Author: Tony Werten
Date: 23:51:09 04/07/04
Go up one level in this thread
On April 07, 2004 at 14:43:02, Robert Hyatt wrote: >On April 07, 2004 at 14:22:38, Vincent Diepeveen wrote: > >>On April 07, 2004 at 14:16:31, Robert Hyatt wrote: >> >>>On April 07, 2004 at 11:27:47, Vincent Diepeveen wrote: >>> >>>>On April 07, 2004 at 11:04:23, Robert Hyatt wrote: >>>> >>>>>On April 07, 2004 at 10:54:40, Tony Werten wrote: >>>>> >>>>>>On April 07, 2004 at 10:48:23, Renze Steenhuisen wrote: >>>>>> >>>>>>> >>>>>>>>>>>>I'm sure it was some implementation bug with Renze. >>>>>>> >>>>>>>Anyone, >>>>>>> >>>>>>>I only store result from the main search, so no NULL-move and no Qsearch >>>>>>>results. >>>>>>>I get a TT-hit ratio of 11.73%, of which a part will generate cut-offs. >>>>>>> (I call something a tt-hit when an entry is found with the same hashkey, >>>>>>> draft does not need to be sufficient) >>>>>> >>>>>>Hmm, I'm sorry but that's way too low. You probably have a problem with your >>>>>>hashkey. >>>>>> >>>>>>In XiniX I get a hitrate of at least 60% in normal search, >20% in qsearch. >>>>> >>>>>That can't be right unless you are talking positions like Fine 70... >>>>> >>>>>Too many have run that experiment over the years and 30% is the _highest_ number >>>>>I have ever seen reported in opening/middlegame positions. >>>> >>>>Xinix is a very efficient searching program with a good qsearch. >>>> >>>>Better qsearch means more efficient main search. >>> >>>Has absolutely _nothing_ to do with number of "transpositions" however... >> >>It actually does, because in crafty your fliprate is like 5% or so i remember >>and probably hasn't changed much sincethen. It is a result of not storing in >>qsearch and doing little in qsearch. >\ > >Here is +real+ data: > >3r4/pbr2pkp/1p1qp1p1/3n4/P1BP1PN1/1P4Q1/5RPP/3R2K1 b - - 0 1 > > time=1:00 cpu=391% mat=0 n=134503927 fh=92% nps=2.24M > ext-> chk=3336967 cap=373397 pp=44255 1rep=256105 mate=3433 > predicted=0 nodes=134503927 evals=39178023 50move=6 > endgame tablebase-> probes=0 hits=0 > hashing-> 24%(raw) 19%(depth) 80%(sat) 99%(pawn) > hashing-> 0%(exact) 14%(lower) 1%(upper) In XiniX 46% in normal search, 13% in qsearch. Altough qsearch hits are very nice (almost always a cutoff) this is one of those positions where it might not pay off. There also doesn't seem to be anything going on in this position ( or I didn't search long enough ) wich lowers the hitrates. (bm a6 ?) > >for that search, I got 24% raw hits. That is pure hash signature matches, >whether the info was useful or not. very few were exact entries (no surprise >for a program that uses PVS since most searches fail high or low), 14% were >lower bound values which means the search stopped with a fail high, 1% was an >upper bound value which means the search stopped with a fail low at this point. >The other 9% were useless because of the draft (depth remaining). The "sat" >value simply says that the table was 80% utilized during the search, that 20% of >the entries were not modified at all. The hash size was 12 million entries or >192M bytes (16 bytes per entry). > >Here is how it looks for fine #70 as an extreme example: > >8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - - 0 1 > > time=1:00 cpu=234% mat=1 n=60933197 fh=88% nps=1.01M > ext-> chk=6896348 cap=47387 pp=350507 1rep=105017 mate=2957 > predicted=0 nodes=60933197 evals=23142373 50move=0 > endgame tablebase-> probes=143144 hits=143144 > hashing-> 59%(raw) 53%(depth) 49%(sat) 99%(pawn) > hashing-> 1%(exact) 42%(lower) 4%(upper) > :))) 97% in search, 48% in qsearch. remarks: Solution found at ply 16, speed 736Kn/s ( he, it can be fast ), test stopped after 5 secs ( reached maxdepth=30 ), no EGTB Thinking about it. If Crafty would store nodes with depth<=0 it would probably get a higher hitrate in normal search as well, but loose a lot of speed. In XiniX I have lost that speed already by design choice, so it doesn't matter that much. Can you check ? Store the first ply in qsearch ( but don't probe ) and see if the hitrate goes up. Tony >There the raw hit rate was 59%. Lots of tb hits so here is the same test with >egtbs turned totally off: > > time=1:00 cpu=360% mat=1 n=137657341 fh=85% nps=2.29M > ext-> chk=17777360 cap=371216 pp=1119055 1rep=203863 mate=2094 > predicted=0 nodes=137657341 evals=52311875 50move=0 > endgame tablebase-> probes=0 hits=0 > hashing-> 53%(raw) 49%(depth) 83%(sat) 99%(pawn) > hashing-> 0%(exact) 39%(lower) 6%(upper) > > >> >>In software doing checks in qsearch and storing them the fliprate is < 1% >>usually. > >What is "fliprate"? My fh % shows the same information, namely how often I fail >high on the first move assuming I fail high at all... > > > >> >>Xinix belongs to that group. >> >>>That is simply a characteristic of the tree being searched and its size and >>>number of branches... >>> >>>If you get over 30% hash hits, something odd is going on in the middle game. IE >>>horrible move ordering or something... >> >>In contradiction a very good move ordering happens. He just researches the same >>tree time and again. >> >>In crafty you do not. You just keep searching new trees because of the instable >>qsearch+eval scores you get back. >> >>Each new iteration something <= alfa flips to >= beta, causing you a ply down to >>research for a <= alfa node possibly suddenly entire new trees you didn't search >>before. >> >>So a higher % there is a direct result from a more efficient search + storing in >>qsearch. >> >>> >>>> >>>> >>>>> >>>>>> >>>>>>Tony >>>>>> >>>>>>> >>>>>>>the tt_retrieve code retrieves a move, which I call the TT_MOVE_SUGGESTION. >>>>>>> >>>>>>>could someone provide me with a % of TT_MOVE_SUGGESTIONs in a search? >>>>>>> >>>>>>>Cheers...
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