Arasan

on Wed Feb 27, 2013 7:26 am by · on Wed Feb 27, 2013 7:26 am by

Arasan 15.2

- silent update, version number is unchanged.
- added a 64-bit version for older cpus without SSE 4.2.

http://www.arasanchess.org/arasanx-64.exe

on Thu Feb 28, 2013 6:49 am by · on Thu Feb 28, 2013 6:49 am by

Arasan 15.2 JA

Windows/Linux/Android 64/32

https://dl.dropbox.com/u/5047625/arasan-152-ja.zip

on Thu Apr 11, 2013 4:04 am by · on Thu Apr 11, 2013 4:04 am by

Arasan 15.3 is available

http://www.arasanchess.org/downld.shtml

Changes in this release:

1) Fix a bug in king cover calculation.
2) Modify root LMR logic.
3) Reduce memory usage for "makebook" utility by shrinking/packing structures.
4) Fix "makebook" so it works on Linux.
5) Improve makebook speed by optimizing Board::reset.
6) Some tweaks to trade down scoring, especially to discourage trading down from a possibly winnable to a drawish endgame.
7) Change hashtable replacement policy so exact hash code matches always replace existing entries.
8) Main search probes q-search cache for a pv move if the main hash table does not provide one.
9) Improved ordering of evasion moves.
10) Add extra time to search if resolving a fail-high at the root.
11) Thread limit raised to 64.
12) Thread split depth is dynamic based on number of threads.
13) Some code portability fixes, in particular fixing big-endian support.

about 25 ELO higher than 15.2

on Thu Apr 11, 2013 1:42 pm by · on Thu Apr 11, 2013 1:42 pm by

Code:: Games Completed = 263 of 1000 (Avg game length = 11.073 sec) Settings = RR/32MB/2000ms+100ms/M 700000cp for 7 moves, D 150 moves/EPD:E:\LittleBlitzer\openings.epd(4000) Time = 907 sec elapsed, 2542 sec remaining 1. Arasan 15.2 w32 168.5/263 159-85-19 (L: m=9 t=76 i=0 a=0) (D: r=19 i=0 f=0 s=0 a=0) (tpm=146.4 d=11.37 nps=690288) 2. Arasan 15.3 w32 94.5/263 85-159-19 (L: m=5 t=154 i=0 a=0) (D: r=19 i=0 f=0 s=0 a=0) (tpm=148.1 d=11.42 nps=663692)

It seems to be a bug...or what? think

on Wed Apr 24, 2013 5:46 am by · on Wed Apr 24, 2013 5:46 am by

Jon did not say "Thanks to bob"
smile

Arasan 15.4 released

Changes in Arasan 15.4:
1) Internal time accouting is now in millseconds, not centiseconds.
2) Fix time management to reduce losses on time in very fast games.
3) Native GUI now recognizes "offer draw" command (fixes bug in draw
detection). Also though engine now reverts to using result command
in cases of draw by rule before a move is made.
4) Remove extra quote from response to "protover" command in Winboard (so myname feature works).
5) Modify how book selectivity setting works. Selectivity has to be lower
now to select very rare moves.
6) A few more code portability fixes.
7) Fix UCI protocol bugs leading to occasional loss on time with ponder on.
8) Fix strength option scaling so play is stronger at high values.

Jon Dart wrote: None of these changes affect playing strength a lot, and whatever change there is, is mostly due to the time management fix. This version scores about +7 ELO above 15.3 in my testing.

http://www.arasanchess.org/downld.shtml

on Fri May 03, 2013 4:26 am by · on Fri May 03, 2013 4:26 am by

Arasan 15.5 released

http://www.arasanchess.org/downld.shtml

Changes in this release:
1) Fix bug that can cause illegal move from pondering.
2) Check for checkmate before returning 50-move draw.
3) Send Winboard variants in feature line (only "normal" is supported).
- The first of these fixes is for a regression introduced in 15.4.
- There should be no performance difference from previous versions, unless you are using pondering, in which case losses due to the illegal move bug may show up in 15.4.

on Tue May 21, 2013 3:30 pm by · on Tue May 21, 2013 3:30 pm by

Arasan 15.6

http://www.arasanchess.org/downld.shtml

- bug fix in search (affects multi-core searching only)
- book selectivity logic changed (50 setting is a bit more selective now)
- book.random option is fixed (was not working)
- book move kibitz for ICS is fixed so that weights are shown normalized and the book selectivity rules are applied
- fix "makebook" program to handle comments after PGN result

on Tue May 21, 2013 10:11 pm by · on Tue May 21, 2013 10:11 pm by

Not for serious games but I love this engine! wink

on Wed May 22, 2013 7:08 pm by · on Wed May 22, 2013 7:08 pm by

Arasan chess engine source is now available on github: https://github.com/jdart1/arasan-chess

on Wed Jul 24, 2013 7:14 pm by · on Wed Jul 24, 2013 7:14 pm by

Arasan 16.0 released

http://www.arasanchess.org/downld.shtml

Changes in Arasan 16.0:
1) Improvements to multi-core and multi-processor performance: limit
global memory usage, do dynamic adjustment of split depth.
2) Change book format, book weights are 0..100 not 0..10 now. New
larger opening book is included with Arasan binaries.
3) Book selectivity logic changed (again).
4) Fix bug in 50-move draw detection.
5) Move sorting no longer uses node counts; now an initial sort is
done by move score, then subsequently PV moves are moved to the front
each iteration, keeping other moves in the same order.
6) Check extensions are more limited now. Overall limit on extensions
at high ply counts from root is removed.
7) Search time can be extended more in case of fail-low or resolving a
fail-high.
8) Aspiration window changes. Fix bug that can cause array overflow in
aspiration window code.
9) Somewhat experimental self-play code added for testing (not enabled
in release builds by default).
10) Numerous adjustments to evaluation weights.
11) Score pawnless KRB vs KR and KRN vs KR as draws.
12) Bug fix: allow resignation when in fixed depth search and depth<=1.
13) Fix bug in handling of fail_high_root flag.
14) Convert to conditional variables for thread synchronizaton on Linux
+ Mac (fixes Mac OS problem where semaphores may not be cleaned up
on exit).
15) Fix stack size for threads on Mac OS (avoids bus error crash in deep
searches).

on Thu Jul 25, 2013 12:01 am by · on Thu Jul 25, 2013 12:01 am by

Looks very nice, lets wait some tests now

on Thu Jul 25, 2013 12:16 am by · on Thu Jul 25, 2013 12:16 am by

As World Rapid Computer Champion, Arasan could be included in my upcoming Supertournament Qualifier and Season 4 Championship Cycle later this year.

on Mon Sep 02, 2013 12:00 am by · on Mon Sep 02, 2013 12:00 am by

Arasan 16.1 is available from http://www.arasanchess.org.

Changes in Arasan 16.1:

1) Fix UCI protocol bug that could cause engine to hang in cases where
ponder is on and game is terminating due to a draw by repetition
or rule.
2) Some speed optimizations for pin detection.
3) Bug fix in razoring code (return razor value from search).
4) Fix time & nps display for UCI (was off by factor of 10)
5) Some pawn scoring changes.
6) Bug fix: correct some of the constants in Attacks class.
7) Fix problem in UCI multi-PV analysis mode.
8 ) Allow LMR for checking moves and recaptures if they do not
meet the extension conditions (still disable LMR if side
to move is in check).
9) Fix console input handling in Windows.
10) Add -o (output file) option to engine "test" command.
11) GUI uses .chm help file format, for compatibility with Windows Vista, 7, 8.

Mostly bug fixes, but also this version is somewhat stronger than 16.0.

In addition there are some updates/fixes in the opening book.

--Jon

on Mon Sep 02, 2013 10:49 am by · on Mon Sep 02, 2013 10:49 am by

Hopefully we see more tests on this new version

on Mon Sep 02, 2013 12:21 pm by · on Mon Sep 02, 2013 12:21 pm by

Code:: Games Completed = 1000 of 1000 (Avg game length = 14.871 sec) Settings = RR/32MB/2000ms+100ms/M 700000cp for 7 moves, D 150 moves/EPD:E:\LittleBlitzer\openings.epd(4000) Time = 4312 sec elapsed, 0 sec remaining 1. Arasan 16.0 538.0/1000 394-318-288 (L: m=290 t=28 i=0 a=0) (D: r=212 i=42 f=29 s=0 a=5) (tpm=124.2 d=10.91 nps=86119) 2. Arasan 16.1 462.0/1000 318-394-288 (L: m=241 t=153 i=0 a=0) (D: r=212 i=42 f=29 s=0 a=5) (tpm=125.1 d=10.93 nps=860570)

on Mon Sep 02, 2013 1:23 pm by · on Mon Sep 02, 2013 1:23 pm by

sad to see an older version stronger than a newer one :( , but maybe it is just for very short TC , we will see

on Fri Oct 25, 2013 6:04 am by · on Fri Oct 25, 2013 6:04 am by

Arasan 16.2 released.

on Fri Oct 25, 2013 2:53 pm by · on Fri Oct 25, 2013 2:53 pm by

+Changes in Arasan 16.2:
+ 1) Fix adjacent passed pawn code so bonus for this is independent of
+ the connected passer bonus. Adjust various passed pawn related
+ scoring params.
+ 2) Add engine console command for perft.
+ 3) Adjust scores for Rook on 7th and make dependent on game phase.
+ 4) Fixes to weak pawn scoring and outpost code.
+ 5) Simplify and fix SEE function. Use variant version with quick exit
+ when only need to know if score is above or below a threshold.
+ 6) Improvements to move ordering for check evasions.
+ 7) Fix bad bug in lazy eval code of scoring module.
+ 8) Bug fix: don't set the retrieved hash entry type to Invalid in
+ cases where the score is in bounds but moves have been pruned.
+ 9) Bug fix: remove redundant increment of parentNode->num_try in searchSMP.
+ 10) Further clean up & optimize pinned piece detection.
+ 11) Static null margins & futility margins adjusted.
+ 12) Fix KBPK draw detection.
+ 13) Makefile support added for a popcnt-enabled 64-bit Windows build.

<https://github.com/jdart1/arasan-chess/commit/515d4a8b05863bc92f6af8d4773f30e5c38bbe18>

on Sat Oct 26, 2013 12:07 am by · on Sat Oct 26, 2013 12:07 am by

I know it is weak compared to stockfish but i like its speed... lol

on Sat Nov 02, 2013 5:07 am by · on Sat Nov 02, 2013 5:07 am by

Arasan 16.2

- silent update, version number unchanged
- Windows installer file changed (it now installs correct version of engine)

http://www.arasanchess.org/downld.shtml

on Sat Nov 02, 2013 6:43 am by · on Sat Nov 02, 2013 6:43 am by

Updated versions should be renamed because unless you do Fritz will not let you stick it in it will say the engine already exists so for me it is pointless to download it because I will not be able to install it Just have to wait on 16.3. Thanks

on Fri Dec 06, 2013 7:19 am by · on Fri Dec 06, 2013 7:19 am by

Arasan 16.3
http://www.arasanchess.org/downld.shtml

on Thu Mar 27, 2014 8:08 pm by · on Thu Mar 27, 2014 8:08 pm by

Jon Dart wrote:Arasan 17.0 is available from http://www.arasanchess.org.

Changes in Arasan 17.0:
1) A common hashtable is now used in both quiescence and non-
quiescence search, instead of using a separate q-search eval
cache (hashtable stores static evals so also serves as an
eval cache).
2) Scoring module no longer does lazy eval.
3) Opening book format has changed. Manual tuned book file is
now annotated PGN instead of a custom text format. Book code
is simplified.
4) Opening book is no longer modified at runtime by result and
score learning. Only position learning (aka permanent brain)
is supported now.
5) Improvements to opening book and ECO classifier.
6) Qsearch no longer does pre-selection of capture targets.
Qsearch forward pruning margin and logic changed.
7) Bug Fix: correct time field of "post" output for Winboard/xboard
(was off by factor of 10).
8) Bug fix: declare on startup for UCI that the tablebase type
option is "Tablebase type", not "TablebaseType".
9) Bug fix: check for previous move legal before returning draw
score.
10) Bug fix: Don't apply history pruning to moves before the
history phase of move generation.
11) Bug fix to KP + wrong Bishop vs. K draw detection.
12) Bug fixes to lockless hashing. But also: restore validity
check for moves fetched from hash, since lockless hashing
is not 100% reliable.
13) A few evaluation changes.
14) Improved debug output when -DSEARCH_STATS enabled.
15) Performance fix: remove unneeded update of node count at end
of search function.
16) Change to time usage: generally uses more time in early phase
of games.
17) Changes to razoring.

Overall this version is measurably stronger than 16.3 in my testing but it is not a huge difference. However, there are significant internal changes and I expect it will play differently from 16.3. The opening book is also significantly re-done in this version.

on Wed May 07, 2014 4:58 am by · on Wed May 07, 2014 4:58 am by

Arasan 17.1
http://www.arasanchess.org/

Changes in Arasan 17.1:
1) Scoring changes: connected passer code, knight and bishop
piece square tables, new king safety scoring.
2) Add special-case eval code for K vs K+R and K vs K+Q endgames.
3) Bug fix: validate hash move in q-search before using it.
4) Changes to handling of book selectivity option.
5) Adjust variable strength option so bottom end of strength scale
is lower (will blunder sometimes).
6) Increase ply depth in reduced strength mode for very low material
endgames (engine was having difficulty mating in these cases
even at moderate strength settings). This also fixes some
problems with playing into stalemate.
7) Better handling of out-of-memory errors when allocating hashtable.
8) GUI fix: initialize all engine options at start of game. Fixes
problem with resignation setting not being obeyed.
9) GUI fix: clear any previous game result and other details after
loading a position file.

This version also has significant changes to the opening book. Overall it is measurably stronger than 17.0 but it is not a huge difference.

--Jon

on Fri May 30, 2014 4:53 am by · on Fri May 30, 2014 4:53 am by

Arasan 17.2
http://www.arasanchess.org.

Changes in Arasan 17.2:

1) Fix "st" command in Winboard protocol to interpret time as seconds.
2) Scoring changes: king safety, king cover, weak pawns.

The king safety changes are significant (there was a bug in the 17.1 scoring code). Also this version has quite a few changes to the opening book.

--Jon

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