Deuterium
by Ferdinand Mosca

Deuterium is a winboard engine that is based on TSCP or Tom's Simple Chess Program by Tom Kerrigan.

https://sites.google.com/site/deuteriumengine/home

Deuterium v12.01.30.1070

1. Time control bug fixes
2. Modify search prunning and reductions
3. Modify search extensions
4. Some parts in move generation and evaluations are now using bitboard
5. Modify move ordering
6. Use staged move generation for winning capture and hash moves
7. Added support for polyglot book
8. Modify deuterium.ini file

https://sites.google.com/site/deuteriumengine/downloads-1/deuterium%20v12.01.30.1070.rar


deuterium v12.01 polyglot book
https://sites.google.com/site/deuteriumengine/downloads-1/deuterium%20v12.01%20polyglot%20book.rar

Deuterium 13.1.31.113
https://sites.google.com/site/deuteriumengine/files/deuterium

Version 13.1.31.113 (11August13)

* 40 to 60 elo increase from previous version.

1. Evaluation
  a. Fixed passed pawn code
  b. Fixed connected passer code
  c. Fixed backward pawn code and penalties
  d. Modify knight outpost and pcsq table values
  e. Added queen safe contact check bonus
  f. Added hanging piece penalty
  g. Added weak pawn penalty
  h. Tune king safety scores
  i. Added draw evaluation for kbp-k, where pawn is a rook-pawn
  with a wrong bishop color.
  j. Added draw evaluation for kp-kq where pawn is at 7th rank
  on rook-pawn or bishop-pawn
  k. Added knowledge to win kbn-k ending
  l. Tune some eval parameters with CLOP and cutechess-cli
2. Search
  a. Improve main search prunning
  b. Improve LMR conditions
  c. Modify qsearch prunning and level of searching check moves
  d. Tune reduction and prunning margins and conditions using
  CLOP and cutechess-cli
3. Others
  a. Added Multi PV mode
  b. Added play mode, SPAR and RATED. In SPAR mode
  the engine will try to match opponent's strength when
  engine has already gained around 3 pawns. RATED
  mode is the default set at maximum strength.
  c. Done couple of optimizations on some parts of the code.
  d. Modify deuterium.ini file
  e. Auto detect hardware capable of using POPCNT

Deuterium 14.1.32.119
- 60-80 rating points increase
https://sites.google.com/site/deuteriumengine/files/deuterium

Deuterium v14.2.33.276

Code:

Version 14.2.33.276 (21June2014)
1. Evaluation
   a. Remove redundant piece evaluation
   b. Re-write pawn storm and pawn king shelter code, this includes hashing for speed
   c. Tune pieces mobilities
   d. Tune material value and piece square tables via deuterium eval auto-tuner
   e. Improve material imbalance scores
   f. Improve pawn passer penalties, these are passers that are blocked by own and opp pieces
   g. Added bonus score for knights that block enemy isolated pawn
   h. Tune bishop pin evaluation
   i. Added candidate passer
   j. Added hidden passer
   k. Fixed a two-bishop bonus, there should be at least 1 light and 1 dark bishop
   l. Fixed rook behind own pawn
   m. Tune combination attacks to opp king
   n. More accurate determination of knight outpost feature
    
2. Search
   a. Added qsearch delta pruning
   b. Modify main search futility prunning, equal captures are now not pruned and reduced
   c. Do not prune and reduce when the move checks opponent's king in main search
   d. Added iteration pruning in main search
   e. Do not generate minor promotions except in root nodes
   f. Tune late move reductions
   g. Do not extend check moves in non-pv nodes
   h. Modify time management for TC without increment and move control periods
   i. Improve pondering
   j. Fixed pawn push to 7th rank extension
   k. Allow killer moves to be pruned
   l. Added counter move heuristics
   m. In move ordering non-capture moves that allows to be captured are penalized

3. Others
   a. Disable support of xboard/winboard protocol
   b. Implemented uci protocol
   c. Some uci options implemented
      * Hash
      * Ponder
      * OwnBook
      * MultiPV
      * UCI_ShowCurrLine
      * UCI_ShowRefutations
      * UCI_LimitStrength
      * UCI_Elo
      * UCI_AnalyseMode
      * UCI_Opponent
      * UCI_EngineAbout
   d. Additional engine options
      * EvalHash
      * Pawnhash
      * Resign
      * Log
      * DeuteriumRating - for auto calculation of contempt, together with UCI_Opponent info
      * Scorpio Egbb options, such as use, cache size, path, load type, and others
      * BookFile
      * MidGameMobilitypecent
      * EndGameMobilitypecent
      * LateMoveReduction
      * FutilityPruning
      * NullMove
      * EndingExtension, PawnTo7thRankExtension, and RecaptureExtension
   e. Commands from gui supported
      * uci, isready, setoption, ucinewgame, position, fen, startpos
      * go, searchmoves, ponder, depth, movetime, wtime, btime, winc, binc, movestogo, mate, infinite
      * stop, ponderhit, quit
   f. Info supported for gui
      * depth, seldepth, time, nodes, pv, multipv, hashfull
      * score, cp, mate, lowerbound, upperbound
      * currmove, currmovenumber
      * nps, tbhits, string
      * refutation, currline, option
   g. New egbb probe code to support for up to 6-men scorpio egbb. This is not fully tested, I will update the engine
      once I get the full set of 6-men egbb.
   h. Done some minor optimizations, and bug fixes
   i. When Uci_LimitStregth is set, the engine will also play inferior moves from the book. As the
      Uci_Elo is increased the weight or quality of moves selected also gets higher. In actual play the engine will not move
      quickly when moves are from the book to avoid the user getting intimidated. Another feature is when the engine has a remaining time
      below 1 minute the time pressure feature is activated and the engine will make (90% probability) more inferior moves.
      Under Arena gui you can set engine elo by going to Levels -> Limit Playing Strength to Elo. Under winboard gui, install the engine
           as uci, then Engine -> Engine #1 Settings then check the Uci_LimitStrength and adjust elo in Uci_Elo, minimum elo = 1000
           and maximum elo = 2800. The weakening algo is based from multipv, and blunder threshold depending on how far the uci elo value
      is set from 2800. As the uci elo is decreased the multipv is increased and the most inferior move will be played.
   j. When using scorpio egbb, the newly generated egbb should be used. Download link from here. http://shawul.olympuschess.com/egbb/
      Deuterium 64bit will use egbbdll64.dll file while for 32bit, it will use egbbdll.dll. Better is put these two files where egbb files
      are located. It should be EgbbProbe 4.1.

https://sites.google.com/site/deuteriumengine/files/deuterium

Deuterium 14.3.34.130
https://sites.google.com/site/deuteriumengine/files/deuterium

An Android compile is also included in above package. Tested working under Chess for Android. According to posts in other forums, it should work with Android Lollipop too. Another engine for Androiders is good news. To be rated soon. Follow my blog.

Deuterium 2018.1.35.514

https://sites.google.com/site/deuteriumengine/files/deuterium

Deuterium v2019.1.36.50

https://sites.google.com/view/deuterium-chess/download/engines/chess