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Subject: Re: Branching factor again ;-)

Author: Andreas Guettinger

Date: 12:14:42 08/26/02

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On August 26, 2002 at 12:52:40, Steffen Basting wrote:

>Hello!
>Some days ago, I posted about the bad branching factor in my chess program.
>Here's the output of the starting position as an example:
>
>time depth      nodes           value   principal variation
>===============================================================================
>0       1       29              10      g1f3
>0       2       127             -6      b1c3 b8c6
>0       3       380             18      b1c3 b8c6 g1f3
>0       4       2141            0       b1c3 g8f6 g1f3 b8c6
>0       5       9174            16      b1c3 b8c6 g1f3 g8f6 e2e4
>1       6       54535           8       b1c3 d7d5 g1f3 b8c6 e2e4 g8f6
>7       7       408066          21      b1c3 d7d5 g1f3 d5d4 c3b5 b8c6 e2e4
>53      8       3220020         18      b1c3 c7c5 e2e4 b8c6 g1f3 e7e5 f1b5 g8e7
>
>3220020 nodes, 53 seconds: 59630 nodes/sec
>q-nodes: 2944182        evals: 2944182
>value: 18
>my move: b1c3
>principal variation: b1c3 c7c5 e2e4 b8c6 g1f3 e7e5 f1b5 g8e7
>

Well, first of all, you qnodes are much to high compared to the total nodes.
They should not mak more that about 50% of the total nodes in the starting
position, because there are no many captures possible. Do you make extensions in
the qnodes?

Here is the qnodes/nodes relation from my engine in the starting position:
Trying 60s
 1   0.00     10 :  d2d4 [21]
 2   0.00      0 :  d2d4 d7d5 [88]
 3   0.01     10 :  d2d4 d7d5 c1f4 [677]
 4   0.05      0 :  d2d4 d7d5 c1f4 c8f5 [3802]
 5   0.41      8 :  b1c3 e7e5 e2e4 f8c5 f1c4 [45680]
 6   2.96      2 :  e2e4 e7e5 g1f3 b8c6 f1b5 g8f6 [338313]
 7  15.33     10 :  e2e4 e7e5 f1c4 b8c6 g1f3 g8f6 b1c3 [2001916]


PV: 7 e2e4 e7e5 f1c4 b8c6 g1f3 g8f6 b1c3
bestmove = e2e4, score = 10, ply = 8/24, time =  60.36
nodes = 7065600, qnodes = 2877902[40.0%], NPS = 117kNPS

- Andy



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