Author: Robert Hyatt
Date: 11:56:12 07/21/02
Go up one level in this thread
On July 21, 2002 at 14:54:18, Robert Hyatt wrote: >On July 21, 2002 at 01:29:38, Uri Blass wrote: > >>On July 20, 2002 at 22:20:29, Robert Hyatt wrote: >> >>>On July 20, 2002 at 05:55:43, Uri Blass wrote: >>> >>>>On July 20, 2002 at 05:47:38, Gian-Carlo Pascutto wrote: >>>> >>>>>On July 20, 2002 at 02:52:11, Uri Blass wrote: >>>>> >>>>>>My question was not about comparing using hash tables >>>>>>and not using hash tables but about comparing using hash tables >>>>>>in the normal way and using hash tables >>>>>>for all purposes except pruning. >>>>> >>>>>In the example given, the move ordering from hashtable is almost >>>>>irrelevant, so all the gains are due to pruning. >>>>> >>>>>-- >>>>>GCP >>>> >>>>I did not ask about single example from endgame but about >>>>the middle game or about rating improvement. >>>> >>>>Uri >>> >>> >>>I gave you an answer of sorts. Best case is fine 70. 3x as many plies. >>>Middlegame seems to be a factor of 2x in terms of time to reaching a specific >>>depth. So a fraction of a ply. So from early middlegame to endgame sees this >>>go from a fraction of a ply to (say) 30 additional plies... >>> >>>The 30 is important. It doesn't just happen in fine 70. It happens in lots >>>of important king and pawn endings. >> >>I know that in simple endgames you can get big improvement thanks to using hash >>tables for pruning. >> >>I also know that you can get a factor of 2 in the middle game from hash tables >>when the comparison is between using hash tables and not using them. >> >>It did not answer my questions. >> >>Only Christophe answered them when he explained that I may get 10% speed >>improvement in the middle game from pruning. >> >>Uri > >OK... I will take my usual approach and simply give you _real_ data. > >Three positions. The first tactical, the second just a middlegame position >with no real tactics, the last an endgame (fine70). All three searched with >normal hashing, and then using hashing as normal, but not allowing the hash >stuff to produce a fail high, fail low, or exact score. It can still tell me >to avoid a null-move search. The difference in times, then, is _totally_ >dependent on using the hash scores only, as everything else is identical. > > > hashon hashoff >Tactical 48 secs 78 secs >normal 118 secs 183 secs >fine 70 0 secs 58 secs > >In fine 70, both searched to 18 plies. hash on got right move (kb1 >winning a pawn). hash off did not get right move. > >You can draw your own conclusions. 10% is obviously _way_ too low. I >said roughly a factor of two, for middlegames, which is pretty close in >the first two. In the last position we _know_ what hashing does. > I should add, if you _really_ don't think that I answered your question, then maybe the question you actually _asked_ and the question you _meant_ to ask are not the same thing. I believe my previous post shows that I _did_ directly answer the question you asked. _exactly_...
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