[BTS] Suicidal AI?

[Fish Man]

I finished a deity domination fractal game today but saw some very strange things.

The first was when I attack Shaka. I nuked his capital, leaving behind about a dozen wounded infantry, and then moved in about 30 tanks. The next turn he...slammed about half those infantry into my tanks and did pretty much no damage. I...didn't expect him to be this stupid, even being Shaka and all, but oh well.

The next instance was when I was fighting Willem. I basically moved in 50 modern armor next to his city. The next turn he nuked my modern armor, hitting not only my stack but irradiating his land and also decimating his own city...both of us were wiped.

Has anyone seen this behavior from AIs before? I'd expect this level of batshit crazy from Shaka maybe but definitely not Willem. Does anyone know what causes this to occur or not to occur?

 

[AcaMetis]

What did Willem's city have to defend itself against your Modern Armor doomstack? Not that I expect the AI to be clever enough for it, but if Willem was going to lose the city anyway than he might as well nuke it himself and take out your army in the process.

 

[Fish Man]

What did Willem's city have to defend itself against your Modern Armor doomstack? Not that I expect the AI to be clever enough for it, but if Willem was going to lose the city anyway than he might as well nuke it himself and take out your army in the process.

That's what surprised me. I never in a million years expected the AI to be this clever, because this was what I would've absolutely done as a human player. It seemed like I gambled on the AI caring for its citizens and found out that they cared just as little as the human player normally does.

On an unrelated note: I'm also pretty sure the AI cheats in specific areas. Namely, detecting naval units. They know where your all your ships are, all the time. Period. Your transports are never safe...

 

[Lennier]

It's not quite that they know where all your ships are. The AI has a visibility of 2x movement range. On land, that extra visibility over humans isn't very obvious. However, naval units, especially late in the game, have large movement ranges and so when you run out of your visibility range of the AI, they can still see you.

 

[rah]

because this was what I would've absolutely done as a human player.

Wouldn't you have nuked the square on the other side of their stack to avoid hitting your own city. And used 2

 

[Fish Man]

Wouldn't you have nuked the square on the other side of their stack to avoid hitting your own city. And used 2

They did use 2. Also tactical nukes have a limited range so I assume that's why.

Doesn't matter. I came back 10 turns later with another 50 modern armors and this time wisely let my vassals take the hit. Then out of spite for daring to think he had a chance against me I wiped out every single city of his and refused his pleas for capitulation. Took a good 2 hours to get to the islands, especially with All-Seeing Omniscient Destroyers (tm) but was well worth it.

 

[Fish Man]

It's not quite that they know where all your ships are. The AI has a visibility of 2x movement range. On land, that extra visibility over humans isn't very obvious. However, naval units, especially late in the game, have large movement ranges and so when you run out of your visibility range of the AI, they can still see you.

Ah, that must be it.

Well, functionally omniscient then. 20 tiles (for 10?-move destroyers) is more than the width of many continents on fractal/continent maps.

 

[6K Man]

I think in a lot of cases, it’s just dumb, not suicidal.

Example from this week: I’ve captured an AI city in the early industrial era. The AI is preparing a counterattack, with a stack full of siege weapons. The city I’m in is deep in AI culture, with roads everywhere. A smart AI would keep its stack away from the city full of my units until it was ready to attack. Instead it moved the stack up next to the city (using up all its movement points). The city is filled with Cuirassiers and Cavalry, with a handful of other units for defense.

If the AI kept the stack 2 tiles away, I wouldn’t be able to pre-emptively attack it at all.
If the AI kept the stack 1 tile away, I could attack with my mounted units but they’d all be exposed outside the city after attacking.

Instead, I was able to attack the AI stack, flank all the siege to death, maintain my relatively safe position inside the city, and basically wipe out 1/3 of Boudica’s forces. It’s an elementary mistake that a human would never make (or would reload, if done accidentally), but the AI does this stuff all the time.


And yet… I’ve been in games when the AI had a strong stack, attacked my slightly-weaker stack with 3 of its units, lost each time, and broke off combat. Makes me wonder whether if it is programmed to break off attacks if it is unlucky (or can’t damage your top defender), or if it would keep attacking for only so long as it had better-than-average odds to wipe me out? I'm not sure whether AI personality has anything to do with it, either...



Re: nukes – I thought you couldn’t nuke your own territory? Or perhaps it’s just that you can’t nuke any territory with an AI unit you’re not at war with.


@ Lennier – I thought AI visibility range was movement rate +2 for ships. 2x movement range is just unfair.

 

[Fish Man]

I think in a lot of cases, it’s just dumb, not suicidal.

Example from this week: I’ve captured an AI city in the early industrial era. The AI is preparing a counterattack, with a stack full of siege weapons. The city I’m in is deep in AI culture, with roads everywhere. A smart AI would keep its stack away from the city full of my units until it was ready to attack. Instead it moved the stack up next to the city (using up all its movement points). The city is filled with Cuirassiers and Cavalry, with a handful of other units for defense.

If the AI kept the stack 2 tiles away, I wouldn’t be able to pre-emptively attack it at all.
If the AI kept the stack 1 tile away, I could attack with my mounted units but they’d all be exposed outside the city after attacking.

Instead, I was able to attack the AI stack, flank all the siege to death, maintain my relatively safe position inside the city, and basically wipe out 1/3 of Boudica’s forces. It’s an elementary mistake that a human would never make (or would reload, if done accidentally), but the AI does this stuff all the time.


And yet… I’ve been in games when the AI had a strong stack, attacked my slightly-weaker stack with 3 of its units, lost each time, and broke off combat. Makes me wonder whether if it is programmed to break off attacks if it is unlucky (or can’t damage your top defender), or if it would keep attacking for only so long as it had better-than-average odds to wipe me out? I'm not sure whether AI personality has anything to do with it, either...



Re: nukes – I thought you couldn’t nuke your own territory? Or perhaps it’s just that you can’t nuke any territory with an AI unit you’re not at war with.


@ Lennier – I thought AI visibility range was movement rate +2 for ships. 2x movement range is just unfair.

That's basically one of the meta strats for deity cuir/cav wars. Declare on enemy, wait for them to move their medieval crap to open ground, and crush 50 units at once with flank attack/easy 1v1s outside city walls. After that they have basically only token forces hiding inside city walls and you can steamroll them at your leisure.

With the industrial/modern deity wars though it's much harder. Once they have railroad, artillery, and infantry, don't even think of invading with less than 50 units yourself. They will have built an absurd stack at this point, especially the infamous unitspammers (looking at you Giggles...), and can reach you anywhere with railroad. And if you think two dozen tanks is enough, well it's not to take on every single artillery and infantry the opposing enemy army has. On the first turn, even if you have a hundred modern armor, they will throw everything they have at you - dozens of artillery, infantry, cavalry, tanks, marines, totaling up to absurd amounts. I've once seen an AI sack 200 units at me in a single counterattack (ofc that did nothing, I had modern armor, but if I had anything less I would've been wiped) at a single turn. Then again, I had nukes at that time, so I guess the opposing army decided they'd rather die with honor than die being obliterated hiding behind city walls like cowards.

 

[AcaMetis]

Re: nukes – I thought you couldn’t nuke your own territory? Or perhaps it’s just that you can’t nuke any territory with an AI unit you’re not at war with.

The latter, for reference. I'm not sure if the game will allow you to nuke your own territory if there isn't an enemy unit within range, though.

 

[Bibor]

Yes, this is quite normal behavior for some AIs. The modifier is called “Base attack odds change” in the leaderhead xml. The higher the number, the higher the suicide rate. You can use this to your advantage and lure aggressive AIs into suiciding their stacks

Quote from wiki:

iBaseAttackOddsChange Modifies the Attack odd chance, to make an AI think that a battle is more likely to be won, thus having him more likely to attack (without any real effect on the battle). The total modifier is: iBaseAttackOddsChange + rand(0, iAttackOddsChangeRand) + rand(0, iAttackOddsChangeRand)
(0 (most leaders); 6 (Ragnar, Napoleon))