[Freeciv-Dev] Re: Unit-vs-stack sim (was: Cache win_chance)

[Raimar Falke <hawk@xxxxxxxxxxxxxxxxxxxxxxx>]

On Sat, Feb 23, 2002 at 06:29:10PM +0000, Gregory Berkolaiko wrote:
>  --- Raimar Falke <hawk@xxxxxxxxxxxxxxxxxxxxxxx> wrote: 
> > On Sat, Feb 23, 2002 at 04:45:46PM +0000, Gregory Berkolaiko wrote:
> > 
> > > Now let's identify the needs: precisely what information are we seeking
> > > from
> > > this potentially very complicated simulation?  How are we going to use it?
> > > [remains to be filled in]
> > 
> > I think I have described this.
> 
> Mmm, not well enough I am afraid
> 
> > > 1. Outcome of one attack is already a complicated thing: besides won/lost
> > > distribution we have a much wider distribution of the remaining health of
> > > the
> > > winner.  It is not hard to compute (it's done in win_chance) but should it
> > > be
> > > stored and used?  Or just a conditional mean(*) would do?
> > 
> > This simulation function will not anything in struct unit. It will
> > store things in the result structure (comres).
> 
> I am not sure why you say this...  Isn't it obvious?
> 
> > Yes the health loss of the units have to be considered. But I see no
> > problem in tracking them.

> On the average -- no problem.  But is average good enough for you?

It has to be since there isn't a feasible alternative.

> And you didn't take it into account in the example you considered

I described the outcome. How the caller will see it. Yes I assumed
that the caller doesn't want to know the hp loss. It has to be
exported if there are caller which want to know the hp loss.

> > > 2. Outcome of one attack will be affecting the next attack.  If it ever
> > > happens, because we have one more branch here: what if the defender
> > > decides to attack us?
> > > 3. More branching will follow: what if reinforcements arrive to the city
> > > we
> > > are sacking?
> > 
> > We don't know what happens next (neither with the next packet of the
> > enemy to the server nor in the next turn). This is a simple
> > function. There will be no intelligence in it.
> 
> but you did multiple attacks.  for most units you'd need more than one turn to
> do that.

Yes it is an extrem case. But this is necessary to show what is
intended.

> > > The present AI follows a very simple (thus unsatisfactory for some of us)
> > > mathematical principle: step-by-step maximization.  AI takes an action if
> > > on
> > > average it would be better off after this action (apart from the broken
> > > auto-attack which I will fix as soon as Raahul supplies me with the
> > > promised
> > > savegame).
> > 
> > How well does it handle unit stacks? Example: pdef1 is a good
> > defender, pdef2 is an expensive unit, pdef3 is a cheap one. All in a
> > fortress. The attacker will likely destroy pdef1, will also destory
> > pdef2 and but will be destroyed by pdef3.
> 
> What is your question here?

Will the AI correctly attack even if it knows that the attacker will
be destoryed but has killed pdef2 before?

> > > But maybe we can come up with the algorithm which would go into sufficient
> > > depth for you and be sufficiently simple for my small brain.  So let's
> > > discuss.
> > 
> > I'm now not concerned about problems of the implementation (hp and
> > veteran tracking) but about the interface. The proposed interface
> > would wrt to my current knowledge be necessary to start coding any
> > military agents. But will this interface also be good enough to be a
> > help for the server AI?
> 
> the simulation that IMO is useful to AI is:  what will happen between now and
> next turn.  The decision tree (can be much expanded).
> 
> (1)     attack
>        /      \
>     died      alive
>                 |
>               has moves?
>              /         \
>         goto end        what will we do next?
>                      /         |        |      \      
>                  run away    attack    rest    occupy city
>                     |          |        |          |
>                  goto end    goto(1)  goto end  goto end
> 
> (end) consider possible enemy reprisals until the next turn comes
> 
> The end result would be sturcture with all branches and their probs, list of
> dead units and cities and the resulting HP and status alterations.
> So very much like yours :)
> 
> But I don't think it will be very practical.

Such a tree could be constructed but this is IMHO a layer on top of
the thing I described.

> Ufff, art is so demanding...

;)

> P.S. I think I misunderstood your proposal.  I thought you want to simulate
> further than one turn.

Two or three layers on top of this one: yes.

        Raimar

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