I measure the percentage of transposition table lookups (probes) that get a hit - a hit meaning there is info about the requested position already stored in the table. And I'm getting around 17-20% hits on average.
When I run other engines in Arena they show 99%-100% in the Hash column. So I'm wondering if that percentage is hit rate as described above, and if so how does one get hit rate so high? I mean, positions don't repeat that often within the search tree do they?
Transposition table utilizattion
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Re: Transposition table utilizattion
The value displayed in Arena is hash full, not hit rate. I usually get 25-30% hash hits midgame if I give sufficient space for the table.
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Re: Transposition table utilizattion
Ah, hash full makes much more sense with those percentages. Thanks for the clarification.
Anyone know what kind of hit rate most top engines get these days? With say 1GB table size?
Anyone know what kind of hit rate most top engines get these days? With say 1GB table size?
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Re: Transposition table utilizattion
Depends on the position. Normal middle game maybe 20-30% max. In endgames like fine #70, >75%...zd3nik wrote:Ah, hash full makes much more sense with those percentages. Thanks for the clarification.
Anyone know what kind of hit rate most top engines get these days? With say 1GB table size?
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Re: Transposition table utilizattion
I did a test on Andscacs with current developing version.
Go depth 25 from start position
Go depth 25 from start position
Code: Select all
hash nodes stored not found found % found over found+not found
128 MB 53.425.849 65.716.083 36.862.078 18.983.223 34%
256 MB 64.437.112 78.582.936 43.534.378 23.853.827 35%
1024 MB 118.011.879 143.221.524 77.990.897 45.678.716 37%
4096 MB 74.634.324 88.762.678 48.235.382 29.907.519 38%
Daniel José - http://www.andscacs.com
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Re: Transposition table utilizattion
Thanks for the feedback guys. It's good to have a sanity check every once in a while.
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Re: Transposition table utilizattion
what is "found"? Signature match? Signature match + draft sufficient to use? Signature match + draft sufficient + bound good enough to stop search???cdani wrote:I did a test on Andscacs with current developing version.
Go depth 25 from start position
Code: Select all
hash nodes stored not found found % found over found+not found 128 MB 53.425.849 65.716.083 36.862.078 18.983.223 34% 256 MB 64.437.112 78.582.936 43.534.378 23.853.827 35% 1024 MB 118.011.879 143.221.524 77.990.897 45.678.716 37% 4096 MB 74.634.324 88.762.678 48.235.382 29.907.519 38%
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Re: Transposition table utilizattion
"Found" is just signature match.bob wrote:what is "found"? Signature match? Signature match + draft sufficient to use? Signature match + draft sufficient + bound good enough to stop search???cdani wrote:I did a test on Andscacs with current developing version.
Go depth 25 from start position
Code: Select all
hash nodes stored not found found % found over found+not found 128 MB 53.425.849 65.716.083 36.862.078 18.983.223 34% 256 MB 64.437.112 78.582.936 43.534.378 23.853.827 35% 1024 MB 118.011.879 143.221.524 77.990.897 45.678.716 37% 4096 MB 74.634.324 88.762.678 48.235.382 29.907.519 38%
Daniel José - http://www.andscacs.com
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Re: Transposition table utilizattion
And what is the reason for the small difference between "nodes" and "found + not found"?cdani wrote:"Found" is just signature match.bob wrote:what is "found"? Signature match? Signature match + draft sufficient to use? Signature match + draft sufficient + bound good enough to stop search???cdani wrote:I did a test on Andscacs with current developing version.
Go depth 25 from start position
Code: Select all
hash nodes stored not found found % found over found+not found 128 MB 53.425.849 65.716.083 36.862.078 18.983.223 34% 256 MB 64.437.112 78.582.936 43.534.378 23.853.827 35% 1024 MB 118.011.879 143.221.524 77.990.897 45.678.716 37% 4096 MB 74.634.324 88.762.678 48.235.382 29.907.519 38%
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Re: Transposition table utilizattion
Sorry, I didn't explain. Nodes are the reported nodes at the end of the search, so they are not directly related to Hash table.Sven Schüle wrote: And what is the reason for the small difference between "nodes" and "found + not found"?
Daniel José - http://www.andscacs.com