[Freeciv-Dev] Re: [RFC] Caching AI values

[Raimar Falke <hawk@xxxxxxxxxxxxxxxxxxxxxxx>]

On Tue, Mar 19, 2002 at 01:39:34PM +0000, Gregory Berkolaiko wrote:
> While doing flying stuff, AI computes a few values which should be cached 
> (like the number of air targets around a city).  I can see 2 approaches to 
> such caching:
> 
> 1. Compute these values at the start of the AI player's turn.
> 
> 2. Compute these values as needed and then record them into a struct 
> together with the time they were computed.
> 
> I favour the second approach greatly.  First, you don't have to trace the
> spagetti AI calls to see to it that the values are initialized before
> being accessed.  Second, you don't have to decide beforehand if you should
> waste CPU initializing them at all or it's too earely in the game to do
> that (doesn't make much sense to count the number of air targets before
> you discover Flight): in approach 2 they would be initialized as needed.
> 
> But to execute 2nd approach efficiently, one has to have the "time"  
> concept.  I remember Raimar and Co talking about game.turn variable or
> somethign like this.  My time has to be a bit more precise, I think: there
> are two AI movement phases per turn and "time" should distinguish
> between "turn 10 start-turn" and "turn 10 end-turn".
> 
> Please provide me with insightful remarks and great suggestion on these 
> matters.

IMHO the second approach favors the spagetti AI. I can image a
description like "if foo is called from bar with option X than the
value is updated else the value is set by foobar".

IMHO the granularity of pre-turn, post-turn is too coarse. But this
depends on exactly what you try to measure.

There is another solution possible:
 3. Update the value whenever this is necessary

        Raimar

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