5 men Syzygy on USB 3.0 Flash Drive

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matthewlai
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Re: 5 men Syzygy on USB 3.0 Flash Drive

Post by matthewlai »

syzygy wrote:
Norm Pollock wrote:When using tablebases. particularly large files, defragmenting them is important.
I wonder in what shape bittorrent typically leaves large downloaded files.
I would imagine as a large continuous piece.

All bittorrent clients I've used reserve space for the entire file once a file starts downloading, and just writes into position. So there's a lot of random write during download, but the file should be continuous afterwards.

The only advantage of not allocating all the space upfront is that it's possible to delay buying more capacity until downloads are underway. I don't think it really makes sense to optimize for that case to the detriment of the much more common case, and I don't think any bittorrent client does that.
Disclosure: I work for DeepMind on the AlphaZero project, but everything I say here is personal opinion and does not reflect the views of DeepMind / Alphabet.
Norm Pollock
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Re: 5 men Syzygy on USB 3.0 Flash Drive

Post by Norm Pollock »

With regard to "probe depth", Stockfish has a default of "1" whereas Fire, also using syzygy, sets it at "24". Houdini 1.5 using gtb, sets it in a range "16" to "24".

Since Stockfish just added syzygy recently, they probably did not tune the best setting for probe depth. I get better results playing blitz (1'+1") using "32" as my probe depth than using the default "1".
syzygy
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Re: 5 men Syzygy on USB 3.0 Flash Drive

Post by syzygy »

Norm Pollock wrote:With regard to "probe depth", Stockfish has a default of "1" whereas Fire, also using syzygy, sets it at "24". Houdini 1.5 using gtb, sets it in a range "16" to "24".

Since Stockfish just added syzygy recently, they probably did not tune the best setting for probe depth. I get better results playing blitz (1'+1") using "32" as my probe depth than using the default "1".
Assuming SyzygyProbeLimit is kept at 6, the value of SyzygyProbeDepth only matters when accessing 6-piece tables. (The n-piece tables for n < probelimit are accessed as if probedepth is 1. This is because they are assumed to fit in RAM.)

The optimal value for SyzygyProbeDepth will depend on available RAM and on whether the 6-piece WDL tables are accessed from HDD or from SSD. The only reason to increase it is to avoid excessive disk access which could lower nps in late middle game / early endgame.