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Subject: Re: Strange behaviour of my new engine

Author: Steffen Basting

Date: 09:54:03 08/01/04

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Hi Gerd!

Thanks for replying!

>Mate in 4 should be independent from search depth.
>Isn't the game over after Rh8#?

Yes, of course :-)

>Seems that you don't terminate your PVs correctly.

I've just fixed this. It now says:
0.00s   1=      315        187    f4f1
0.00s   2=      1926       148    f4f1 d7c7
0.04s   3=      23053      131    f4f2 e6g4 e1e8 a8e8 d4a7
0.20s   4=      93395      89     e1d1 f7f6 g5h4 a8c8
0.87s   5=      515342     97     f4f1 f7f6 g5f4 e6f5 e1c1
2.48s   6=      1452346    68     f4f1 e6f5 c2c3 e8e1 f1e1 a8e8 e1d1 e8e2
6.68s   7=      4129525    70     f4f2 e6g4 e1f1 f7f6 g5f4 d7e6 f4c7
8.57s   8=      5185655    120    f4f2 e6g4 e1f1 f7f6 g5f4 g6g5 f4d6 d7d6
8.58s   8+      5195575    370    f4f2 e6g4 e1f1 f7f6 g5f4 g6g5 f4d6 d7d6
8.60s   8+      5205409    870    f4f2 e6g4 e1f1 f7f6 g5f4 g6g5 f4d6 d7d6
8.73s   8++     5296335    #4     d4g7 g8g7 g5f6 g7g8 f4h4 e6f5 h4h8 #
9.09s   9=      5529524    #4     d4g7 g8g7 g5f6 g7g8 f4h4 e6f5 h4h8 #
9.64s   10=     5896253    #4     d4g7 g8g7 g5f6 g7g8 f4h4 e6f5 h4h8 #
11.86s  11=     7560467    #4     d4g7 g8g7 g5f6 g7g8 f4h4 e6f5 h4h8 #
19.04s  12=     12961258           #4     d4g7 g8g7 g5f6 g7g8 f4h4 e6f5 h4h8 #
34.34s  13=     23696937           #4     d4g7 g8g7 g5f6 g7g8 f4h4 e6f5 h4h8 #

>How to translate your mate scores?

When a mate occurs, I return 20000+depth so that "short" mates are preferred.
But you were right, I forgot to set the counter to 0 then, this caused those
strange lines.

>1.bugs

Yeah, there are probably plenty of them :-)

>2.better eval

Does eval have such a positive effect on depth / node ratio?

>3.carefull with R==3 near the leaves, checks in qsearch?

Yes, R=3 seems to be dangerous sometimes. I now use R=2 when the depth is
low. I don't use checks in qsearch (yet)...

>4.SEE or more sophisticated move ordering, checks, putting pieces enprise,
>  at interior nodes one may use more expensive move scoring/sorting.
>5.hashing score and bounds or flags as well.
>6.fractional extension/reductions.
>7.tuning.

4-7 will be done after I've finished with 1 ;-)

Thanks again,
Steffen




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