Java perft, again

After some more optimizations my Java perft now runs much faster than before, it is now nearly half as fast as the C code. I would have expected much less from Java and am pleasantly surprised. I'm quite happy already with the Java engine, so now for the hard part - creating an interface....

perft 1 time 1 positions 7 kN/s 7
perft 2 time 1 positions 49 kN/s 49
perft 3 time 1 positions 302 kN/s 302
perft 4 time 1 positions 1469 kN/s 1469
perft 5 time 1 positions 7361 kN/s 7361
perft 6 time 15 positions 36768 kN/s 2451
perft 7 time 1 positions 179740 kN/s 179740
perft 8 time 63 positions 845931 kN/s 13427
perft 9 time 250 positions 3963680 kN/s 15854
perft 10 time 1156 positions 18391564 kN/s 15909
perft 11 time 5437 positions 85242128 kN/s 15678
perft 12 time 24954 positions 388623673 kN/s 15573

Java perft

I just finished debugging a Java checkers move generator - thanks to perft I found some bugs, and just watched the first game of my Java checkers engine played against itself (not a nice sight). Not surprisingly (at least to me), the Java code runs much slower than the C code - I found a factor 3.2 difference. Is that just me, or is it Java??

C (Cake's code without move ordering)
depth 1 positions 7 time 0.000000 1.$ kN/s
depth 2 positions 49 time 0.000000 1.$ kN/s
depth 3 positions 302 time 0.000000 1.$ kN/s
depth 4 positions 1469 time 0.015000 97.9 kN/s
depth 5 positions 7361 time 0.000000 1.$ kN/s
depth 6 positions 36768 time 0.000000 1.$ kN/s
depth 7 positions 179740 time 0.000000 1.$ kN/s
depth 8 positions 845931 time 0.063000 13427.5 kN/s
depth 9 positions 3963680 time 0.156000 25408.2 kN/s
depth 10 positions 18391564 time 0.547000 33622.6 kN/s
depth 11 positions 85242128 time 2.656000 32094.2 kN/s
depth 12 positions 388623673 time 12.266000 31683.0 kN/s

Java
perft 1:7 1ms 7000positions/sec
perft 2:49 1ms 49000positions/sec
perft 3:302 1ms 302000positions/sec
perft 4:1469 17ms 86000positions/sec
perft 5:7361 1ms 7361000positions/sec
perft 6:36768 16ms 2298000positions/sec
perft 7:179740 17ms 10572000positions/sec
perft 8:845931 79ms 10707000positions/sec
perft 9:3963680 392ms 10111000positions/sec
perft 10:18391564 1813ms 10144000positions/sec
perft 11:85242128 8486ms 10045000positions/sec
perft 12:388623673 39141ms 9928000positions/sec

A postscript a couple of days later: I managed to improve my Java code a bit, it is now only 2.3 times slower than the C code. I suppose that is about the best one can hope for with Java - or??

perft for checkers

A couple of days ago I got a mail from Aart Bik, a programmer working at Google. He is currently developing a checkers application (among others) for the Google android platform (aka gPhone). He asked me about perft numbers for checkers. Perft is an invention of the chess programming community, a test to verify the correctness of the move generator, by printing how many legal moves exist in a search tree to depth N from the current position. Although I have this function in my chess engine, I never thought of adding it to Cake until now. However, Aart is right, and a perft function is always good to have for debugging purposes, so I added it to Cake. In the next CheckerBoard/Cake release, Cake will have this functionality. For starters, here are the numbers Cake reports from the initial position:

depth 1 positions 7
depth 2 positions 49
depth 3 positions 302
depth 4 positions 1469
depth 5 positions 7361
depth 6 positions 36768
depth 7 positions 179740
depth 8 positions 845931
depth 9 positions 3963680
depth 10 positions 18391564
depth 11 positions 85242128
depth 12 positions 388623673

Aart is happy too, since his numbers match. If you are interested in his applications for the gPhone, then check out his blog.