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descriptionPOLL:Which Hashtable is better ? EmptyPOLL:Which Hashtable is better ?

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Hello Friends,

For more Information:
http://www.sedatcanbaz.com/chess/512mb128mb/

Thanks in advance,
Sedat Canbaz

descriptionPOLL:Which Hashtable is better ? EmptyRe: POLL:Which Hashtable is better ?

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I have chose 512 MB.
I play on ChessBase for 2 years already with 512 MB Hush at 3+0min-5+0min Blitzgames.
At 16+0 min or more Timefactor i use 1024 MB !

we have with the i7 980X a strong CPU !
and i remember very well the words from Lukas Cimiotti (Victor Kullberg)

He say:
the stronger is your cpu they can use more hush !

descriptionPOLL:Which Hashtable is better ? EmptyRe: POLL:Which Hashtable is better ?

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I thought the most the better, but to make sure, i made a tournament for 40/40 with 128, 256,512 and 1024 hash and the best result came from 256 !

descriptionPOLL:Which Hashtable is better ? Emptyre

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Clever, I thought about it ....... I have made ​​the tournament splith depth (10-12-14-16-18) how to play the game cycle that the results were real? Is not a little 20-cycle? How long does it game? thank you

descriptionPOLL:Which Hashtable is better ? EmptyRe: POLL:Which Hashtable is better ?

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@fescoto wrote:
I thought the most the better, but to make sure, i made a tournament for 40/40 with 128, 256,512 and 1024 hash and the best result came from 256 !


For right now,the current votes are showing that 512 mb hashtable size is better on i7 980X cores

Actually 128 mb hashtable's performance (for blitz games) is better on my quads

As we see the current match results are still not very clear about which is better
In my opinion for under these conditions,the both hashtable size are very close in strength

And as i mentioned before,to be 100 % sure we need at least 1000 games per player

Note also that opening book is playing a big role about the elo strength of the participants
Thats why i have tested the both hashtables with a neutral opening book (up to 8 moves) and with alternate colors

Maybe later (after SCCT Super League) i will resume the hashtable test and i will run min 1000 games

Best,
Sedat

descriptionPOLL:Which Hashtable is better ? Emptyre

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Does not need to increase the Cache Engine Tablebases / Fritz GUI options in GUI? Or is Tablebases Cache Engine / GUI constant in relation to the board Hasch Table Engine?


Thank you for your answers

descriptionPOLL:Which Hashtable is better ? EmptyRe: POLL:Which Hashtable is better ?

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I'd think 512mb would be on the large size for a 3m game. I generally stick with 128mb for 1-2 minute games, 192mb for 3-5 minute games, and 256mb for 5-9 minute games. 10+ gets 512+

Would be interesting to see if we got outside of the standard deviations on any of the settings, would definitely change the way I run my tournaments.

descriptionPOLL:Which Hashtable is better ? Emptycalculating proper hash size

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Hi Elric (or Ward?)-
yes, absolutely...
optimal hash size is directly proportional to the specific time control being used
(and the speed of the system)

here's a formula which I use that may be of interest...and my short explanation

if given several pieces of information (nodes per second, time per move, and hash table entry size),
an optimal hash size (amount of memory allocated for the hash table) for can be calculated

time per move (secs) * nodes per sec * hash entry size (in bytes)

for ex:

if the time control is 40/4, that is 6 seconds per move

so time per move = 6 sec
nps = 700,000
hash table entry = 16 bytes (16 bytes is typical for many chess engines but can vary)

we have:
6 secs x 700,000 nps x 16 bytes = 67200000 bytes

67200000 bytes = 65625 kB
and
65625 kB = 64 MB

thus, hash memory should not fill up at that time control, if hash = 64 MB
i.e. this is the precise amount of memory needed (by this particular system at this particular TC)
to store all hash table info generated during a 6 sec. move

if the hash does ever become full, the performance of the engine may decrease (albeit a very small amount),
as the engine must then swap/replace hash entries instead of simply adding

and, it has been fairly reliably shown that performance can also be degraded if way too much hash is allocated...

Norm

Last edited by kranium on Wed Nov 30, 2011 4:06 pm; edited 2 times in total

descriptionPOLL:Which Hashtable is better ? EmptyRe: POLL:Which Hashtable is better ?

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Nearly all present day chess engines use hash tables. Another term for them is transposition tables. Chess programs that use hash tables create a temporary storage file as they play or analyze and store the positions they've evaluated in this file. If a position comes up later in the search (by a transposition of moves) that's the same as a position that's already been evaluated (and stored in the hash tables), they don't need to analyze it a second time -- they just pull the existing evaluation information from the hash tables and then move on to the next position.

Here's a simple example. Let's say it's White's turn to move in a particular position (the exact position doesn't matter for this example). Among White's candidate moves are Bg5 and Nc3. Black could reply to either move with a5 or Qd7. Let's say that a chess engine analyzes this position, sees the move order 1.Bg5 a5 2.Nc3 Qd7, and analyzes that position. Later in its search, it sees the move order 1.Bg5 Qd7 2.Nc3 a5 -- this results in the exact position as in the variation previously mentioned (through a transposition of moves). By referencing the existing analysis in the hash tables, the engine won't need to analyze the position again -- it'll just see that the position's already been evaluated, use that same evaluation, and advance to the next position to be analyzed. Later in its search, it hits the position after 1.Nc3 Qd7 2.Bg5 a5. Once again, this is the same position, so it uses the evaluation stored in the hash tables. And so on.

ChessBase engines allow you to configure the size of the hash tables (which are stored in your computer's RAM) in the engine selection dialogue. Hit the F3 key on your keyboard in ChessBase 8 or any of our playing programs (from Fritz6 [late 1999] onward -- this shortcut isn't present in older versions of our chessplaying programs), and you'll see the dialogue appear on your screen:


To set the hash table size, just type a value (given in megabytes of RAM ) in the box provided. The program will provide a "maximum" hash table size based on your computer's total RAM, the system resources currently being used, and any hash table size limits programmed into the engine.

It's crucial to set the hash tables to the proper value (which is frequently not the suggested "maximum"). Bigger is not always better; in fact, it can be downright harmful to an engine's performance.

Note :- This paragraph is drawn from chessbase article.

descriptionPOLL:Which Hashtable is better ? EmptyRe: POLL:Which Hashtable is better ?

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After 1080 games:same 9 ELO difference (as before) in favor for 512mb Hashtable size:
POLL:Which Hashtable is better ? 128mb_512mb

For More Details:
http://www.sedatcanbaz.com/chess/512mb128mb/

Best,
Sedat

descriptionPOLL:Which Hashtable is better ? EmptyRe: POLL:Which Hashtable is better ?

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Hmm... my Large Page Hashtable at 2048 MB fills up to 100 % while playing in come2play.com, which has 1 move/2 min rule.
Running a 3930K btw wink
So, I'm guessing I need to set the Large Page size to 4096 MB, right guys ?

descriptionPOLL:Which Hashtable is better ? EmptyRe: POLL:Which Hashtable is better ?

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