1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
|
Phalanx is a chess playing program
Copyright (c) 1997, 1998 Dusan Dobes
LICENSE AND WARRANTY
- Phalanx is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
- Phalanx is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
along with Phalanx; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA.
WHERE TO GET PHALANX
ftp://sunsite.unc.edu/pub/Linux/games/strategy/ (and mirrors)
ftp://ftp.math.muni.cz/pub/math/people/Dobes/
COMPILING, PORTABILITY
Compiling is simple, at least under Linux. Just type `make'. Phalanx is
developed under GNU C, GNU Debugger, and GNU Make. It's probably possible to
compile it on many different platforms, but today i have no oportunity to try
it on any other platform than Linux and HP-UX. If your system does not
support GNU exensions (e.g. long options), remove '-DGNUFUN' from DEFINES in
makefile. If you have incompatible 'make', try this:
$ cat *.c > allphalanx.c; cc -O allphalanx.c -o phalanx
INTERFACE, COMMAND LINE OPTIONS
Phalanx is xboard compatible. Running with xboard: 'xboard -fcp phalanx'.
Note that permanent brain (pondering) is off by default. Newer versions of
xboard set it on with the 'hard' command. If this does not work, try
'xboard -fcp "phalanx -p+"' or (for <4.0.0 versions of xboard) change your
initString (see Xboard documentation for details). It's better to stop
permanent brain in both programs, when playing Phalanx against another
program on a machine with one CPU.
It's also possible to run phalanx without xboard. Do "phalanx -h" to get
a list of command line options. One important command of phalanx's ASCII
interface is "help".
MORE ABOUT INTERFACE
I'm trying to write an interface that fits following three requirements:
- Xboard compatibility. For best results, get the latest version of Xboard.
- shell-like interface that allows running commands in a batch. It's very
useful for testing. Example: look into the file test.fin. It's a set
of chess problems and solutions. You can simply send this file to
Phalanx's stdin:
$ phalanx -c+ -o- -b- -f10 < test.fin | tee result
( Where: -c+ .... use cpu time
-o- .... don't use polling input
-b- .... no opening book
-f10 ... fixed time 10 seconds per move )
Watch how it works.
- Acceptable ASCII interface.
OPENING BOOK
From version VI, there are two book files - primary (pbook.phalanx), and
secondary (sbook.phalanx). You can specify book directories via command line
(-P, -S) or use environment variables PHALANXPBOOKDIR and PHALANXSBOOKDIR.
Otherwise Phalanx tries to find its book files in current directory
(./book.phalanx, ./sbook.phalanx) and finally in compiled-in directory
(/usr/local/lib/phalanx). You can change the compiled-in directory in
makefile.
- pbook.phalanx is 'hand'-written, text book. One line per position, sorted.
This time, it's bigger than really needed, because it was the only book
file till version V. The size will be smaller and the line format might
change to EPD+SAN in future.
- sbook.phalanx is binary book, generated from large PGN files. Six bytes
per move (4 hash key, 2 move). You can generate your own sbook.phalanx
with 'phalanx bcreate', like this:
$ ./phalanx bcreate < manyGMgames.pgn
or:
$ ./phalanx bcreate 1250000 < manyGMgames.pgn
( where 1250000 is internal buffer size in cells. One cell takes 12 bytes.
Bigger is better, only if it's too big a part of the buffer is unused.
E.g. 1250000 is enough to parse Crafty's 'medium' book source - 29MB. )
A position is first searched in pbook.phalanx. Only if it's not found there,
sbook.phalanx is searched.
INSIDE THE MACHINE
Phalanx uses (traditional) 10x12 board implementation. There are three
often used board implementations: "8x8" (GNU Chess), "bitboard" (Crafty),
and "10x12" (Nimzo, Phalanx). In short, "10x12" is easy to implement and
the code and basic data structures are small ( == fast on PC). The engine
uses many well known techniques: PVS (principal variation search),
transposition/killer table, static-eval cache, history killers, SEE (static
exchange evaluator), null move pruning, forward pruning, internal iterative
deepening, chess-specific extensions.
AUTHOR
Dusan Dobes, dobes@math.muni.cz
HISTORY
The rest of this file is history of Phalanx.
I First version to play a legitimate game, it finally knows all rules.
19970304 I spent a lot of time on tuning transposition table code and
extensions. The program scores 78% at large Reinfeld's test set, 10 s
per move, on 486+/150.
II Two killer heuristics added: well known history killers (modified)
199704?? and `reaction' killers (the killer is connected to the previous enemy
move). The tree search is faster, especially at `quiet' positions.
Hashtable presearch. Modified hashentry replacement strategy. Better
evaluation function, it now knows more about passed pawns, the
endgame play is much stronger. Fixed bug at 7-th row pawn push
extension routine. Faster output - using sprintf() to prepare the
output and then only one printf. New command line options: -t, -T to
set the hashtable size.
III Permanent brain (pondering). King safety evaluation. Hung pieces
19970529 static evaluation. Null move pruning. Forward pruning. Better time
heuristics - forced moves are played quickly. New cmd-line options:
-f, -x, -p, -s.
IV New option -c to determine whether to use cpu or real time. The
19970721 internal timing resolution changed to 1/100 of a second. Xboard
compatible editing position. Removed en-passant capture from
quiescence search. Changes in static-eval function. Piece list
implemented - speedup is between 0 and 20%; more in endgame. Pinned
pieces static evaluation. Better evaluation of weak pawns. Trapped
bishop and knight evaluation. Bugfix at extending check evasions.
Bugfix: development bonus was computed but not added to total
evaluation. Output change: '!' means turn, '!!' means value out of
window.
V Mostly interface changes, no big improvement in playing strength.
19970803 Xboard compatibility fixes: 'post' is no more switch, new command
'remove'. Fixed command 'level': 'level 0 5 0' (five minutes per
game) should work, also increment (ICS) levels ('level 0 2 12').
Increment can be given at command line. New option -o (polling
input) - when running tests, phalanx needs -o-. New feature of
autotesting: all incorrect results are written into file
'notfound.fin'. Small output changes for better compatibility with
xboard 3.6.2. Eliminated some bad turns in evaluation. Better king
safety evaluation - counting safe checks available.
VI Fixed small efficiency bug in evaluate.c. Improved time heuristics
19970915 for increment (ICS) levels. Optimized hashing - about 5% overall
speedup. Fixed bug in ptime(). User is now allowed to continue play
even if the position is drawn by 3-rep., material, or 50 moves rule.
Fixed bug - Draw requests are now always ignored, not always accepted
:-). Xboard-compatible 'Illegal move' message. Binary opening book,
created from PGN by bcreate. This distribution is bigger than any
previous because it contains a small example of binary book
('sbook.phalanx', 174kB, 29634 moves). SAN input accepted. Static
evaluation now better understands middlegame positions without
castling. Added pre-computed tables into static evaluation -> about
5% speed improvement. 'Show thinking' mode now shows also a list of
book moves if there's a book entry. I have played a match with
previous version (64 games, 2 minutes, increment 12 seconds, on
a 486+/150, via xboard, no pondering), new version wins 38.5-25.5.
VII Courtesy of Pavel Janik ml., new command 'fen'. Bugfix in command
19971022 line parser, 'phalanx 0 2 12' now works. Better time controls: added
hard time limit to avoid being flagged. Pondering bugfix: Phalanx
was pondering O-O, but opponent played O-O-O; the move check was
incorrect and Phalanx thought that O-O was played; this resulted in
'Illegal move' message few moves later. More pondering safety: the
move to be pondered is now checked for legality, before this fix it
was simply taken from PV (if present), but PV is not always 100%
correct. More PV safety: search cannot be interrupted during the
first iteration, the abort is delayed until the first iteration is
finished. New options: -r <resign value>, -b <+/-> to set opening
book on/off. New commands hard/easy to set pondering on/off.
Optimized do_move(): 3% speedup in test positions. Search
optimization: null move is not played if the value in hash table
entry is too low. Output bugfix: output is now readable even at long
time searches. SEE (Static Exchange Evaluator) and more pruning in
quiescence search. RoboFICS compatible commands 'white' and 'black'.
Routine for evaluating pawn endgames. New extension trick that helps
in some horizon-effect type positions, it's based on measuring
difference between current score and null move result; if current
score is much better, the side to move must be under threat and the
line is extended, similar trick is also in gnuchess.
VIII Fixed bug in search(): eliminated useless re-searches -> about 3%
19971103 speed improvement. Noise level is now in centiseconds, not in nodes.
Improved horizon-effect extensions. endgame.c: new endgame
knowledge, mostly for endgames with minor pieces and pawns: knight
and bishop mating, knight+knight (draw), minor vs. minor (draw),
minor vs. pawn (draw, but still needs some work, sometimes a pawn
wins against a knight), onepawn() as a special case of pawns(), bad
bishop (bishop + rook pawn), basics for R+P vs. R, bishops with
opposite colors (this is often drawish ending). New penalty for
moving castling-side pawns in middlegame.
IX Function smove() is now used in both binary book and hashing code, it
19971205 is cleaner and easier to read, the binary is smaller with this.
Bugfix: Phalanx now does not ponder move that leads into a terminal
position (checkmate, stalemate), this fixes some unexpected quits
(I hope all of them). Added more limits to horizon-effect extension
trigger - there was so many extensions, that version VIII was
actually weaker than previous versions, because of lower nominal
search depth; these extensions are now used only for major threats.
Static eval cache entry is now packed into 4 bytes instead of 8 ->
the cache eats only 256K (512K before this).
X Bugfix in static evaluation of trapped knight at [AH]7. Better
19980108 evaluation of trapped bishop ([AH]7) and knight ([AH][87]), now it's
using the static exchange evaluator. Time allocation: alloc more
time (+1/8) if pondering is on. Better understanding of 'trade-down'
bonus - if there are no pawns, you often need a rook more to win the
game, a minor piece is not enough. Shallower extensions resulting in
greater average search depth. Easy levels: use new command line
option -e <1...100> to select an easy level; 1 is the strongest and
100 is the easiest one, Phalanx tries to make human-like blunders.
Minor changes in resigning. Clean up in pbook.phalanx, deleted over
100 positions. Killer heuristics now uses the SEE. Bugfix in
endgame.c: trade bonus did not work for kings and pawns endgames.
Simple learning, can be activated by -l+ option; it is off by
default, because it's very experimental version. New version wins
engine-engine match with version IX 23:17 (tc 2, inc 8, 486+/150,
no learning, no pondering).
XI Courtesy of Milan Zamazal: long options and user-friendly handling of
19980125 book files - you can now use environment variables or command line
options. Bugfix in trade bonus: endgame KQ-KBPP was evaluated only
about +1.10, but the stronger side is winnig here even without pawns,
now it's >+3.00 and Phalanx can solve this Dufrense&Mieses study:
8/3Np3/7P/1p3P2/1k6/5K2/1b6/8/w Pf5f6. Deeper overall extensions,
+10% of ply. More check evasion extensions. Wider window for 'lazy
evaluation', search is now slower but stable. Minor fixes in forward
and null move pruning. Zero-width search modified for root moves,
actually it's no more zero-width; this eliminates some 'blind turns'
(a move is evaluated as >=(Alpha+1), but the engine cannot prove it
in re-search in full [Alpha,Beta] window). Minor changes in static
evaluation. Bugfix in time allocation of increment levels. Changed
time heuristics to use more time.
XII More pruning in quiescence search: moves that have little chance to
19980301 return the value over alpha are not generated. Permanent brain is
now really 'permanent', if there is no move to ponder in the PV,
Phalanx uses short search to pick a move and ponders it. Bugfix:
occasional zero division at very fast time controls, like 10s/game.
Some puts() replaced with printf(), puts() is buggy in my gcc (2.7.2)
and causes sigsegv when interrupted and called again during the
interrupt. Optimized null move, this speeds up the engine. Easy
levels now use nodes instead of centiseconds for measuring time, the
playing strength of easy levels does not depend on cpu power and
cpu load. Resigning now works with RoboFics (via 'tellics resign').
Updated FSF address in docs.
XIII Lots of 'char' and 'short' replaced with 'int' -> speedup on iX86
19980316 chips (about 10% on my 486, probably more on P6). Bugfix at 'edit'
command, edit was broken for positions with black to move. New
command line option 'bench', 'phalanx bench' runs a 5 cpu-minutes
benchmark and reports nodes per second. Added some interesting lines
into the opening book. Dynamic draw score, it's set to -20 by
default. New command 'rating <phalanx rating> <opponent rating>' to
adjust the dynamic draw score, Phalanx tries to avoid draw with
weaker opponents, minimal draw score is -20, maximal +20.
XIV Dynamic draw score did not work for stalemate, now fixed. Major bug
19980416 fixed at resigning: if resigning was on, phalanx resigned almost any
game after few moves, this was broken from previous version.
Simplified computing bounds for lazy evaluation, this was too
complicated and slow. Higher material limit for evaluating position
as endgame. Deeper extensions, +0.1 ply. Improved move ordering at
root search. Minor optimizations. More variability in opening book.
Disabled scout search near leafs. Bugfix: type of Nodes changed to
'long long' (64 bits on Intel[3456]86), 32-bit integer was not long
enough for >24 hour runs. Bugfix: option -P did not work, now fixed.
Added startup messages that show full path of all open files.
XV Internal iterative deepening. Cleaned pbook.phalanx. New "Pc2-c4"
19980614 code to encourage playing c4 (c5 as black) in closed positions where
e4 (e5) is not possible. Bugfix at computing total material on the
board, the variable was sometimes overwritten with unexact value.
New xboard compatible commands 'bk' and 'analyze'. 'bk' shows all
book moves. 'analyze' starts analysis mode. Bugfix in bcreate.c: no
games on stdin caused segmentation fault. GNU extensions (long
options and snprintf) are now used only if GNUFUN is defined
(-DGNUFUN in makefile). New endgame knowledge: KNP vs. K is
sometimes draw. Small changes in static evaluation. SIGINT is
ignored in polling input mode. Time information in post lines is
shown in centiseconds instead of seconds to follow current draft of
xboard chess engine communication protocol.
XVI Bugfix in analyze mode: there is no extra character after the search
19980630 depth number in post lines - xboard understands that time info is in
centiseconds, not in seconds. Bugfix in null move pruning: the side
that is trying its second move in row must have at least one legal
move, this caused segmentation fault if there was none. Command
'hard' does not set pondering on in easy levels. Bugfix at parsing
SAN moves, nc3 was (possibly) interpreted as Pc2-c3. Command 'level'
accepts time in mm:ss form, for example 'level 0 2:30 12'. Bugfix in
kings+pawns endgames - penalty for pawns on one file (doubled) worked
as penalty for pawns on one row. Improved kings+pawns endgames
static evaluation. New command 'xboard' sets xboard compatible mode.
XVII More variability in pbook.phalanx. Better sbook.phalanx, generated
19980804 from wall.pgn. Changed (and fixed) extensions for check evasions and
passed pawn pushes. Changed evaluation of passed pawns. phalanx and
bcreate integrated into one binary, most of the code was common
anyway; book can be created via 'phalanx bcreate' instead of just
'bcreate'. Bigger limit for count of [position,move] in bcreate
code, the counter has 32 bits instead of 16. Performance bugfix in
null move pruning.
XVIII Bugfix in the static exchange evaluator - it let kings slide
19980906 horizontally. New styling of board in command "bd"/"d". New command
in edit mode: 's' to switch side to move. Modified look of edit
mode. Modifications in static evaluation: bishop pair needs
mobility; queen has 'king distance' bonus only if it's on a safe
square; simpler rook evaluations - smaller bonuses; forpost (outpost)
pawn gets more bonus for # of pieces defending it (Aaron Nimzowitsch,
"Mein System"); bigger bonus for protected or connected passed pawns.
Modified threat extensions - only mate threats are extended. Bugfix
in analysis mode: PV is computed (and shown) even if there is only
one legal move. New feature of command 'level' - 'level N' sets
level to N seconds fixed time per move. Better pbook.phalanx.
|
