In an old thread about
rectangular boards, I gave the perft(9) result for 12x10 boards. Together with the 10x12 board with the right coloring, this is the largest board for which a bit-layout using 1 ghost column at each side fits within a 64-bit integer. The 10x12 board has the following bit-layout:
Code:
0 1 2 3 4 5
6 7 8 9 10 11
13 14 15 16 17 18
19 20 21 22 23 24
26 27 28 29 30 31
32 33 34 35 36 37
39 40 41 42 43 44
45 46 47 48 49 50
52 53 54 55 56 57
58 59 60 61 62 63
Below the results of a perft(10) for the initial position on the 10x12 board
Code:
b b b b b b
b b b b b b
b b b b b b
b b b b b b
. . . . . .
. . . . . .
w w w w w w
w w w w w w
w w w w w w
w w w w w w
"W:B1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24:W37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60"
Searching to nominal depth=10
info depth 1 leafs 11 nodes 1 time 0 nps inf
info depth 2 leafs 121 nodes 12 time 0 nps inf
info depth 3 leafs 1222 nodes 133 time 0 nps inf
info depth 4 leafs 10053 nodes 1355 time 0 nps inf
info depth 5 leafs 79049 nodes 11408 time 0 nps inf
info depth 6 leafs 584100 nodes 90457 time 7 nps 12922429
info depth 7 leafs 4369366 nodes 674557 time 59 nps 11433169
info depth 8 leafs 31839056 nodes 5043923 time 468 nps 10777613
info depth 9 leafs 236364607 nodes 36882979 time 3327 nps 11085957
info depth 10 leafs 1742748504 nodes 273247586 time 24717 nps 11055047
The straightforward bit-layout for the 12x10 board has 1 ghost column at each side along the longer column dimension and requires 65 bits. Fortunately, a rotation of the internal bit representation by 90 degrees will align the ghost squares along the shorter row dimension. As I showed 3 years ago, this makes it possible to also fit a 12x10 board inside a 64-bits integer:
Code:
58 45 32 19 6
52 39 26 13 0
59 46 33 20 7
53 40 27 14 1
60 47 34 21 8
54 41 28 15 2
61 48 35 22 9
55 42 29 16 3
62 49 36 23 10
56 43 30 17 4
63 50 37 24 11
57 44 31 18 5
Below the results of a perft(11) for the initial position on the 12x10 board
Code:
b b b b b
b b b b b
b b b b b
b b b b b
b b b b b
. . . . .
. . . . .
w w w w w
w w w w w
w w w w w
w w w w w
w w w w w
"W:B10,20,5,15,25,9,19,4,14,24,8,18,3,13,23,7,17,2,12,22,6,16,1,11,21:W40,50,60,45,55,39,49,59,44,54,38,48,58,43,53,37,47,57,42,52,36,46,56,41,51"
Searching to nominal depth=11
info depth 1 leafs 9 nodes 1 time 0 nps inf
info depth 2 leafs 81 nodes 10 time 0 nps inf
info depth 3 leafs 658 nodes 91 time 0 nps inf
info depth 4 leafs 4265 nodes 749 time 0 nps inf
info depth 5 leafs 27117 nodes 5014 time 0 nps inf
info depth 6 leafs 167140 nodes 32131 time 2 nps 16065500
info depth 7 leafs 1049442 nodes 199271 time 17 nps 11721824
info depth 8 leafs 6483961 nodes 1248713 time 113 nps 11050558
info depth 9 leafs 41291394 nodes 7732674 time 748 nps 10337799
info depth 10 leafs 263895730 nodes 49024068 time 4633 nps 10581495
info depth 11 leafs 1731541289 nodes 312919798 time 28484 nps 10985810
And yes, the results up to and including depth=9, match the results that I gave 3 years ago.