The AI and nukes

[Michael Daumen]

Has anyone ever seen an AI-controlled civ have nukes and not use them? I have a scenario with missiles aplenty but the computer won't attack, even with only one possible city to target!

[techumseh]

Yes. For some reason the AI is not always prepared to use nukes first, or at least right away. I don't know the factors, but it may have something to do with a) relative strength of the AI civ and your own, b) whether or not you also have nukes and, c) the type of government of the AI civ, ie: fundamentalist more likely, democracy less. All of this flys out the window if you use nukes first. I've never researched any of this, it's just based on casual observation.

One thing I do know is that any city with 3 or more units in it, or next to it is a target, regardless of the range to an actual AI nuke. 2 or less and the AI will NOT nuke the city.

[ravagon]

Originally posted by techumseh

One thing I do know is that any city with 3 or more units in it, or next to it is a target, regardless of the range to an actual AI nuke. 2 or less and the AI will NOT nuke the city.

I think there may be a unit cost involved too though. If the AI is expending 160 (?) shields worth of nuke it wants to get a bang for its buck so to speak.
I'd think a city with a battleship and a carrier would warrant nuking ... ?
Can't remember offhand as its been a while but I'm sure I had something like that happen to me in one of my first ToT games.

Not that this seems to have any consequences for unit stacks outside of cities mind you.

[techumseh]

Originally posted by ravagon


I think there may be a unit cost involved too though. If the AI is expending 160 (?) shields worth of nuke it wants to get a bang for its buck so to speak.
I'd think a city with a battleship and a carrier would warrant nuking ... ?

Not unless the programmer decided they were. (S)he made the decision, not you or I. I've tested this. Two units, safe. Three units, gone.

[Michael Daumen]

Interesting . . . .
Thanks guys!

[Michael Daumen]

Grrr, the results are very inconsistent. I playtested by nuking some AI cities and was retaliated upon about half the time. My city had three units in it at all times.

[ravagon]

Bah humbug.
Well, I tried again last night - loaded up a save game from MP's jihad scenario (Playing as the Byzantines).
Now I know this isn't exactly the best sort of testing but I wanted to really stack the odds a bit.
Had about 20-odd cities, some captured, and was at peace with everybody when I cheated in a dozen odd nukes and sneak attacked everybody (Put rep. to despicable).
Then I cheated in a few nukes for each of the others and sat back to watch the fur fly. (Note that nobody had Rocketry/Manhattan - just the weapons I cheated in).

I had previously set Alexandria up with a BB and CV but nothing else and had boosted the pop to 20 to leave it in perpetual disorder to ensure no more units were built.
Most of my other cities had 6-10 or so units of various sorts and while Alexndria wasn't hit first it they did get around to it eventually, still leaving several other cities (with half a dozen or so units apiece) alone.

It didn't really bear out my suggestion that unit cost was a factor but the city in question did only have 2 units.
Maybe it includes the total cost of all units to determine preferential targetting - and maybe location (or improvements?) as well?

More now than I was before ...

[DarthVeda]

I always thought the AI targetted the city with the biggest cluster of units?

[techumseh]

Originally posted by DarthVeda
I always thought the AI targetted the city with the biggest cluster of units?

I think you're right, though for reasons not yet understood, it doesn't always launch nukes when it has them. Ravagon, your results are a surprise for me. I've always been able to avoid a nuke attack through dispersal, ie. 2 or less units in or adjacent to the city. Has anyone else had a similar result?

[ravagon]

It occured to me that testing AI's use of nukes in a dark ages scenario might not have been the most sensible (well, duh ) thing to do so I might have another go with the WW79 scenario tonight if I get the chance.
Some of my cities were outside the range of the weapons starting point (although I have some memory of this not being relevant for the AI. ie: It paradrops them from anywhere on the map regardless of range to target? ) and with most units having shield costs of 20-30 or so it may have skewed a few results.
This is mainly assuming some sort of system as that Xin suggested in his Second Front strategy thread (In the AOW forum IIRC so it may be lost now) whereby light transports carrying a couple of infantry would never invite a shell (missile) attack whereas heavy transports carrying anything, or light transports with an armoured unit (I've forgotten their individual costs) would.
It is obviously different in some way of course, hence AI's never using nukes on unit stacks outside of cities.
As a starting point (and assuming the AI doesn't place higher targetting value on modern units with higher HP/FP, movement, or different domains or somesuch ) there probably shouldn't ever be an attack on a city with, say 3 infantry (total cost of 150) by a nuke (cost 160?).
Might play around a bit to try and find some sort of cutoff point ...
This is also assuming no contribution from city pop, improvements, capitol etc, which is by no means necessarily valid.
Any input/suggestions welcome

techumseh: Any idea (roughly speaking of course) about the specs of the units in those cities of yours that were/weren't nuked?
I'd be willing to bet that at least a few of them were defensive units, mech/rifle, etc (ie: generally seem to have a lower shield cost)... ?

[techumseh]

Not really. I've been using it as a strategy for dealing with nuclear armed adversaries when I haven't yet built a complete SDI system (which is almost always) for so long, that I just take it for granted. Whenever I get nuked, it's inevitabaly because of an error on my part.

This isn't to say that just because there are 3 or more units in or adjacent to a city, it necessarily will get nuked. Only that, in my experience, a city with 2 or less will NOT get nuked.

[ravagon]

What a nitwit! Ran through it and then left my notes on my desk ...

Oh well, to summarise the main points from memory

(1) Unit quantity is not the only contributing factor as to which cities get hit.

(2) Unit quality is definitely a factor (I think the only attribute seems to be the shield cost but I'm still not entirely sure).

(3) City size (or possibly some other city attribute that I couldn't quite pin down - I'm fairly positive it was the size though as most of the cities seemed to have similar improvements) is also a pretty major factor.

(4) I'm starting to have serious doubts about whether AI range is in fact infinite. It certainly didn't seem to be.



Ran through the ww79 scen (modified) 1st turn 3 times - (as a bit of a test to see whether or not there was any random factor in the targetting - identical results every time) - from a save just after I'd thrown a few nukes at every civ on the planet, in a series of "sneak" attacks, then having given each Civ a half-dozen nukes or so.
Playing as the Sovs - simply to give everybody a shot at me - or so I thought.

First up - the Neutrals
- first target - Vladivostock - Garrison - 1 armour, 1 aegis cruiser
- second target - Stalingrad - Garrison - 1 mech, 1 rifle
- third target - Kharkov - Garrison - 1 armour, 1 rifle + 1 adjacent engineer. also

Second up - Western Euros
- hit 8 cities altogether - Berlin, Omsk, Moscow, Riga, Leningrad, Novosibursk + 2 others - most of which had 3+ units - except Moscow which had a nuke and an armour, and Berlin which had only a mech garrison but a half-dozen others adjacent in the blast radius - including one of their own partisans.
Nothing terribly surprising, but then, absolutely no nukes from anybody else for that first round.
Not only that but my BB/CV city (Murmansk) wasn't touched either...

It wasn't until I went back and checked the Initial city sizes (unchanged from the scenario) that I made the correlation - Moscow, Stalingrad, Kharkov etc were all pretty large (size 16+ IIRC), hence could have been targetted on that basis. Vladivostok was size 14 and had a couple of "good" units and the rest could have been hit for a combination of being >12 and several (a mixture) of units.
This seemed to be borne out by playing on for a couple of dozen turns and rebuilding somewhat - I got hit again by about a single nuke apiece each turn courtesy of the ME and the Western Euros - but I think they were only those cities that hadn't already been hit and which had about 4 or more mech/Infantry as garrisons (I think my cities all had populations of 12 or less by this stage).
Iin most cases I could put 4 new units (mainly mech again) in a city that had already been hit (and had a pop of about 7-9 IIRC) before adding a fifth resulted in a restrike.
Murmansk had the BB/CV throughout the whole thing, and added a missile unit and a mech unit and was still never hit. City size stayed at 6 the whole time IIRC.

There didn't seem to be any nuclear response at all from the US or Indians (ever!) and only one or two total thereafter from each of the Neutrals and Chinese ... Reasons unknown ... Weapons not having infinite range might rule out the US but this wouldn't really explain why the Chinese did so little?


Phew!

[Henrik]

They dont have infinite range, but any nuke can be launched as if it was in any city or sub.

Ie, any city within nuke range of you can launch nukes at you even if there is no nukes in it (there has to be a nuke in some other AI city though).