The basics of Armies

[Theoden]

So the behaviour is actually more odd than I thought it was. I have a few theories of what could affect things:
whether the army is inside the AI's territory
whether the army is inside one of the AI city's radius
If it blocks one of their trade routes like standing on a luxury

Just some random thoughts of what factors who might be able to decide the AI's behaviour. I might also get to test some of this myself.

Let me know if you get any interesting results.

Theoden

 

[eldar]

@eldar, do you have a savegame to show that? I've heard/seen of the effect, but it's very hard to reproduce...a save would help immensely.

It was during COTM10, so I have some intermediate saves lying around, but probably none from the turn I landed my forces. I certainly wasn't expecting it! The stack was landed on the tile next to a city, and significantly overpowered the defences in that city, if that makes any difference.

 

[Arathorn]

Were you defending a city? They'll attack cities like nobody's business. It's just armies "in the field" that are safe. Cities are essentially always targets. If you have the only "enemy" city on the continent, they'll suicide every single offensive troop against it, regardless of the defenses. An army is safe from attack OUTSIDE a city, even if there are no other targets. Does that explain it?

Arathorn

 

[eldar]

Nope, my stack was attacked on the inter-turn after I first landed my troops. They weren't in a city, they were in the open, next door to a city.

 

[Arathorn]

I would like to see that save, if you have it. And we should maybe take this discussion elsewhere....

Arathorn

 

[Offa]

Eldar, the same thing just happened to me. I landed a 2 muskets army (in a caravel) on the babylonian continent in my current game, intent on doing a bit of pillaging only to get mercilessly attacked and killed on the ibt. A complete waste of an army.

The babs did have a lot of units to spare, as this is an AWS variant played as the Byzantines (thanks to Handy for the idea). I guess having a partially loaded army didn't help.

I have a save from 2 turns before the army landed but not of the event itself.

I am still considering landing an army on the Egyptian continent (if I can find a free tile) so may have another example soon. Then again, I might not waste the army as it is beginning to look like poor play.

 

[MeteorPunch]

I've heard this before. If the army is the only target they will attack.

 

[Arathorn]

@Offa, were both muskets vets? That is, did the army have at least 8 hps? If so, I definitely want to see it.

@MeteorPunch -- too many counterexamples where the army IS the only thing on the continent and is not attacked. That's simply not true. I've had armies as the only unit not of the AI's, while at war with that AI, for 100s of turns and not been attacked.

Arathorn

 

[AlanH]

Eldar, the same thing just happened to me. I landed a 2 muskets army (in a caravel) on the babylonian continent in my current game, intent on doing a bit of pillaging only to get mercilessly attacked and killed on the ibt. A complete waste of an army.

What were Babs attacking with?

 

[eldar]

I would like to see that save, if you have it. And we should maybe take this discussion elsewhere....

Typically, I have the save from the turn after, but it's a little too late by then as I'd captured 2 cities. The first save before that is some 16 turns before, with my Army at one end of my continent and nowhere near the as-yet non-existent boats required to transport them.

 

[Offa]

I have gone back to my old save and replyed a couple of turns to recreate the army landing. In the save I enclose there is a 2 vet musket army in a caravel just to the south of the eastern tip of the babylonian continent. You just need to land the army onto the bab continent and press spacebar. I have tried a few times now, and if the army lands on the flat it gets killed at once, and if it lands on the available hill it will survive one turn, but still gets attacked straight away (implying it could have been filled up in the meantime to be a 3 musket army). The babs have cavalry, lots of cavalry.

land the army and wait

 

[AlanH]

The babs have cavalry, lots of cavalry.

Vet cavalry vs 8 point Musket unfortified (just landed) on flat terrain is 25% success rate. That looks like the kind of odds the AI would be prepared to accept. The hill situation is a little less likely to be attractive to them, at 15% success rate. But factoring in the retreat factor they may still be prepared to give it a shot.

Point is I don't think an army per se puts off AI attackers. They just decide on the basis of probability of a kill. They stupidly only look at the success probability for an individual attack, which is why the same army at 12/12 on the flat would be seen as unassailable, with a probability of success for a vet cavalry of only about 6%. Maybe the decision threshold is something like 10%?