Glass was meant to be called Chronos after Edmund has won a game of chess against Pawel with the name at stake. Unfortunately a month later it transpired that there is already an engine called Chronos CE, so we decided to change the name.

Below there is a short history of changes from version to version.

Glass 1.8
26.11.2011

- search rewritten in a non-recursive manner
- tuning of LMR and futility parameters
- eval cleanup
- bugfixes (among them important see bug, causing crashes)

Glass 1.7
20.07.2011

- bugfixes (losses on time, KBB checkmate, LMR, asymmetric values, opening book inactive in n moves per second mode)
- general code cleanup
- x64 compatibility
- simplified quiescence move generator for serious speed gain
- improved move ordering
- massive change of piece/square tables and mobility values
- some special case code for positions with low material


Glass 1.6
13.07.2010

- more parameter tuning, especially reducing agression
- history heuristic applied to late move reduction
- defining engine strength (600-2400 Elo)


Glass 1.5
29.03.2010

- many bugfixes
- pseudo-legal move generation
- late move reduction
- more aggressive, generalized futility pruning
- material imbalance evaluation
- king safety completely rewritten
- a lot of tuning

Glass 1.4
--.--.--

Two independent failed attempts by both developers

Glass 1.3
30.06.2009

- Nalimov Endgame Tablebase Support (3-6 men)
- Nullmove tuning
- No separate settings anymore for the different types of transposition tables
- Improved Time management (time control of 10s / game tested successfully)
- "analyze" command added to analyze epd files
- pawn storm code and minor eval tweaks
- opening book tweaks

Glass 1.2
03.05.2009

- multiPV support added
- changes to book file format *.gob (old books are still readable, but the new format isn't comatibile backwards)
- important bugfix in King Safety Eval
- some speed optimizations

Glass 1.1
06.04.2009

- fixed serious bug in opening book code (was deterministic)
- fixed a bug related to losses on time
- fixed a bug related to not executing simple checkmates in severe time trouble
- Enhanced Transposition Cutoff added

Glass 1.0
31.03.2009

- numerous bugfixes in search, eval, transposition table and communication
- new opening book format (*.gob)
- separate principal variation hash table to improve move ordering and to return longer lines while analyzing
- improved king safety evaluation to encourage more interesting game
- asymmetric mobility evaluation is now default
- scores 60% against older versions

Glass 0.1.0f-h
February 2009


- test versions where king safety code has been shaped

Glass 0.1.0e
January 2009

- some special case endgame code
- version that advanced to group 2 in the League of Polish Chess Programs (LPPS)

Glass 0.1.0d
28.12.2008

- eval changed to encourage rook connection while penetrating enemy camp
- program can checkmate a lone king with bishop and knight
- improved eval hashing when 50 move rule comes into play
- main transposition table used only for sorting when 50 move rule comes into play

Glass 0.1.0c
17.12.2008


- bugfix concerning illegal moves if depth 1 search is not finished (relevant only in totally crazy test positions)
- this version got a CCRL rating of 2271
- this version took place in OpenWar 5th Edition, scoring 25/65 and finishing 46th.


Glass 0.1.0b
15.12.2008


- root PVS bug fixed

Glass 0.1.0a

- a failed attempt to improve performance in bullet games


Glass 0.1.0
13.12.2008

- first semi-official release (last fix concerning choice of opening book moves, which weren't random enough)