Author: Robert Hyatt
Date: 12:01:45 04/08/04
Go up one level in this thread
On April 08, 2004 at 02:51:09, Tony Werten wrote: >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. This is one reason I had hoped you would "join" the paper on hash collisions. Your program is obviously a big departure from what I do in Crafty. It would be interesting to see how hash collision errors affects what you do... > >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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