Author: Larry Griffiths
Date: 17:28:28 02/01/01
Go up one level in this thread
On February 01, 2001 at 08:40:23, Severi Salminen wrote:
>>I would also like to know these things. It looks like my branching factor is
>>varying from 3 to 6 on average. Are these results for chess? Is it from the
>>initial board position?
>
>Yes, we are still talking about chess :) And we are talking about position after
>1.e4 e5 2.d4 d5 .The EBF depends a little on how you calculate it. My 3.6 is
>from:
>
>EMF=pow(leaf_nodes/legal_rootmoves, 1/(depth-1));
>
>If I use time for calculation my EBF from ply 8 to 9 is about 2.9. And you
>probably get similar results if you use the node count from successive plies.
>Could you post your numbers on this position also? I'll post mine tomorrow when
>I get to the right computer. Also indicate how you calculate EBF. (Effective
>Branching Factor)
>
>Severi
Using this position...
[D]rnbqkbnr/ppp2ppp/8/3pp3/3PP3/8/PPP2PPP/RNBQKBNR w KQkq d6 0 3
My program does not have code to setup the d6 en-passant square
so the totals below do not account for this...
I made 2 runs. Both runs use negamax with alpha/beta cutoffs
and 1 killer with interative deeping. The first run scores only material.
The second run always returns a score of zero. The BF column is a
branching factor that I calculate by dividing ply/moves by ply-1/moves.
BF does not use decimal points.
Leaf Effective Branching Factor is
Leafnodes/Rootnodes^1/(Depth-1)
TLeaf Effective Branching Factor is
Totalnodes/Rootnodes^1/(Depth-1)
I do not get smooth regular branching factors. They tend to be much
higher on even plys.
Elapsed Time= 85.56 seconds
Ply ---CAPTURES-- -----MOVES----- -----TOTAL----- BF
1 16 288 304 2
2 307 566 873 12
3 1,015 10,224 11,239 2
4 10,061 18,174 28,235 10
5 29,735 271,993 301,728 2
6 248,747 489,118 737,865 9
7 787,016 6,063,615 6,850,631 1
8 4,462,525 8,069,477 12,532,002 6
9 9,669,768 68,076,351 77,746,119 0
_____________ _______________ _______________
15,209,190 82,999,806 98,208,996
Captures/Moves Per Second= 1,147,797
Leaf Effective Branching Factor= 4.74
TLeaf Effective Branching Factor= 6.24
-----------------------------------------------------------------------
Elapsed Time= 43.16 seconds
Ply ---CAPTURES-- -----MOVES----- -----TOTAL----- BF
1 16 288 304 2
2 304 304 608 16
3 707 9,408 10,115 1
4 8,574 8,436 17,010 14
5 18,460 220,600 239,060 1
6 176,288 195,692 371,980 11
7 416,115 4,005,585 4,421,700 1
8 2,745,104 2,814,264 5,559,368 7
9 4,345,790 35,926,605 40,272,395 0
_____________ _______________ _______________
7,711,358 43,181,182 50,892,540
Captures/Moves Per Second= 1,179,269
Leaf Effective Branching Factor= 4.37
TLeaf Effective Branching Factor= 5.75
Larry.
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