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==Hashing==
Perft can receive another speed boost by [[Hash Table|hashing]] node counts, with a small chance for inaccurate results. Sometimes this is used as a sanity check to make sure the hash table and keys are working correctly.
=Divide=
The Divide command is often implemented as a variation of perft, listing all moves and for each move, the perft of the decremented depth. However, some programs already give "divided" output for perft.
<span id="History"></span>
In '''August 2017''', [[Ankan Banerjee]], who already confirmed Peter Österlund's perft('''14''') in September 2016 <ref>[http://www.talkchess.com/forum/viewtopic.php?t=61119&start=30 Re: yet another attempt on Perft(14)] by [[Ankan Banerjee]], [[CCC]], September 09, 2016</ref>, computed perft('''15''') of 2,015,099,950,053,364,471,960 with his [[GPU]] perft program <ref>[https://github.com/ankan-ban/perft_gpu ankan-ban/perft_gpu · GitHub]</ref>, running it several days two times with different [[Zobrist Hashing|zobrist keys]] on a cluster of [https://en.wikipedia.org/wiki/Nvidia_DGX-1 Nvidia DGX-1] server systems <ref>[https://www.nvidia.com/en-us/data-center/dgx-1/ DGX-1 for AI Research | NVIDIA]</ref>. His program starts exploring the tree in [[Depth-First|depth first]] manner on CPU. When a certain depth is reached a GPU function (kernel) is launched to compute perft of the subtree in [[Best-First|breadth first]] manner <ref>[http://www.talkchess.com/forum/viewtopic.php?t=64983&start=9 Re: Perft(15): comparison of estimates with Ankan's result] by [[Ankan Banerjee]], [[CCC]], August 26, 2017</ref>. Ankan Banerjee dedicated his computations in honor to [[Steven Edwards]] - whose tireless efforts for verifying perft(14) encouraged him to verify perft(14) and take up the challenge to compute perft(15) <ref>[http://www.talkchess.com/forum/viewtopic.php?t=64983&start=4 Re: perft(15)] by [[Ankan Banerjee]], [[CCC]], August 25, 2017</ref>.
<span id="Divide"></span>
=Results=
