Author: Christophe Theron
Date: 08:55:15 10/07/99
Go up one level in this thread
On October 07, 1999 at 03:44:20, José Carlos wrote:
>On October 07, 1999 at 00:58:07, Christophe Theron wrote:
>
>>On October 06, 1999 at 21:52:28, Nicolas Carrasco wrote:
>>
>>>Now I am examining how my Alpha Beta cut off's are working!
>>>
>>>I would be extreamly pleased to know how many nodes your chess engine make at
>>>the initial position (if possible without move ordering) at the following
>>>depths:
>>
>>For Chess Tiger 12.0 (with move ordering and selection) the results are:
>>
>>2- 46
>>3- 606
>>4- 2088
>>5- 3929
>>6- 10102
>>7- 31441
>>
>>
>> Christophe
>
> This is a question I've been thinking of too. The results for my program are:
>
>2-87
>3-684
>4-3900
>5-17722
>6-82497
>7-511602
>
> As you can see, me search tree explodes! I use HT, killer heuristic, PVS, AS
>with a +-25 window, and I've experimented a lot with my move ordering. What else
>should I do to improve my nodes per ply? I know I'm missing: using HT for move
>ordering, null move, history heuristic...
> And I'm limiting the qsearch to avoid it takes too many nodes, that I think
>nobody does.
> What do you think I'm doing wrong?
>
> Thanks in advance,
>
> José C.
You are doing nothing wrong. The figures you give look like what I had with
Tiger before working hard on selectivity.
Generating and trying the HT move (if one is available) will help you a lot too.
Don't limit your QSearch. If the QSearch is well programmed, limiting it (in
depth) actually increases the tree size. My guess is that in chess extracting
the right information in all case is better than trying to extract less
information at any price.
A strange but in my opinion very important result to keep in mind.
Christophe
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