Thursday, September 20, 2012

Perft for Checkers for Depth 27

With the new improvements in place, it would almost be a waste not to go deeper with my perft for checkers computation. Therefore, I computed perft(27) from the initial position of 8x8 checkers. Below you see the perft breakdown per move, called "divide". As stated before, these numbers were computed on a cluster of machines, further optimized with a "hard collision"-free transposition table as well as bulk counting. The move generator does not eliminate duplicate captures.

 move                 divide(27)
-------------------------------
 12-16    =  516399283859880203
 11-16    =  519502096014967805
 11-15    =  476666239516455180
 10-15    =  468705060101275533
 10-14    =  400425747281243848
  9-14    =  486493422418651579
   9-13    =  631652334435528457 
-------------------------------
perft(27) = 3499844183628002605

The implementation is "fault tolerant" against machine failures. Nevertheless, since I saw a few of these recoveries in this particular run, I may rerun this depth soon to verify the results pedantically.