/***************************************************************************/
/* micro-Max version 4.8 (~1950 characters) features: */
/* - recursive negamax search */
/* - all-capture quiescence search with MVV/LVA priority */
/* - (internal) iterative deepening */
/* - best-move-first 'sorting' */
/* - a hash table storing score and best move */
/* - futility pruning */
/* - king safety through magnetic frozen king */
/* - null-move pruning */
/* - Late-move reductions */
/* - full FIDE rules (expt minor promotion) and move-legality checking */
/* - keep hash + rep-draw detect */
/* - end-game Pawn-push bonus, new piece values, gradual promotion */
/***************************************************************************/
/* The Fairy-Max version reads the piece description from a file fmax.ini */
/* The format supports many fairy pieces, including hoppers. */
/* f) now supports 15 piece types, by requisitioning WHITE bit */
/* g) supports larger board width. */
/* h) castling bug ('in-check by non-captures') corrected */
/* i) rep-draw bug ('side-to-move') corrected */
/* k) allow user underpromotions, recognize & ignore 'variant' command */
/* l) edit bug corrected (i & j file clear) */
/* m) piece values no longer quantized, game-stage counting bug corrected */
/* n) edit-menu K-side castling bug corrected. */
/* o) retrieve the requested variant from the .ini file */
/* p) clear hash table on variant switch */
/* q) reduced piece-material count for better Pawn push */
/* r) hash-table bug corrected (X still ORed with flags) */
/* s) Bug that prevented initialization center points corrected */
/* t) castling bug after edit fixed */
/* u) converted to protocol 2; ping implemented */
/* v) white e.p. rights hash bug fixed; */
/* w) piece indicators programable, multi-path support */
/* x) e.p. changed to support Berolina Pawns */
/* y) capture value of 6-7th-rank Pawn reduced in Shatranj */
/* z) bug in promotion input corrected */
/* A) stalemate-detection bug in printResult fixed */
/* B) Invalidate hash on game-level promotion (might be under-promotion!) */
/* C) King move evaluation based on negative piece value in stead of nr */
/* D) WB memory command added, undo fixed */
/* E) 15th piece read in */
/* F) accepts ini fileargument */
/* G) bug in calculation ASCII promotion character fixed */
/* H) unified normal and shatranj source */
/* J) rewrite under-promotion code, fixes persistent bug there */
/* K) o[] and oo[] made int to make fairymax work on big-endian machines */
/* L) added Resign option feature (using new WB protocol) */
/* M) char -> signed char for better portability */
/* N) add PV printing and multi-PV support */
/* O) non-Rook castling, 6th-rank promotion, independent B/W piece naming */
/***************************************************************************/
4/6/2009 Unified source of ShaMax and Fairy-Max into single fmax.c file, and
created this ChangeLog from the until then self-documenting source.
6/2/2009 Promotion code rewitten to not refer to default piece characters.
9/3/2009 Fixed big-endian bug in reading inifile (char with int format),
and added some option features to make Fairy-Max useful as test
engine for GUIs that want to implement the WB protocol extensions.
9/16/2009 Made signedness of char in AI explicit
27/12/2009 Added PV updating through the triangular-array method. Also added
a multi-PV option to print lines within a certain sccore margin.
15/1/2010 Improved Makefile, updated docs
Implement independent naming of white and black pieces. (So mirror-
image pieces can use same letter.)
Change castling code to allow castling with any corner piece type.
Implement 6th-rank promotion based on 'Queen' value.
Makruk added as new variant to the fmax.ini file.
16/1/2010 Fixed bug in Shatranj result claims.
Flip eval sign when side-to-move changes through WB color command.
17/1/2010 Removed Shatranj stalemate claim again, as it was never triggered.
1/11/2010 Implement counting of pieces, and extinction win condition.
Add engine option to allow subdivision of variant fairy.
Add FIDE vs Nutty Knights as variant fairy/FIDE-Nutters
Allow white and black to promote to a different piece type.
2/11/2010 Implement duple-check rule.
Add Spartan Chess as variant to fmax.ini.
Update docs.
1/12/2010 Version 4.8Q, implementing a reverse setup command for sending
pieceToCharTable and initial position to the GUI, sub-specification
of variant fairy through an engine-defined option, allowing Seirawan-
type gating moves in search. Seirawan Chess is added as new variant,
plus several new combinations of Chess with different armies
7/10/2011 Version 4.8R, keeping better track of which pieces are virgin in a
setup position, and have a better distinction between use of the '4'
move-rights code between an initial double-step jump without e.p.
rights (as could so far only be used for Pawns, as the Spartan
Hoplite), and castlings. As a result even royal pieces can now get
an initial double-step other than castling, which has been used to
implement Cambodian Chess as a sub-variant of Makruk (selected
through a new option). Falcon Chess was added as a new variant.
12/2/2013 Version 4.8S. Fixes a lot of bugs:
* Setting up Seirawan positions with ungated pieces
* Making Seirawan gating with already gated pieces illegal
* Fix undo in Seirawan (by remembering gatings)
* Recognizing drop moves as illegal moves
* Hash-table was only half used
* Spurious result claims after under-promotion
* False mate claims in Spartan when promotion to K was possible
* Fix bug in Berolina e.p. capture that is actually non-capture
* Fix conditions for check extension on capture of checker
* Fix Clear Hash option, which did not work at all
* Fix addition of 6th & 7th-rank Pawn bonus when setting up position
* Adapt score by true piece value in case of (under-)promotion
In addition it prints msec-accurate timing info,
and can implement limited range sliders of range up to 5.
Some game definitions using the Remarkable Rookies army (which
uses a range-4 Rook) have been added as sub-variants of fairy.
8/9/2014 Version 4.8T. Three bug fixes, some enhancements, two new variants:
* mark Rook non-virgin after castling, so it cannot gate in Seirawan
* Fix printing of variants feature in MaxQi
* Sending the setup command now also works with 3rd-rank Pawns
* Allow sending a parent variant with 'setup'
* Implement new method for indicating promo-zone width = 3
* Implement new variant nocastle
* Implement new variant ASEAN Chess
* Add option to play Makruk with Ai-Wok in stead of Met
17/10/2014 Version 4.8U. Four new variants were added:
* Charge of the Light Brigade
* King of the Hill
* Bifurcator Chess
* Team-Mate Chess
General game-playing enhancements:
* Hoppers can now be specified as hopping over friendly pieces
only, and the point where the second move leg starts can be
moved to the step just before hitting the platform.
* Sliders will now toggle to their secondary move only once,
allowing bent riders at the expense of crooked ones.
* Code is added to recognize the situation 'bare King', and
give higher award for cornering it in that case, to make mating
with many weak pieces (as regularly occurs in Makruk) easier.
* When a mate of the bare King in one corner cannot be found,
points will be awarded to drive the King out of that corner to
another one, allowing it to successfully perform KBNK-like mates.
* Make it possible to mark pieces as invalid promotion choice
Embracement of new standards:
* Add logo, and install it according to new 'plugin standard'
* Install a (new) .eng file to comply with the plugin standard
* Issue the (new) XBoard 'piece' command for all non-standard pieces
New options:
* Fifty-move claiming can be adapted to the need of the variant
* A comment line can now be displayed with each variant through
an 'Info' button in the engine options
Bugfixes, two of fatal bugs:
* Fix printing of Seirawan gating moves
* Correct the moves of the Marshal in the Rookies army of CWDA
* suppress emission of a spurious (garbled) setup command at startup
* Fix positioning of Pawns in ASEAN Chess in setup command
22/10/2014 Version 4.8V. Bugfix release for 4.8U:
* Fixes null move, which was broken by the bare King patch, as that
always set material (R) to 4, not just when bare King was detected.
26/1/2016 Version 5.0a
A rather drastic enhancement of the general capabilities:
* Analyze mode is supported, meaning arrival of input is tested
during search. Both Linux and Windows code was added for this
* Move exclusion during analysis is supported (feature exclude=1)
* The number of board ranks is no longer fixed at 8, but can have
any value up to 16. This required the promotion 'upgrade' to come
from a table pt[], rather than being derived from rank number
through a hard-coded expression
* The promotion code now uses the true value of promotion pieces in
the search, rather than assuming Q and correcting it at game level
* Pawns can start on other ranks than the 2nd, and would normally
start at the edge of the promotion zone as indicated by the =N
suffix to the board size in the ini file
* A negative N in the =N suffix now does affect on which rank the
Pawns are placed, but leaved the promotion zone depth at 1 rank
* A spin-off of the table-driven promotion is that the promotion
piece can be made file-dependent. This is currently used to set
the choice to the piece that starts on that square, as a side
effect of starting the Pawns on 4th rank
* Initial triple pushes of Pawns can be e.p. captured on both
skipped squares on 10-rank boards, when they are specified as
first move on the white Pawn
* It is possible to define on Pawns a move that is both an
initial triple push as well as a double push when advanced only
one square. This uses the code that normally would be a 5-push
* Any pair of royals will now be subject to the procedure of
bare-King detection, and increase of its centralization weight,
rather than just piece 3 and 4. This makes it easier to order
the Kings last, for better LVA move sorting
* Stalemate can be configured as a win, currently triggered by
defining value -2 for the 9th piece (which then is a royal)
* The castling-through-check test now can test more than the
3 squares starting at the King from-square, and really tests
upto the square next to the King destination. This would work
for castlings of any King stride >= 2
* The castling emptiness test now works for strides up to 4,
on boards of any width (was 3, and flaky for K-side 10-wide)
* Repetition detection now also is done inside the tree,
making it possible to plan for sacrificial perpetuals
* Bare-King checkmating is improved, by clearing the hash
table after every move (except mate scores and game history).
* The case with color-bound pieces is now handled by changing
the centralization table as soon as the bare King visits
a corner square into one that penalizes only the adjacent
two corners
* Against bare King all reductions are switched off, and a new
2-ply extension is granted on a bare King leaving a corner.
This speeds up finding corner mates.
* A variant-specific file is used to pre-charge the hash table
with positions that are protected from overwrite. A file for
Makruk to help recognizing some difficult mates is included
in the install
* New engine-defined options 'Save in hash file' (button) and
'Automatic persistent-hash dialog' (checkbox) can be used to
add positions to this persistent hash file.
* moves with bent trajectories can now be defined in the ini
file by adding the desired secondary step as third parameter
* clear hash on null-move switch, rather than spoiling the key
These enhancements have made it possible to add many new
variants, all out of reach before:
* Los-Alamos Chess (6x6 without Bishops)
* Janus Chess (10x8 with two Archbishops, stride-4 castling)
* Roman Chess (10x10, with two Commoners)
* Mexican Chess (10x10 with 2 Camels and Pawn triple-push)
* Ciccolini's Chess (10x10 with Adjutants (BDD) and Zebras)
* Grande Acedrex (12x12, game from 1283AD with bent sliders)
* almost-Wildebeest (11x10, with Gnu and 2 Camels)
17/2/2016 Version 5.0b
Mostly bug-fixes, and some small interface improvements:
* Input of Makruk promotion moves (broken by 5.0a) fixed
* Fix false game repetitions from undo messing up game history
* Fix dropping out of analysis mode in checkmate position
* Improve game-phase definition to prevent King chasing
* Grand Acedrex piece values set to encourage Zebra promotion
* Randomization obeys 'random' command, suppressed in analysis
* Print mate scores according to new CECP standard
* pieceToChar strings adapted to new XBoard piece order
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