn!!!!!!!!!!!!!!!!!!!!!!
The fact that some options are no-brainers in all games deosn't change the ratio much.

If you don't split that search space into bits, you have thousandfolds more possibilites than in Go, and the complexity goes increasing as the game proceeds, instead of lowering in both Go and Chess.

Now the real question is: Must one be silly to try to code an AI for such a game?

	20-01-2003 04:14									#18
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I think the hardest thing about human opponents in a game is predictability. With computers you know generally what they are going to do, but the reverse is not true

In a recent game of Civ3 against my brother, we had a our two homeland islands right next to each other. Rather than invade directly I sent a carrier fleet and invasion fleet all away around the world to attack him from the far side. I did this as it meant that he had to move the majority of his defencive units to a point furthest away from by lands making a counterattack against my homeland difficult.

An AI would not come up with such an out of the blue plan, or appreciate the consequences of such a tactic. It thus can't predict how an opponent will react. (Sure, you could programme such tactics, but there are a myriad, and the computer will never come up with new and inventive ones suited to a game and its situation)

	20-01-2003 05:52									#19
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quote: Now the real question is: Must one be silly to try to code an AI for such a game?

good point.

You have shown with simple math that calculating all possibilities in a civ game is not really computable.

I dont know how to make a good civ AI.

But I think we should keep trying. Leave the ideals of pure, perfect, unbeatable AI and simply be pragmatic. Where we cant 'make' intelligence, we can 'simulate' it
(example is AI amphibious landings which are hardcoded, but are not a part of a 'bigger picture' or a long term plan)

I strongly oppose making game less complex just for AI sake, like they did in civ3, but it is a pragmatic thing to do.

	25-01-2003 21:58									#20
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I guess "trial and error" is the way to make a good AI.

	02-02-2003 03:47									#21
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Don't you think that would take a bit long time? Not that I know anything about programming an AI, but...

	08-02-2003 08:07									#22
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A good AI is possible, but you would a computer the size of Los Angeles to use it.

	08-02-2003 08:50									#23
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quote: Originally posted by Odin A good AI is possible, but you would a computer the size of Los Angeles to use it.

hi ,



a simple updated modern PC shall do , most MAC's do excellent

have a nice day

	22-02-2005 00:47									#24
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This argument has raged on in many forms in many threads. More complexity = more expensive.

AI Complexity and sophistication is more expensive due to:

• Design Time
  
• Programming Time
  
• Playtesting time
  
• Software iterations to correct errors, flaws, bugs
  
• Higher system requirements to the end user
  
• A different type of "cost" possibily manifests itself in a steeper learning curve/micro-management requirements in the game - but not necessarily
  

	22-02-2005 01:06									#25
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Bumptastic.

	22-02-2005 01:19									#26
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I'm a good forum user. Instead of creating a new thread on a subject covered previously, I try to find where it was discussed previously.

I'll do the bump-a-rama thing.

	22-02-2005 03:00									#27
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I think a heuristic-based AI could be programmed to play the ICS well. In fact, much of its strength even for human players is that most of your options are discarded from the start as not being worth another settler, or another offensive unit.

But this does illustrate one of the challenges facing the AI programmer. The best strategies won't be known until good human players get ahold of the game and give it a more thorough playtesting than it ever could receive in production.

If the game could be shipped as a multiplayer-only game and then the AI written for it a couple years later, then we might see strong AI.

Given a good plan, computers can figure out the best way to implement that plan. Coming up with the plan is what you need a human for.

	23-02-2005 12:03									#28
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Love Chess

One of the best tbs game ever. Still Civ games takes more of my time and is a deep thinking game like chess. Have to plan and think many moves ahead or lose for lack of vison.
The AI in some Civ games can be very weak like in Call to Power2. But with modding and a new goals the AI can at times out perform human player.
Have used my chess skills to update CtP2 AI thinking. Set goals for more units to patrol its borders. Moblise forces guick to hem in human player without stripping its defense away. In chess active defense takes away offense by using a hemming in strategy. Ai's in Civ game should seek to control more open areas this way the AI stays ahead by boxing you in .

	23-02-2005 18:43									#29
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The biggest challange is to make the AI roleplay, otherwise you end up with some annoying power-gaming, super-sprawling munchkin like the Civ3 AI, and the game becomes a mundane number crunching exercise rather than an atmospheic strategy game where you lead a civilization from the dawn of time.

	23-02-2005 19:46									#30
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quote: Originally posted by shimmin But this does illustrate one of the challenges facing the AI programmer. The best strategies won't be known until good human players get ahold of the game and give it a more thorough playtesting than it ever could receive in production. If the game could be shipped as a multiplayer-only game and then the AI written for it a couple years later, then we might see strong AI. Given a good plan, computers can figure out the best way to implement that plan. Coming up with the plan is what you need a human for.

Which is why I have tempered my expectations. Since cIV is very likely to be a signficiant departure from Civ3, just like every new version of Civ has done in the past, then AI has to be retaught with the new rules, features and functions. What carries forward from previous civ versions in this regard? Anything?

I hate to be pessimistic, but Firaxis had an opportunity to fine tune the AI with all the patches, updates, mid version releases (PTW, C3C) of Civ 3, but yet the performance of the AI still had significant, unresolved problems by C3C patch 1.22. It seemed to me that the method for adapting the AI and bug patches was to fiddle with the numeric values of variables (resource scarcity) and game elements (power of FP for example).

Again, I hope I'm wrong.