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Subject: Re: What is the branching factor for this position?

Author: leonid

Date: 02:57:22 08/11/00

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On August 11, 2000 at 00:02:39, Larry Griffiths wrote:

>Leonid,
>
>I am wondering now if I am confusing BruteForce with Minmax.  I always thought
>BruteForce was generating ALL the moves (or another name for MinMax).

It could be that I am confused with name. It happen to me often. Never mind.
Will just say what I see as Brute Force. Brute Force look all the possibility in
given position before it reach its decision. It is not forced to see all the
moves in each ply for doing so. In MiniMax you see all moves (nodes) for each
ply before saying your result.


>Anyway, I ran your position to 6 plys and here are the results...

Some data still is useful for me even if I am doubious about my Brute Force
branching factor.

>
>TCBoard - RunMinMax()
>
>Elapsed Time= 1125.38 seconds
>
>Ply ---CAPTURES-- -----MOVES----- -----TOTAL----- ---Invalid---
>  1             5              30              35             2
>  2           130           1,065           1,195            93
>  3         6,613          35,468          42,081         2,107
>  4       199,119       1,282,187       1,481,306       107,805
>  5     8,725,158      43,530,271      52,255,429     2,555,427
>  6   281,688,872   1,585,505,759   1,867,194,631   132,999,965
>    _____________ _______________ _______________ _____________
>      290,619,897   1,630,354,780   1,920,974,677   135,665,399
>
>        Captures/Moves Per Second=      1,706,964


What is interesting for me in your table is the "INVALID" number. Probably you
generate invalid move in move generator and only lately you see if it is legal.

Must I understand Capture/Moves as simply "illegal moves generated by second"?
And is this number 1 707 964? And on what computer?

>The branching factor looks like it is between 35 and 36 using MinMax.
>This is what I have found to be documented for the average number of moves
>for a side.

For this I have special fonction in my program. It do usual search by Brute
Force but only generate for each ply all its legal moves. This permit constant
saying of average moves for given position. Have this for 8 and 10 plys deep
search.

Thanks for response,
Leonid.

>Larry.



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