Complete.Org: Mailing Lists: Archives: freeciv-ai: April 2002: [freeciv-ai] Re: Approximate win_chance

# [freeciv-ai] Re: Approximate win_chance

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 To: Gregory Berkolaiko Cc: freeciv-ai@xxxxxxxxxxx Subject: [freeciv-ai] Re: Approximate win_chance From: Raahul Kumar Date: Thu, 18 Apr 2002 18:54:56 -0700 (PDT)

--- Gregory Berkolaiko <Gregory.Berkolaiko@xxxxxxxxxxxx> wrote:
<snip>

I like your approximation better than the current system. You have me convinced

> Current system:
>
> A_rating = A_strength * A_HP * A_FP;
> D_rating = D_strength * D_HP * D_FP;
>
> chance = A_rating^2 / ( A_rating^2 + D_rating^2 )
>
> My formula:
>
> chance = A_rating^5 / ( A_rating^5 + D_rating^5 )
>
> I believe diminishing returns kick in sharply. Would using the formula
>
> chance = A_rating^6 / ( A_rating^6 + D_rating^6 )
>
> fix the problem of absolute error sometimes being 15%. You should have
> mentioned how often those values crop up.
>
> Power 5 works best (better than 4 or 6).  Not very often.  You can
> experiment with the code I attached.

That's what I don't understand. I assume higher powers should always work
better. More precision, less errors. Yet your results show differently. I am
suspicious. I demand an explanation.

> This performs way better but for some weird cases it still gives an
> absolute error of about 15%.
>
> Is there any way we can avoid calling approx win_chance when that happens?
>
> The problem is that I don't know beforehand when such thing would happen.
> But I am still thinking about it...

There must be a range of some weird values.

Aloha,
RK.

It is not the mountain we conquer but ourselves. -Sir Edmund Hillary

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