Code: Select all
fen rnb1kbnr/pp1pp1pp/1qp2p2/8/Q1P5/N7/PP1PPPPP/1RB1KBNR b Kkq - 2 4
OK
perftfastmt 7
Time elapsed: 51.66800 seconds
Total leaf nodes: 14794751816
286.3M LNPS
Moderators: hgm, Rebel, chrisw
Code: Select all
fen rnb1kbnr/pp1pp1pp/1qp2p2/8/Q1P5/N7/PP1PPPPP/1RB1KBNR b Kkq - 2 4
OK
perftfastmt 7
Time elapsed: 51.66800 seconds
Total leaf nodes: 14794751816
286.3M LNPS
It appears that the correct answer is indeed 14,794,751,816. Symbolic calculates the sum in three different ways, and that's the answer it gets, too. The alternative answer of 14,794,762,630 is from Ankan's GPU program -- which may be based on gperft -- and the difference is surely due to a false positive transposition table probe.sje wrote:Three in agreement, so far
A third program also says: 14,794,751,816
BUT
A fourth program says: 14,794,762,630
I'll guess that the other mis-matched counts in the 409 work unit result are all derived from just one or two false positives which were retained in the transposition table for the duration of the run.ankan wrote:yes, most likely due to false positive from transposition table probe.
Just tried with non hash versions of the program and got correct answer:
CPU Perft 7: 14794751816, Time taken: 73.9707 seconds, nps: 200008156
GPU Perft 7: 14794751816, Time taken: 0.526672 seconds, nps: 28091023117
Code: Select all
Intel Pentium D930 (3 GHz).
JetChess 1.0.0.0 (single core, 32-bit, hash = 512 MB).
rnb1kbnr/pp1pp1pp/1qp2p2/8/Q1P5/N7/PP1PPPPP/1RB1KBNR b Kkq - 2 4
1 qb6-a5 458387356
2 qb6-c5 651144888
3 qb6-d4 730695681
4 qb6-e3 739871066
5 qb6*f2 25924489
6 qb6-c7 481112000
7 qb6-d8 265137487
8 qb6-b5 569536792
9 qb6-b4 460349749
10 qb6-b3 548033029
11 qb6*b2 685709017
12 qb6-a6 271118692
13 nb8-a6 513657072
14 ng8-h6 589352355
15 c6-c5 360968765
16 f6-f5 531397121
17 a7-a6 423681823
18 a7-a5 447089524
19 d7-d6 703673629
20 d7-d5 827346268
21 e7-e6 759858285
22 e7-e5 739884888
23 g7-g6 538145267
24 g7-g5 525444540
25 h7-h6 437638427
26 h7-h5 541275720
27 ke8-d8 439181982
28 ke8-f7 529135904
Total: 14794751816
14,794,751,816 (move pathes after 7 half moves).
Time: 37.281 s (0:00:37.281).
Code: Select all
iCE 3.0 v658 x64/popcnt [2016.1.3]
position fen rnb1kbnr/pp1pp1pp/1qp2p2/8/Q1P5/N7/PP1PPPPP/1RB1KBNR b Kkq - 2 4
perft 7
perft Nodes Time
1 28 0 sec
2 741 0 sec
3 21.395 0 sec
4 583.456 0.016 sec
5 17.251.342 0.171 sec
6 490.103.130 4.493 sec
7 14.794.751.816 134.067 sec
Perft 1 - 7 executed in 138.747 sec (110.29 Mnps)
Code: Select all
ply: 1 nodes: 28 promotions: 0 castling: 0
ply: 2 nodes: 741 promotions: 0 castling: 0
ply: 3 nodes: 21395 promotions: 0 castling: 0
ply: 4 nodes: 583456 promotions: 0 castling: 0
ply: 5 nodes: 17251342 promotions: 0 castling: 0
ply: 6 nodes: 490103130 promotions: 0 castling: 36
ply: 7 ndoes: 14794751816 promotions: 0 castling: 1719609