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Subject: Re: Averaged results.

Author: Dan Andersson

Date: 13:04:27 04/03/04

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On April 02, 2004 at 20:39:38, Dann Corbit wrote:

>On March 31, 2004 at 21:43:09, Dan Andersson wrote:
>
>>Averaged results over 1000 runs per depth:
>>value    depth   nodes      relative minimax    relative a-b
>>2        2       3.463      0.86575             1.1543333333333
>>10       4       10.399     0.6499375           1.4855714285714
>>42       6       28.148     0.4398125           1.8765333333333
>>170      8       74.578     0.2913203125        2.4057419354839
>>682      10      185.363    0.1810185546875     2.9422698412698
>>2730     12      459.625    0.11221313476563    3.619094488189
>>10922    14      1106.041   0.067507385253906   4.3374156862745
>>43690    16      2691.694   0.041071990966797   5.2675029354207
>>174762   18      6280.954   0.023959938049316   6.1397399804497
>>699050   20      14867.996  0.014179225921631   7.2633102100635
>>2796202  22      34813.976  0.0083002986907959  8.5015814407814
>>11184810 24      80965.644  0.0048259284496307  9.8847080942498
>>44739242 26      185048.509 0.0027574376612902  11.295154062138
>
>I am guessing this is what the table means:
>value = the number of nodes in the full tree
>depth = search depth
>nodes = nodes examined by alphabeta (but then the depth=2 makes no sense)
>relative minimax = ratio of nodes examined compared to minimax
>
>relative a-b I do not understand.
>
>Can you explain to greater detail what this represents?

The program is a representation of A-B search of a simple game where the two
players alternate in appending a trailing digit to a binary number to an even
depth. Trivial but essentially representing the minimal game.
And Nodes is the number of leaf-nodes searched by an algorithm with a random
move ordering in that tree.
 Value is the result of the search. It will never vary under the current
distribution function (It's easy to create a pseudo-random sequence) as it is
the fixed sequence 0..2^d-1. Where the value of a leaf-node is the binary
representation of the sequence of moves through the tree. And its value is the
value of a binary string '10' repeated d/2 times.
 Depth is searched depth.
 Nodes should really be leaf-nodes.
 Relative minimax is the quotient of the value Nodes to the number of leaf-nodes
searched by minimax.
 Relative A-B is the quotient of the value Nodes to the number of leaf-nodes
searched by a perfect alpha-beta search.

MvH Dan Andersson



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