Author: Renze Steenhuisen
Date: 08:44:26 04/07/04
Go up one level in this thread
>>>>>>How important is it to hash in the castling rights and en-passant fields?
>>>>>
>>>>>Very important; it will go wrong at a tournament otherwise.
>>>>
>>>>Yes, I read of some (your?) tournament issue?
>>>>
>>>>But is it important for my results, now? Because I am using the starting
>>>>position as test position...
>>>
>>>If you search above a ply or 4 sure, as then you can already start capturing en
>>>passant.
>>
>>Should I put it in first, could that really be the problem?
>
>Depends upon how you measures errors/collissions.
>Define collision first.
>
>(1) two different positions produce the same hash signature...
>
>(2) two different hash signatures address the same table entry...
>
>(1) should not happen with 64 bit signatures. (2) is common and is why the
>replacement strategy is so important.
I defined collision somewhere in this thread but it is the same as (1):
from code of DarkSight which is comparable with next.c in Crafty
/********************/
case HASH_MOVE:
if( a tt_move is provided )
{
tree->stats.hashkey_requests++;
if( provided tt_move is valid move )
return tt_move;
else
tree->stats.hashkey_collisions++;
}
/********************/
When I search from the starting position I get:
tree->stats.hashkey_collisions = 34
tree->stats.hashkey_requests = 38503
Or to give the complete output...
nodes searched-> 4651507
qnodes/nodes_searched-> 0.24
capture moves-> 0
evaluations done-> 4150454
first fail highs-> 220020
fail highs-> 257405
move-ordering: 85.48
NULL-move fail-highs-> 903676
tt_probes-> 1367771
tt_hits-> 139286
tt hit-ratio: 10.18
TT overwrites-> 87645
number of LOWERbounds-> 257405
number of EXACTbounds-> 499
number of UPPERbounds-> 115898
hashkey collisions: 34 / 38503 = (0.0009)
ptt_probes-> 4150454
ptt_hits-> 3627474
ptt hit-ratio: 87.40
PTT overwrites-> 481427
PTT key collisions-> 82819
Futility Prunings-> 287703
EXTENSIONS:
Check Ext: 39065
Mate Threat Ext: 27
Single Reply Ext: 0
Pushed Pawn Ext: 1086
Recapture Ext: 31824
Singular Ext: 0
captures: 374765
normals : 228993
norm/caps: 0.61
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Last modified: Thu, 15 Apr 21 08:11:13 -0700
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