[1.3.0][5256] Bugs in the AI division template builder

[tom_jones]

Don't know which of the issues reported for earlier build are considered fixed, so taking note of what seems to persist.

#1 appears to fail at fitness calculation

a new game started in 1.3, the AI evaluates starting ITA template as follows:



The first upgrade the AI attempts is to add artillery support. In theory, this would be considered a decent move. Unfortunately, the upgrade is then considered by the AI as quite an opposite:



You're seeing it right, the overall fitness score drops, even though target match score increases and the added battalion supplies more stat-wise than it takes:



end effect, the AI never switches its divisions to the newly produced template, and happily cranks out the old ones.

This behaviour raises two questions:

1) fairly obvious, how does the AI manage to arrive to such counter-intuitive fitness score?
2) why does the AI spend points on change to template, if the result is --by the same AI-- considered worth less than what it already has available? This is especially puzzling given the next issue:

 

[Omghax]

Thank you for your report. This issue exists in our internal database and should hopefully be adressed in the near future.

 

[tom_jones]

#2 the AI makes... questionable... upgrade choices.

you may think it's weird the AI gets lower score for including artillery support. But it's actually also weird that it includes one in the first place.

Why? Because it does so even though it's explicitly told not to.

templates_ITA.txt

infantry_default_ITA = {
(..)
 target_template = {
  weight = 0.9
  match_value = 300.0
 
  support = {
   engineer = 1
   recon = 1
   field_hospital = 1
   anti_tank = 1
  }
 
  regiments = {
   infantry = 9
   artillery_brigade = 3
  }

as you can see, the AI is asked to aim for a template that doesn't have artillery support included. It has other, different things it could pick to place in the infantry division instead, like artillery_brigade, or another infantry battalion, and yet it picks something it's not asked to, even though it then doesn't consider it an upgrade itself.

(incidentally, that naming scheme might be wrong, in the previous build I had to name specialized templates as type_TAG without the 'default', for the game to actually notice them. just in case it is, I've removed the artillery support also from the generic template. The AI still included one as its first choice. Then I set the weight of target template to 1.0, to --in theory-- eliminate the chance of the AI choosing not to follow the target down to the t. Both for the ITA variant, and the generic one, just to be on the safe side. Didnt' do a damn thing, the AI still chooses to put the artillery battalion as the first upgrade, then evaluates it has worse fitness than what it started with, and doesn't use it.

 

[tom_jones]

#3 replaces entire column with different unit type instead of adding a new column, when asked to include single unit of given type in the template

example: JAP starts with 12 infantry battalions in its infantry template. If the target_template includes a single unit of different type, like armoured or mobile battalion, a logical approach would be to either add this single unit in a newly created column, or if the AI has to switch existing column to different type (which will convert 3 infantry battalions to e.g. 3 tanks) at the very least the AI should remove superfluous units, as it will cost it no xp points to do so, and the result will match far better the actual target_template.

(for the record, the AI has more than enough xp points to spare to add a new column, it wasn't being held back by that)

Instead, the AI just swaps the entire column and calls it a day. The patch notes mentioned it should be now able to remove battalions from the template, but it doesn't appear like it wants to actually do it :/

 

[tom_jones]

#4 AI still replaces support battalions rather than add them

possibly related to

- Removed block from AI preventing it from adding more support than columns of regiments.

If that's the case, the bug still seems to be well and kicking:





(yes, the target template asks for both the recon and anti-tank supports)

edit: 2-column templates replace their supports instead of adding 3rd, and single column templates replace their single support so yeah, definitely seems related to that supposedly fixed block.