I have the full 5 piece TBs on a fast USB flash drive and have previously confirmed this runs dramatically faster than my 7200 SATA drive.
I was expecting a measurable improvement for the higher TB usage however:
1024 games played 511:513 - the time control was CCRL 40/4 (this was 40/2 on my overclocked Quad)...
P.S. I will be running Rarely v No TB's soon...
Will you eventually try to test with some of the 6-piece tablebases? Any improvement would be noted more in this case.
I am not sure about the 6 piece TB's obviously flash memory is out of the question so you would need a fast raid array - also I have seen some very odd behaviour with part TB's but going for the full 6 men is 1.2TB download. I would need to know I would be getting a significant performance boost - which I doubt...
If you are really into difficult position analysis and finding the shortest mate then the TBs are usefull, but for me if it could have been mate in 10 but the computer took 12 moves I am not concerned.
Select or create some balanced early endgame positions. Not too simple, different from each other, and the more the better. Put them into a database and use this database as openings database. Play test matches with switching colors (=switching sides, 2 games per position), always versus the same good test opponent (maybe Zappa or whatever you have), oppo always in default engine settings... Or maybe it will be even better to set the opponent engine to NOT use tablebases, if possible, because Rybka's behaviour may influence also the other engine's tbs. access because sometimes more, sometimes less tbs. data will be in the windows file cache.
1. Rybka/no tbs.
(I suggest to set hash table and tbs. cache to 'medium' sizes, for that)
Oh and each of the position out of the book is played twice once for white and once for black.
I agree that a lot of the games will have been decided before TB's are accessed however I do not know of a suit of early endgame positions that I could just use and I would want it to be a little before any TB access occurs.
If anyone knows of such a suite please let me know...
Oh looking at Shredder it does seem to benefit from the Shredder bases
This is comparing the 'fast' Shredder bases to TB access on a fast 7200 SATA2 disk.
Now is this showing that the Shredder bases are helping or the TB's on disk are handicapping I am not sure - I suspect a bit of both but I will find out ;)
I have a version of Shredderbases in my programme, and the anecdotal evidence is that they definitely do make an ELO difference. At least 1 point per 100 games (which is usually the number of overnight games I look at per day). These games are at 2m+2s on a 3Ghz P4, and the lessened search time here might make a difference. (One of the most bizarre games was where Toga had BNPP vs BPPPP, my programme trades B for 2P, both programmes erroneously think the 4 pawns are better for a few moves, then Toga wipes out all four, but fiddles at mate-in-25 in KBN vs K for 50 moves). I will probably quantify the observed bitbase gain sometime next year.
This should certainly be a draw of course. After nearly 60 moves of shuffling, we get
Glaurung plays 108.. Rxd1?? 109 Kxd1 and #27
Glaurung plays 61.. Kc2?? 62 Kg4 b1Q 63 Rxb1 Kxb1 and #42
Glaurung plays 91.. Qe2?? 92 Qxe3+ and #27
This one also came up:
Bourzutschky and Konoval have solved such, but I don't think the TB is public. [Glaurung ended up winning here - my programme had a slight logic error in aiming for this position; it knows that RmP vs Rm is likely drawn due to trading the minor piece for the pawn, but I didn't think to note that BBP vs NN is not the same].
As I watched the match it bounced about a little at the beginning but then stayed fairly even for the last few hundred games...
I tended to check the score a couple of times a day over the 4 days for the test.
Rybka doesn't win KBNK and KNNKP without TBs. KQPPKQ is difficult, too.
I made some tests about TBs as i like that stuff very much. I was very disappointed about my results, TBs only added ~5 Elos for 5 man on a SSD.
And i saw Rybka win some games without TBs that i think are difficult to win - like KQKR.
The tablebases for both engines definitely made differences in the Mexico match--noticeable differences just in ten games--this tends to happen more often at the highest levels and in longer games.
I am not shure, if the effect is better in longer games. But I'd like to hear some arguments pro and con.
In the Mexico match i had a good set of TBs - all 5 man and 54 GB of 6 man (incl. KRPKNP - the missing TB in Amsterdam).
I didn't have KRRBKQ (and i still haven't got it). Maybe that one could have save Rybka from loosing - but i don't think so.
I use 16 MB for TB cache and a SSD with 0.1 ms of access time.
With this setup, I don't see any slowdown (with an ordinary hd you can see this slowdown when looking at the Task Manager - with a 7200 rpm disk, cpu usage goes down significantly when TBs are used - with that SSD cpu usage is always at 100%).
So i think, my results should be better when using TBs. But they aren't.
I'll make more tests about this, but i don't know if the money spent for these SSDs was a good investment.
5 Elo is nothing to scoff at. Somewhere down the line, that will be the difference between winning and not winning.
> 5 Elo is nothing to scoff at
Doesn't sound like much at first, but it's probably equivalent to five weeks or so of either yours or Larry's time!
Any comments. These gains were in blitz games of 5 minutes each side
Dr. Peter arvalho
For example, if you analyse a five piece position in Fritz, AND you have the complete five piece tablebases, the GUI will simply show the list of all legal moves and their evals from the tbs., each - most of the time, there seem to be rare exceptions where the engine will still calculate although the tablebase for the position is available (at least I noticed that in Fritz 8's GUI; not sure about newer ones).
Watch this space
Over time as processor improvements have dramatically out paced HD improvements the benefit of TBs will have decreased (or at least that is the theory I believe).
There was a movement (led by Bruce Moreland, writer of Ferret, which was 2nd place in the WCCC/WMCCC a few times) at one point (seems to be from 2000) to allow only Nalimov (or only one entrant, named by him, for a given tournament) to use his TBs.
>Personally I think that Nalimov should be allowed to designate one program as"his", at which point he'd become a co-author of that program, and nobody could use the tables in official competition except that program.
His position did not gain much support. :)
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