Nirvanachess 1.6 Release

What is new in this release?

• Strength Increase
• About 40 Elo stronger than Version 1.5 at long time controls (60' + 0.05')
• Evaluation Tweaks
• Added knowledge of  KR vs KP endings
• Passed Pawn evaluation is smoothed out between mid and endgame.
• Optimization
•  Slightly quicker during the mid and end games (~2%)
• Bug Fixes
• Fixed a bug with pawnstorms
• Sometimes would count pawnstorms twice
• Fixed a bug with pawn shelter
• Sometimes would count shelter pawns twice
• Fixed a bug that would cause pawns to be completely mis-evaluated.

Download Link:
http://www.mediafire.com/download/fcdz82s1g2tr9lp/Nirvanachess1.6.rar

Hyper Bullet Rating List

I have take some time off from programming Nirvana and thus now I have some free resources in order to try out an idea I was toying with previously. This rating list is not meant to be serious but is more for seeing how different engines scale with added time. The ratings are set such that Arasan 16.3 is at 2790 elo. This rating list uses a modified version GBDC12013 with only 100 opening positions. This allows for each engine to play both sides of each opening five times against each other.

i5 3210M @ 2.50 Ghz
Cutechess
32mb hash per engine where possible 
No tablebases
Ponder off
Modified GBDC122013.cgb book
6" + 0.06"
All engines 64-bit
1000 Rounds to Match up


Rank Name              Elo   +    -   games score oppo. draws  CCRL Diff
   1 Stockfishdd        3296   36   36  1000   95%  2821    8%  3181   +115
   2 Gull2.8Beta        3281   34   34  1000   95%  2821    8%  3098   +183
   3 Discocheck5.2    2974   20   20  1000   71%  2821   21%  2911    +63
   4 Smarthink1.5      2903   19   19  1000   61%  2821   23% 2831    +72
   5 cheng4.36c         2874   19   19  1000   58%  2821   25%  2810   +64
   6 Nirvanachess1.5  2821    7    7 10000   44%  2893   19% ????     N/A
   7 Arasan16.3         2790   19   19  1000   46%  2821   23% 2790    +0
   8 Rodent1.3          2721   19   19  1000   37%  2821   22% 2750    -29
   9 Rhetoric1.2        2712   19   19  1000   35%  2821   22% ????     N/A
  10 Fruit2.1             2693   19   19  1000   33%  2821   21% 2693     +0
  11 Redqueen1.1.97 2686   20   20  1000   32%  2821   20% 2670     +16


Interestingly enough all of the engines that are rated below Nirvana on the CCRL list seemed to have performed about the same at this hyper speed but the rest out performed their ratings drastically. Granted this is only against Nirvana which I suspect as being very poor at very short time controls.

PGN Download Link:
http://www.mediafire.com/view/7wx7hh67n4at54s/Hyperbullet.pgn

Nirvanachess 1.5 Release

What is new in this release?

• Strength Increase
• About 50 Elo stronger than Version 1.4 at long time controls (60' + 0.05')
• Better Time Management
• Changed how much time was allocated for repeating time controls.
• Should no longer have twice as much time as most opponents during the endgame
• Better move ordering
• So called "bad captures" are now ordered after killer moves
• A bad capture is defined by a capture that captures a less valuable piece that is defended by a pawn.
• Changed move ordering at root
• Now previous best moves are kept closer to the front of the move list
• Will no longer "throw out" a fail high at root when out of time
• Evaluation Tweaks
• Increased the speed at which doubled pawns are detected
• Slightly optimized king safety values
• Optimized pawn chain values
• Pawn chains were previously highly overvalued
• More Pruning
• Improved both futility and razoring values
• Added more pruning in Qsearch for non-discocheck moves
• More null move pruning
• The better the current position the pruning will occur
• Bad captures are now able to be futility pruned
• More aggressive aspiration search window
• Bug Fixes
• Fixed a bug with pawnstorms
• Previously the least advanced pawn on a file was considered to be the storming pawn

Download Link:
http://www.mediafire.com/download/652c6i6tl7l1lu8/Nirvanachess_1.5.rar

Nirvanachess 1.4 Release

What is new in this release?

• Strength Increase
• About 50 Elo stronger than Version 1.3 at long time controls
• Much stronger at very short time controls
• Scores 100% against version 1.3 at 2"+0.02"!
• Scores 160 elo better at 6"+ 0.05"
• Better Time Management
• Will now use its time more intelligently
• Moves that are seen as "easy" will now be played more quickly
• Will spend more time on harder moves
• Will now make effective use out of Fischer time controls
• Previously bonus time was not taken into consideration
• Better move ordering
• Moves will now be ordered more effectively in order to reduce the branching factor
• Endgame Evaluation
• Now plays King + pawns endings more effectively
• Evaluation Tweaks
• Improved King safety
• Now takes into consideration how many squares are attacked
• Now take into consideration the quality of the shelter
• Now takes into consideration "Pawn spans" a la Stockfish
• More Pruning
• Additional conditions for LMR pruning
• Bug Fixes
• Fixed a bug with move order due to initialized variables
• Fixed a bug with King safety evaluation
• Additional Features
• Now accepts the "go infinite" command
• Nirvana can now be used for in-depth analysis (if you are into that)
• Now accepts the "go depth x" command
• Now has an option for Aggressiveness
• The higher this parameter the more Nirvana will sacrifice to attack the enemy king
• Now has an option for Cowardsness
• The higher this parameter the more caution Nirvana will play
• Now has an option for Mobility
• The lower this value the less Nirvana will care about its PST and mobility

Download Link:
http://www.mediafire.com/download/p26198q95f51u47/Nirvanachess1.4.rar

Nirvanachess 1.3

What is new in this release?

• Strength Increase
•  About 50 elo stronger than Nirvanachess 1.2
• Overall Faster
• Overall 3% faster (Even without using the intel compiler!)
• Better Time Management
•  Will now use more of its time on repeating controls
• Endgame Evaluation
• Added a few more endgame specific evaluations
• Evaluation Tweaks
• Further improved passed pawn evaluations
• Added a scaling value for the bishop pair
• More Pruning
• Slight tweaked LMR and other parameters
• Bug Fixes
• Fixed a bug with move order during long searches
• Fixed a bug with certain endgame evaluations

Download Link:
http://www.mediafire.com/download/19b8dsbhk5oildc/Nirvanachess_1.3.rar

Nirvanachess 1.2


What is new in this release?

• Strength Increase
•  Over 200 elo stronger than Nirvanachess 1.1
• Overall Faster
• Minimally in the opening 1%-3%
• Significantly in the ending 20%-50%
• Hash
• Entry size reduced from 32 to 16 bytes
• Better Time Management
•  Will now use more of its time on repeating controls
• Endgame Evaluation
• Has specific evaluation procedures for certain endgames.
• No longer fails to mate in KNB vs K
• No longer suffers from blind bishops
• Evaluation Tweaks
• Better handling of passed pawns
• Small changes to pawn shelters
• Added pawn storms
• Better knowledge of good vs bad bishops
• More Pruning
• Reaches 20% deeper depth
• Bug Fixes
• Rooks on the 7th were sometimes not given bonuses
• Bishops sometimes had their mobility incorrect evaluated

Download Link:
http://www.mediafire.com/download/pvwst8n69j9ztx4/Nirvanachess_1.2.rar

Nirvanachess 1.1

What is new in this version?

-64 Bit Compile

-Now 10%-20% faster in terms of nodes per second

-Hash move is now "Free" (No move generation necessary)

-Fixed many bugs in the Evaluation function

-More Extensions, more reductions overall reaches 2-4  ply deeper under the same time controls.

-About 200 Elo stronger than version 1.0

-Various other small bug fixes

Download Link:

http://www.mediafire.com/download/8xdedm5jgm18h87/Nirvanchess_1.1.rar