GIBBON Home Page
Links - Siamang ? - More about Gibbons
- How Gibbon works - Contact
Welcome to Gibbon Home Page.
Notice : uci chess modules need a Graphical Interface
(as for instance, Arena) to display moves.
Notice : if download fails, try this other page.
|
Version |
Estimated strength |
Release Date |
|
2260 |
2009-03-01 |
|
|
2240 |
2009-02-10 |
|
|
2160 |
2007-09-27 |
|
|
2120 |
2007-04-14 |
|
|
2100 |
2007-03-14 |
|
|
2090 |
2007-01-15 |
|
|
1950 |
2006 |
|
|
1850 |
2005 |
|
|
1850 |
2004 |
|
|
1700 |
Massy 2003 |
|
|
SmallC-82 - uci |
1600 |
Massy 2002 |
|
SmallC-earlier
versions => to be provided |
1200 |
|
Gibbon originates from a old fixed depth C-programm called Small-C.
Small-C was born around 1990 and would compute 200 nodes per seconds at
that time. Around year 2000, it came to take part to the French Championship in
Massy where the programm clearly established itself as one of the most heavily
bugged ... Fortunately, it has been much improved since then, and evolved into
Gibbon.
Gibbon implements the UCI protocol.
Still, you can run it in console mode (type gibbon.exe -console or
double-clik gibbon and then type console <enter>).
Features :
- PVS
(Principal Variation Search) algorithm with iterative deepening and aspiration
- Nullmove
(R=3)
- Move
ordering with Static Exchange Evaluation applied to captures
- Transposition-table
move and Killermoves
- Non-PV
nodes pruning (late move pruning based on history rank
and fail-low/fail high history)
- Static
Exchange Evaluation
- Futility
pruning - Extended futility pruning
- Not
activated or not used :
Extended
Transposition Cutoff, Fractional extensions
- Internal
Iterative Deepening
- Pawn-attack,
evasion heuristics
- Extensions
(checks, passed pawns, pawn-attacks, recapture, pawn-endings)
- Two
parts hash-tables, pawn hash-table
- Quiescence
with 1 check allowed on first quiescence move
- Single
move check extensions in quiescence
- Incremental
move generation (no bitboards)
- Opening
book (Small.txt)
- Pawn
structure hash table
- Simple
evaluation when sufficient material imbalance ("Lazy Eval")
Particular features :
- It
is possible to add manually pgn games to the opening book, or to retrieve
games.Gibbon just adds statistics between () after each move to keep a
record
of the results.
- HRNFLPS-FOG-HWLANR
release
-
Horribly-Really-Not-Fruit-Like Programming Style
- Full-Of-Gotos
-
Hard-Work-Late-At-Night-Release :-)
=> besides, this is one good reason
why I do NOT feel compelled to publish the code
- Incremental move generation (no bitboards)
=> Gibbon knows all playables
moves, material, mobility, and check-squares
- Sometimes/someday assymetric search and evaluation
- Evaluation function
with
- castling
- mobility
- development
- position
- pawn structure, depending
on king positions
including passed pawns
and opposite side castling
- king safety
- two bishops
- opposite colour bishops
- dedicated rules for
win/loss/draw detection in particular positions
K+P versus K
K+Pawns versus K+Pawns
K+R+1P versus K+R
K+Q versus K+Q
K+bad_B+rook_P versus K
K+N versus K+P
K+B versus K+P
K+R versus K+P
=> it is somewhat risky as it sometimes
implies some kind of a bet,
but seems to be paying
off as these positions very often
degenerate into clear
cut results
- simplification bonus for
winning side
- counterplay prevention for
winning side
- incentive to keep queen in
case of material deficit
- incentive to keep at least
one pawn
- incentive to avoid
transitions to losts endgames with lonely night
- no incentive for minor
pieces on key squares
- incentive for king to go
with passed pawns
- incentive for out-of-reach
passed pawns
- king centralization
- draw cases
Acknowledgements
- to all contributors of the
chess community on the net
Visitors :