[Bug-gnubg] Re: [Fwd: gnubg search function]

[Thomas Hauk]

On Thu, 27 Mar 2003, Øystein Johansen wrote:
> >2) Where does the current search function hide? I'm told gnubg just
> >performs a 1-ply full-tree search. Is this a part of eval.c? It's a huge
> >file. Can you help point me toward the function?
> 
> The search functions are all hidden in eval.c. It's implemented as a recusive 
> function. See EvaluatePositionCubeful3, EvaluatePositionCubeful4, 
> EvaluatePosition, EvaluatePositionFull and EvaluatePositionCache.

I've stared at the code for a while, but I'd like to just confirm my 
understanding:

EvaluatePosition calls EvaluatePositionCache to determine if the state has 
already been evaluated and cached in order to speed things up. If it 
hasn't, then EvaluatePositionCache calls EvaluatePositionFull. 
EvaluatePositionFull contains a recursive call to EvaluatePositionCache if 
nPlies is greater than 0; else it performs a leaf evaluation.

Am I correct to interpret a return value of 0 as "nothing went wrong" and 
any other value to mean "something went wrong"?

Does gnubg simply perform a 1-ply search out of the box?

How do EvaluatePositionCubeful3 and 4 factor into the search?

--Tom