Dann Corbit wrote: ↑Fri Mar 27, 2020 5:11 am
Ovyron wrote: ↑Fri Mar 27, 2020 3:36 am
Ha, the funny thing is that mass storage isn't even needed, Bernstein Learning shows how little the engine needs to save in a file for it to work. We're talking about 64MB per year or something even storage from 10 years ago could manage without sweating.
Hyatt beat him to it, and the main problem is it doesn't really work. By that I mean in a real chess game, unplayed moves happen pretty soon and then you are back to square zero, and not only that you don't have as much spiffy stuff stored in the hash because you have not been analyzing as much, with all those special deep cutoffs in the hash.
If the point of it is to save time it clearly does work. The retrieval times, assuming the stored positions are NOT in memory, can be less than 1ms. With them in memory at the start of the game your talking micro-seconds. Even fast games in a testing framework aren't so fast that positions stored on disk wouldn't be of benefit.
While it may be true that the the engine will see positions not in the position memory that's not the same as “being back to square zero”. It's very likely that the stored positions are much better than something that could be calculated in the short time available for a given move. This means avoiding past inaccuracies and mistakes.
It takes most engine a while to calculate an accurate move. If this has already been done in a previous encounter and the amount of time available to make a move is the same (or less) then it makes sense to use the stored data. If the amount of time available to make the move is much greater than the time it took to calculate the stored move then it makes sense to calculate a new move, make it across the board and then store the new results.
When you reach a position not stored there is plenty of time for the engine to fill the TT with positions that are much more relevant to the current position than if you had expended this time calculating several past moves from scratch.
In short, I don't buy the “it doesn't work” routine. It may not be a panacea but it's definitely useful. I personally don't use this method due to a lack of a “good” engine that supports it. I haven't purchased an engine in many years. I think ChessMaster series was the last time I forked over money for an engine (27 years ago?). I could be persuaded to buy an engine like Houdini or Komodo were they to offer a robust version of this that had a published position format that anyone could use/and or program to. I figure the open format would gain more support than a proprietary approach and more engines would eventually support it.
Regards,
Zenmastur
Only 2 defining forces have ever offered to die for you.....Jesus Christ and the American Soldier. One died for your soul, the other for your freedom.