Combat AI bug in 1.21

[Pyrkaige]

It appears some of the changes in the recent patches may have unintentionally lessened the ability of the AI to wage war in a coherent fashion. Here's something I ran into recently in a Monarch game, playing as the Egyptians going up against the Greeks. They have:

150 Rifleman
10 Longbowman

I have:

60 Tank
50 Infantry
25 Cavalry

The game is at the end of the Middle Ages, and the Greeks are in a 12 city block next to me, with the same techs as I and a decent amount of cash. They have the Art of War and all their cities are linked via railroad, so there's definitely the possibility of them making an incursion difficult. I spy them out and see that they have resources to build better units at any time, and decide to take them before they do so. I capture Corinth and clean out a number of riflemen sitting outside the city, taking them down to around 130 of that unit. I also move 10 tanks towards the next city, Byzantium, in preparations to take it the next turn. I move a decent amount of tanks and cavalry into Corinth at the end of the turn and hold my breath, waiting to see how it responds.

First, the AI uses about half a dozen riflemen & longbowmen to try to take down some of my lone tanks, and does actually get one. Then, amazingly, it moves over 70 riflemen next to Corinth, which I just took from it. To do this, it has to go by my tanks, so about 1/3 of its units are damaged once they get next to the city. Since these units all have one movement point, they can't actually hit me that turn, of course. It also dumps a few riflemen into the threatened Byzantium, but certainly not many given that it's the only city I can take on the next turn.

So, I naturally pull all the tanks I can muster into Corinth and (using their 2 attacks each) manage to damage or kill all 70 of the units it conveniently placed next to the city. I also take Byzantium, which wasn't adequetely protected even though the AI still had over 50 other units it could have put into the city. The next turn it tries the very same thing; moving about 35 units next to Corinth, and I make short work of those, too. At this point, the Greek's once large force has suicided down to almost nothing, and I can walk through and clean up the rest of the cities.

Has this been a common way that the AI is working in combat? I didn't remember seeing this when the game was first released, and it seems like it might have to do with the fact that traditionally defensive units will now act offensively if there aren't any other options around. It seems the AI would work better if it did a few other checks regarding war, including:

1) If money is available, upgrade at least a certain percentage of the units to the highest defensive unit available, especially during war when going up against an opponent with a much higher attack ability (tank vs. rifleman is a joke, even when the rifleman is defending 25+ population cities).

2) Don't attack with single-move "defensive" units in a scenario where you could lose more cities by doing so. It seems that keeping the cities you have should always be a higher priority than attempting to take back one, unless a Civ is so weak it's just doing an annoyance suicide attack. If the AI had moved 20 of its riflemen into the few cities near my border and upgraded 5 in each city to Infantry, it would have been much harder to take it. Instead, it wasted them by trying to overwhelm in numbers, when the units involved didn't have enough moves to even do an attack on that turn.

3) Produce offensive units, instead of more of the same defensive one. I've seen this in a lot of games recently, where the AI for many civs just keeps cranking out defense (even in peace) instead of making enough offense to be a serious counter-threat to an attack. Again, this seems to be tied to the fact that it views all units as potentially offensive, but of course some units are much more offensive than others. In this particular scenario, the Greeks never upgraded their units until they got "Computers" just before I finished them off, and cranked out a few Mech Infantry. By that point it was far too late to do them any good, of course.

Is there any way to fiddle with the editor and raise the likelyhood of the AI doing any of this? I haven't played with that much, since I normally just stick with the default game rules and try playing at a higher level to help balance it out. Anything beyond Monarch just seems to move into the AI cranking out more of everything, though, not doing it more intelligently. Unfortunately, I don't have a saved game from this, as it was a week back; but I thought I'd toss this out to see if the community has been seeing the same in these last few patches.

[dexters]

Refresh my memory, aside from Tanks, which units have ranged attacks that allows it to fire at incoming units within a certain tile away from it?

[Sean]

Refresh my memory, aside from Tanks, which units have ranged attacks that allows it to fire at incoming units within a certain tile away from it?


Any fire-arm unit with a movement of two or better. Cavalry and tanks.

[Timeline]

and Mech Infantry

[notyoueither]

Seems as if some of Soren's adjustments are having unfortunate consequences. Are other people noticing the AI attacking in gangs more? Very good development, until it's gangs of foot to the slaughter.

Did the Greeks lack the resources for better attackers? I've seen the Longbow regression from civs that lack horses and/or rubber, oil, etc.

To answer your question, yes in the editor each unit has flags for AI use. If you check, you'll see that MechInf, Infantry, and Rifles are now viewed to be offensive for the AI. Experiment with switching this off for Infantry and Rifles. That might have resulted in your Greek opponent having more Tanks and/or Cavalry.

[Pyrkaige]

Did the Greeks lack the resources for better attackers? I've seen the Longbow regression from civs that lack horses and/or rubber, oil, etc.

The Greeks had at least one of every resource, when I spied on their cities; they did end up making a handful of Mech Infantry (and I think a few tanks) by the end of the war, but by then it was far too late. At the very least, they could/should have upgraded some of their riflemen to Infantry, since they had both cash and the Art of War.

After thinking about this more, it would seem the most glaring problem (apart from sending out waves of single-move units to attack a Civ with plenty of tanks) is the AI's lack of appropriate defense when attacked. If the Greeks had sent 10-15 riflemen to Byzantium when I had 10 tanks sitting outside of it, and upgraded them all to Infantry, it would have been much harder for the tanks to take them out. Instead, it sent a token 5-6 riflemen there, which were easy to run over. This seems to happen a lot; a Civ will have plenty of defensive units overall, but dole them out sparingly to the citites that are actually going to be attacked next. There should be a better "threat assessment" during war with an appropriate response each turn, so that each civ best protects the cities (and to a lesser degree, units) that are most likely to be attacked.

To answer your question, yes in the editor each unit has flags for AI use. If you check, you'll see that MechInf, Infantry, and Rifles are now viewed to be offensive for the AI. Experiment with switching this off for Infantry and Rifles. That might have resulted in your Greek opponent having more Tanks and/or Cavalry.

I'll have to play around with those flags and see if that makes a difference. As a rule I like to play with the "real rules", so I rarely mess with anything in the editor when playing. Overall, those defensive units should act offensively, when warrented. The AI should be smart enough to know not to run single-move units against a Civ with tanks, however, and it should build more offensive units when given the chance. Civs should try to maintain at least 20-35% true offensive units, when deciding what to build during peace. Some of them do, but many now seem to just keep cranking out more defensive units that don't deter threats.

[notyoueither]

The problem arrises when the AI *thinks* that Rifles or Infantry are offensive. Thus, it is building plenty of offensive units, which unfortunately lack the attributes to go toe to toe with Tanks, one on one in the open field.

Ironically, Soren introduced this in a patch after many observed that the AI would role over and play dead once you defeated their offensive units.

Hopefully, he will be able to add just a tad more refinement, however I'm not sure how. Perhaps it would not be too difficult for him to add an AI use flag, Fast Offensive which would receive the preference in the build decisions. That way, the AI would still use Infantry if that's all they had left, but would build more and better attackers when at peace.

[Colonel Rhombus]

Dunno how much of an AI bug this is. Such tactics were tried extensively and for years by human generals in WW1.

I've just started my first serious game of v1.21f and I can't wait to play the meat-grinder scenario with my (and the AI's) hapless footsoldiers.

[Gramphos]

Do you have a save?

I want to chavk if it might have something to do with multiple strategies.

[Pyrkaige]

Originally posted by Gramphos
Do you have a save?

I want to chavk if it might have something to do with multiple strategies.

Unfortunately, I don't have a save from it, although I've also seen this to lesser degrees in other games recently. It may be related to that issue, although I don't know if there's a specific number of any particular unit that is flagged as "offensive" and "defensive" within the game; it seems that units with a particular flag are just all judged equally, even when they obviously aren't equal. (Which is why the AI will make 150 riflemen but no cavalry, even when it has the necessary resources.)

Originally posted by Colonel Rhombus
Dunno how much of an AI bug this is. Such tactics were tried extensively and for years by human generals in WW1.

I've just started my first serious game of v1.21f and I can't wait to play the meat-grinder scenario with my (and the AI's) hapless footsoldiers.

Well, if all the AI can produce is riflemen, that would be one thing; it would still be a stupid strategy to take them up against tanks, however, especially when the borders in Civ prevent a one-movement unit from ever attacking offensively in a single turn. The combination of building too many non-offensive units and trying to run them against units much larger makes for very boring fights, if useful for turning out GL for the opponent.

The combination of the three AI missteps listed above make for a rather poor attack method. This seems to be true all the way to Deity level, although of course having a huge building bonus helps the AI just because it has more chances to build units, which creates a better possibility of building something useful. Given that the Civ line of games (thankfully) aren't pure war games, I wouldn't expect too much effort to be spent on war calculations. Fixing the issues listed here hopefully wouldn't take too much tweaking to the AI setup, and would create a more robust opponent.

[Galerion]

I've noticed one interesting thing about how the AI handles it's HUGE stacks of defenders mentioned above. The AI (in my games) only seems to be able to control one of this kind of stacks. The stack seems to be sent to the area that was reacently attacked by my forces. Beacuse of this I always attack at two points. My main attack force goes for the primary target, and when I see the AI respond to this attack with a huge stack, I launch my second attack. The second attack is made on a target which should be located a few cities away from the first. I have noticed that the AI VERY OFTEN goes after these new attackers. Pre-railroads this will cause the AI to spend several moves on moving his stack, without being able to attack. At this point my primary target is down, and with the remains of the primatry attackforce I go for the next city. This causes the AI to move his stack again towards the new threat. I've often been able to manipulate the AI in this way. Making myself immune to powerful counter attacks.

[Panag]

Originally posted by notyoueither
Seems as if some of Soren's adjustments are having unfortunate consequences. Are other people noticing the AI attacking in gangs more? Very good development, until it's gangs of foot to the slaughter.

Did the Greeks lack the resources for better attackers? I've seen the Longbow regression from civs that lack horses and/or rubber, oil, etc.

To answer your question, yes in the editor each unit has flags for AI use. If you check, you'll see that MechInf, Infantry, and Rifles are now viewed to be offensive for the AI. Experiment with switching this off for Infantry and Rifles. That might have resulted in your Greek opponent having more Tanks and/or Cavalry.

hi ,

they attack in gangs , but they where better of if they would attack in pockets , small groups of several units .
also ; the AI never uses a tactics , example , to surround a city , put a unit on every single tile and wait until the city is down a bit , okay , most people shall not like that , and that is good , but the AI should at least stand on two-three even four squares .

have a nice day