GrahamW
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re:Updating Crafty - 2006/07/13 07:13
It's in with the source.
If I may quote the comments from main.c:
* 19.0 significant change to the search extension limits. first, the
*
* limit of no more than 1 ply of extensions per ply has been tossed *
* out. now, any number of extensions are allowed in the first N
*
* plies, where N=iteration_depth of the current iteration. After
*
* the first N plies, extensions are reduced by 50% for the next N
*
* plies. They are then reduced by another 50% for the next N plies *
* and then completely disabled after that. IE for a 12 ply search, *
* all extensions (even > one ply) are allowed for the first 12
*
* plies, then the extensions are reduced by 1/2 for the next 12
*
* plies, then by 1/4 for the next 12 plies, then turned off from
*
* that point forward. minor tweak (suggested by GCP) to reduce the *
* time limit by 1/4 for ponder=off games was done in time.c. fix
*
* to EvaluateWinner() to correctly realize that KR[BN] vs KRR is a
*
* draw for the KRR side if it doesn't have at least a pawn left.
*
* minor bug in RejectBookMove() would reject all moves if the op-
*
* ponent had a stonewall-type pawn set-up. it was supposed to only *
* reject castling into the attack. minor change to code in the
*
* EvaluateMaterial() function to lower the penalty for sacrificing
*
* the exchange. it was considered just as bad as trading a rook
*
* for two pawns which was wrong. change to hashing code so that we *
* can now determine that a hash entry came from the EGTB so that
*
* PVs are displayed with <EGTB> when appropriate, not <EGTB> if it
*
* originally came from the EGTB but later <HT> when it was picked
*
* up from the hash table instead. minor changes to search/searchmp *
* to make them identical in "look" where possible, for consistency
*
* in source reading if nothing else. if the first argument on the
*
* command-line is "xboard" or if the environment variable
*
* "CRAFTY_XBOARD" is set, crafty sends a "feature done=0" command
*
* to tell xboard it has not yet initialized things. significant
*
* changes to EvaluateWinner() to recognize new cases of draws such
*
* as Q+minor+nopawns vs Q+pawns as unwinnable by the Q+minor side.
*
* other cases were fixed/improved as well.
*
*
*
* 19.1 changes to the outside passed pawn and outside candidate pawn
*
* code to more correctly recognize when one side has a simple end-
*
* game position that is easy to win. futility pruning and razoring *
* (Jeremiah Penery) was added. to endable it, you will need to add *
* -DFUTILITY to the Makefile options, otherwise it is disabled by
*
* default. EvaluateWinner() had a bug dealing with KR vs KN or
*
* KRR vs KRN( that has been fixed.
*
*
* 19.2 CCT-5 version 01/20/03.
*
* changes to the LimitExtensions() macro. the extensions are now
*
* a bit more aggressive, but after 2*iteration_depth, then they
*
* taper off smoothly so that by the time the depth reaches
*
* 4*iteration_depth, the extensions are cut to zero. fixed bug in
*
* EvaluatePawns() that missed candidate passed pawns so that the
*
* new endgame stuff didn't work completely. change to hash.c to
*
* combine the two hash tables into one so that the two probed
*
* entries are adjacent in memory to be more cache friendly. A bug
*
* in moving a replaced entry from depth-preferred to always-store
*
* caused the moved entry to go to the wrong address which would
*
* make it impossible to match later. new hash table layout is more *
* cache-friendly by putting one entry from depth-preferred table
*
* with two entries from always-store, so that they often end up in
*
* the same cache-line.
*
*
*
* 19.3 change to EvaluateMaterial to realize that a rook for five pawns
*
* is also likely a "bad trade." adaptive hash table size code was
*
* added so that the hash size is set automatically based on the
*
* estimated NPS and time per move values for a specific "level"
*
* command setting. RepetitionCheck() rewritten. the old code had *
* an unexplained bug that would overlook repetitions in a parallel
*
* search in rare cases. the old cold was complex enough that it
*
* was time to rewrite it and simplify it significantly.
*
*
*
* 19.4 initial depth "seed" value changed to iteration_depth + 1/2 ply,
*
* so that fractional extensions kick in earlier rather than deeper
*
* in the search. this performs _much_ better in tactical tests
*
* such as WAC and similar suites. minor book fix for a bug that
*
* could cause a crash with book=off in xboard/winboard.
*
*
*
* 19.5 default draw score set to 1, because endgame table draws can be
*
* 0, -.01 or +.01, which translates to -1, 0 or 1 in real scores
*
* inside Crafty. +1 means a draw where white has extra material
*
* and that would break accepting draws with such a score. a few
*
* NUMA-related changes. one global variable was made thread-
*
* private to avoid cache thrashing. split blocks are now allocated *
* by each individual processor to make them local to the specific
*
* processor so that access is much faster. CopyToSMP() now tries
*
* to allocate a block for a thread based on the thread's ID so that *
* the split block will be in that thread's local memory. a few
*
* other NUMA-related changes to help scaling on NUMA machines.
*
*
*
* 19.6 new egtb.cpp module that cuts decompression indices memory by
50% *
* with no harmful side-effects. fixes to NUMA code to make SMP and *
* non-SMP windows compiles go cleanly.
*
*
*
* 19.7 changes to draw code so that Crafty will first claim a draw and
*
* then play the move, to avoid any confusion in whether the draw
*
* was made according to FIDE rules or not. minor bug in evaluate() *
* dealing with candidate passed pawns fixed. A few additions to
*
* support my AMD Opteron inline assembly for FirstOne(), LastOne()
*
* and PopCnt() procedures.
*
*
*
* 19.8 changes to lock.h to (a) eliminate NT/alpha, since Microsoft no
*
* longer supports the alpha, which makes lock.h much more readable. *
* CLONE is no longer an option either, further simplyfying the .h
*
* files.
*
*
*
Tom Veldhouse.
---------
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