Author: Michel Langeveld
Date: 14:01:34 12/01/04
Go up one level in this thread
Is it a lot more nodes ... or just a few more nodes?
Here is a 11 ply search with TSCPGothic (compiled for normal chess):
I think they should be close. I saw examples where with repition on, it
generates a bit more nodes. I tried 2 positions, and it were all a bit less.
[D]r1bqkbnr/pppp1ppp/2n5/1B2p3/4P3/5N2/PPPP1PPP/RNBQK2R b KQkq -
repetition off:
11* 1212 13030193 16 e2e4 d7d5 e4d5 d8d5 g1f3 c8f5 b1c3 d5d6 f1c4 d6c5 d
2d3
repetition on:
11* 1229 12998060 16 e2e4 d7d5 e4d5 d8d5 g1f3 c8f5 b1c3 d5d6 f1c4 d6c5 d
2d3
conclusion: a few less nodes
[D]r1bqkbnr/pppp1ppp/2n5/1B2p3/4P3/5N2/PPPP1PPP/RNBQK2R b KQkq -
repetition off:
12* 6039 64176797 -9 g8f6 e1g1 f8c5 d1e2 e8g8 b1c3 f6g4 c3d1 a7a6 b5c4 d
8f6 g1h1
repetition on:
12* 6101 63430117 -9 g8f6 e1g1 f8c5 d1e2 e8g8 b1c3 f6g4 c3d1 a7a6 b5c4 d
8f6 g1h1
conclusion: a few less nodes
[D]r5k1/1n3p1p/1PN1p1p1/8/p7/4P2P/6PK/3R4 w - -
repetition off:
12* 2060 26034077 -60 d1d7 a4a3 d7b7 a3a2 b7c7 a2a1q b6b7 g8g7 c7c8 a8c8
b7c8q a1e1 c8d7 e1e3
repetition on:
12* 2356 29480990 -60 d1d7 a4a3 d7b7 a3a2 b7c7 g8g7 b6b7 a2a1q c7c8 a8c8
b7c8q a1e1 c8d7 e1e3
conclusion: a few _more_ nodes
I don't mind to try more positions if you want.
This is what I use in TSCPGothic for repetition check:
/* reps() returns the number of times the current position
has been repeated. It compares the current value of hash
to previous values. */
int reps(void)
{
int i;
int r = 0;
for (i = hply - fifty; i < hply; ++i)
if (hist_dat[i].hash == dynhash)
++r;
return r;
}
Let me know if you can optimize this even more further.
In search I do:
check first reps,
then lookup hash,
the quiescense search,
then nullmove,
then generation of moves,
then score them,
then play them with selectsort,
then I check for mate/stalemate
then I check for fifty moves in a row,
then I store end
return function
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