RE: AI (was error handling)

["Stanley Sutton" <sutton at earthdecision dot com>]

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Stanley M. Sutton                sutton@earthdecision.com
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> -----Original Message-----
> From: Hans Ronne [mailto:hronne@telia.com] 
> Sent: Wednesday, January 08, 2003 10:36 AM
> To: Stanley Sutton
> Cc: xconq7@sources.redhat.com
> Subject: RE: AI (was error handling)
> 
> 
> >I haven't looked at the AI code yet, but from the discussion, perhaps
> >it's overly deterministic.  Perhaps adding some randomness 
> and feedback
> >would improve things, and make it more capable?
> >
> >For example, rather than choose one best answer, perhaps 
> having it score
> >the top 4 or 5 uses for a unit, and assigning them to those 
> plans based
> >on the weights for those uses rather than trying to pick the 
> best plan
> >always?  I know in Alpha Centauri and Civ II I sometimes use 
> offensive
> >units as explorers either because their survival chances are 
> better, or
> >because they don't have a good use other than exploring at that
> >particular time.
> 
> This is how the AI works in most cases. A unit typically has 
> a 10% chance
> of doing something unexpected. Still, I would argue that the 
> colonizer is a
> special case. Every colonizer that does not build a city is a wasted
> colonizer. There is a lot of game testing, particularly in 
> the advances
> game, to support this. The side who wins in an AI vs AI game is almost
> always the side that expands mosty quickly and builds most 
> cities early in
> the game. The determining factor is usually the terrain 
> rather than the AI
> code, which is the same for all sides, but the principle is 
> still valid.
> 

 But if you have advances that require a colonizer or engineer to build
something indirectly you seem to get into dead ends.  Maybe an
enhancement might be to have a counter, and if a unit does the reserve
action n times in a row, it forces it to do something else, or use an
alternate selection process to assign an action or plan to it?

> >Another, probably harder, change would be to add "furtur worth"
> >calculations to the process of selecting plans.  I.e.; for 
> money, if I
> >believe I can get a rate of return of 4% on an investment, then $1000
> >now is worth about the same as $1480 in 10 years.  It's been 
> quite a few
> >years since my course on "rational decision making and risk 
> management",
> >but from the discussion threads I've been reading on this 
> list, the AI
> >was designed to make the best immediate decision, rather 
> than managing
> >risk, and ignores future risk/benefit analysis entirely.
> >
> >Longer term, a GA feedback system to evaluate the unit 
> values assigned
> >by the designer would be nice, and a GP system would be even more
> >desirable.  And a lot of work.  I've been taling off and on with a
> >friend that's into AI off and on about it (He's a teacher in 
> CS over at
> >University of Houston).  I have too many current Xconq 
> projects to work
> >on to do anything serious about it right now, but maybe I 
> can work on a
> >gplayer for Xconq 8.0. :-)
> 
> That would be very nice indeed. The AI is a part of xconq 
> that can use a
> lot of improvements. The action-reaction code did make it 
> more responsive,
> but the latter is still a hack grafted on the old mplayer. I've been
> thinking about writing a new AI from scrath myself, but 
> haven't had time
> for that yet. I think the biggest problem with the mplayer is that it
> analyzes the game in a static way. The whole world is divided 
> into theaters
> or AI regions, and the mplayer then focuses on clearing one 
> theater after
> another from enemy units. What does not work well is 
> reassignment of units
> to new theaters. It will happen eventually, but only after 
> every single
> enemy unit has been cleared. So the AI fails to follow up on 
> early gains by
> sustained attacks deeper into enemy territory.
> 
> I think an AI that identifies attack vectors (main directions of enemy
> units) and throws all offensive units in that way would be a 
> much tougher
> opponent. This is how the AI in civ seems to work.
> 
> Hans
> 
> 

One thing I've noticed in several games is that the path determination
doesn't seem to work very well in a lot of cases.  I've seen hundreds of
units massed in the curve of a continent near an enemy when there is a
land path to the enemy that it never seems to find.  Do we use an A*
path algorithm for path determination?

And the other situation I've seen is where the AI has conquered the
entire world, except for a raft I had in an inland sea.  It had several
cities on the sea, but either didn't or couldn't build a sea going
attack craft to destroy the one remaining enemy unit on the board.  I
probably should have saved the game so I could run the debug and see why
it wouldn't desroy me, but I didn't think of it at the time.  I was just
seeing if the game seemed to still work after making come documentation
changes.