[gnugo-devel] limit_search and restricted_genmove

[Arend Bayer]

We have two mechanisms to restrict search to a subset of the moves,
limit_search and restricted_genmove. This is not desirable, of course.

I suggest the following patch. It makes limit_search a private variable
of genmove.c. If genmove() finds it is set, do_genmove() is called with
the search_mask as list of allowed moves. Which means the rest of the engine
only has to worry about allowed_moves[].

Dan, since oracle is affected by this, it would be good if you could have
a look.

Arend


Index: engine/genmove.c
===================================================================
RCS file: /home/arend/Go/gnugo-rsync/gnugo/engine/genmove.c,v
retrieving revision 1.112
diff -u -p -r1.112 genmove.c
--- engine/genmove.c    25 Jan 2006 17:05:03 -0000      1.112
+++ engine/genmove.c    31 Jan 2006 23:38:16 -0000
@@ -36,6 +36,13 @@
  */
 #define NEEDS_UPDATE(x) (x != position_number ? (x = position_number, 1) : 0)
 
+/* Mark a limited search area. If limit_search != 1, genmove
+ * will only return moves within the area marked by the array
+ * search_mask.
+ */
+static int limit_search = 0;
+static int search_mask[BOARDMAX];
+
 static int do_genmove(int color, float pure_threat_value,
                      int allowed_moves[BOARDMAX], float *value, int *resign);
 
@@ -237,14 +244,17 @@ genmove(int color, float *value, int *re
 
 #if ORACLE
   if (metamachine) {
-    move = metamachine_genmove(color, value);
+    move = metamachine_genmove(color, value, limit_search);
     gg_assert(stackp == 0);
     if (move != PASS_MOVE)
       return move;
   }
 #endif
 
-  move = do_genmove(color, 0.4, NULL, value, resign);
+  if (limit_search)
+    move = do_genmove(color, 0.4, search_mask, value, resign);
+  else
+    move = do_genmove(color, 0.4, NULL, value, resign);
   gg_assert(move == PASS_MOVE || ON_BOARD(move));
 
   return move;
@@ -393,8 +403,7 @@ do_genmove(int color, float pure_threat_
   time_report(1, "generate move reasons", NO_MOVE, 1.0);
   
   /* Try to find empty corner moves. */
-  if (!limit_search)
-    fuseki(color);
+  fuseki(color);
   gg_assert(stackp == 0);
 
   /* Look for moves to break mirror play by the opponent. */
@@ -404,7 +413,7 @@ do_genmove(int color, float pure_threat_
    * dragon dangerous and change its status from DEAD to
    * UNKNOWN. Otherwise, pretend there is no thrashing dragon.
    */
-  if (!doing_scoring && !limit_search)
+  if (!doing_scoring)
     use_thrashing_dragon_heuristics
       = revise_thrashing_dragon(color, pessimistic_score, 5.0);
   
@@ -428,7 +437,7 @@ do_genmove(int color, float pure_threat_
 
 
   /* If the move value is 6 or lower, we look for endgame patterns too. */
-  if (*value <= 6.0 && !disable_endgame_patterns && !limit_search) {
+  if (*value <= 6.0 && !disable_endgame_patterns) {
     endgame_shapes(color);
     endgame(color);
     gg_assert(stackp == 0);
@@ -771,16 +780,14 @@ should_resign(int color, float optimisti
  *                Mark a limited search area                         *
 \*********************************************************************/
 
-/* Mark a limited search area. Only affects the engine if the
- * global variable limit_search is nonzero. In this case, genmove
- * will only return moves within the area marked by the array
- * search_mask.
- */
-
-static int search_mask[BOARDMAX];
+/* Activate or deactivate search limit. */
+void
+set_limit_search(int value)
+{
+  limit_search = value;
+}
 
-/* The following function marks a diamond of radius 6 with center pos.
- */
+/* The following function marks a diamond of radius 6 with center pos.  */
 
 void
 set_search_diamond(int pos)
@@ -812,7 +819,7 @@ reset_search_mask()
 /* marks a single vertex */
 
 void
-set_search_limit(int pos, int value)
+set_search_mask(int pos, int value)
 {
   search_mask[pos] = value;
 }
Index: engine/globals.c
===================================================================
RCS file: /home/arend/Go/gnugo-rsync/gnugo/engine/globals.c,v
retrieving revision 1.79
diff -u -p -r1.79 globals.c
--- engine/globals.c    23 Jan 2006 18:15:50 -0000      1.79
+++ engine/globals.c    31 Jan 2006 23:25:09 -0000
@@ -94,7 +94,6 @@ int debug             = 0;  /* controls 
 int verbose           = 0;  /* trace level */
 char outfilename[128] = ""; /* output file (-o option) */
 int output_flags      = OUTPUT_DEFAULT; /* amount of output to outfile */
-int limit_search      = 0;  /* limit search to a portion of the board */
 int metamachine       = 0;  /* use metamachine_genmove */
 int oracle_exists     = 0;  /* oracle is available for consultation   */
 int autolevel_on      = 0;  /* Adjust level in GMP or ASCII mode. */
Index: engine/gnugo.h
===================================================================
RCS file: /home/arend/Go/gnugo-rsync/gnugo/engine/gnugo.h,v
retrieving revision 1.132
diff -u -p -r1.132 gnugo.h
--- engine/gnugo.h      29 Jan 2006 18:36:59 -0000      1.132
+++ engine/gnugo.h      31 Jan 2006 23:25:22 -0000
@@ -239,7 +239,6 @@ extern int autolevel_on;
 
 extern float potential_moves[BOARDMAX];
 
-extern int limit_search;  /* limit move search to a portion of the board */
 extern int oracle_exists; /* oracle is available for consultation        */
 extern int metamachine;   /* use metamachine_genmove                     */
 
Index: engine/liberty.h
===================================================================
RCS file: /home/arend/Go/gnugo-rsync/gnugo/engine/liberty.h,v
retrieving revision 1.252
diff -u -p -r1.252 liberty.h
--- engine/liberty.h    25 Jan 2006 17:14:04 -0000      1.252
+++ engine/liberty.h    31 Jan 2006 23:39:48 -0000
@@ -499,9 +499,10 @@ void owl_analyze_semeai_after_move(int m
                                   int *semeai_result_certain,
                                   int recompute_dragons);
 
+void set_limit_search(int value);
 void set_search_diamond(int pos);
 void reset_search_mask(void);
-void set_search_limit(int pos, int value);
+void set_search_mask(int pos, int value);
 int oracle_play_move(int pos, int color);
 void consult_oracle(int color);
 void summon_oracle(void);
Index: engine/move_reasons.c
===================================================================
RCS file: /home/arend/Go/gnugo-rsync/gnugo/engine/move_reasons.c,v
retrieving revision 1.133
diff -u -p -r1.133 move_reasons.c
--- engine/move_reasons.c       23 Jan 2006 18:15:50 -0000      1.133
+++ engine/move_reasons.c       31 Jan 2006 23:25:45 -0000
@@ -362,8 +362,6 @@ add_move_reason(int pos, int type, int w
   if (stackp == 0) {
     ASSERT1(board[pos] == EMPTY, pos);
   }
-  if (limit_search && !within_search_area(pos))
-    return;
 
   for (k = 0; k < MAX_REASONS; k++) {
     int r = move[pos].reason[k];
Index: engine/oracle.c
===================================================================
RCS file: /home/arend/Go/gnugo-rsync/gnugo/engine/oracle.c,v
retrieving revision 1.18
diff -u -p -r1.18 oracle.c
--- engine/oracle.c     23 Jan 2006 18:15:50 -0000      1.18
+++ engine/oracle.c     31 Jan 2006 23:27:09 -0000
@@ -342,7 +342,7 @@ static int
 do_metamachine_genmove(int color, int width, float *value);
 
 int
-metamachine_genmove(int color, float *value)
+metamachine_genmove(int color, float *value, int limit_search)
 {
   int move;
   int pos;
Index: engine/shapes.c
===================================================================
RCS file: /home/arend/Go/gnugo-rsync/gnugo/engine/shapes.c,v
retrieving revision 1.53
diff -u -p -r1.53 shapes.c
--- engine/shapes.c     23 Jan 2006 18:15:50 -0000      1.53
+++ engine/shapes.c     31 Jan 2006 23:25:56 -0000
@@ -233,10 +233,6 @@ shapes_callback(int anchor, int color, s
   /* Pick up the location of the move */
   move = AFFINE_TRANSFORM(pattern->move_offset, ll, anchor);
 
-  /* For restricted search, the pattern must intersect the search area */
-  if (limit_search && !within_search_area(move))
-    return;
-
   /* For some classes of patterns we need to find all dragons present
    * in the pattern.
    */
@@ -538,10 +534,6 @@ joseki_callback(int move, int color, str
   int your_dragons[MAX_DRAGONS_PER_PATTERN];
   int your_ndragons = 0;
 
-  /* For restricted search, the pattern must intersect the search area. */
-  if (limit_search && !within_search_area(move))
-    return;
-
   /* For urgent joseki patterns we need to find all dragons present in the
    * pattern since such patterns are assumed to have strategical effect on
    * them.
Index: interface/play_gtp.c
===================================================================
RCS file: /home/arend/Go/gnugo-rsync/gnugo/interface/play_gtp.c,v
retrieving revision 1.179
diff -u -p -r1.179 play_gtp.c
--- interface/play_gtp.c        29 Jan 2006 18:36:59 -0000      1.179
+++ interface/play_gtp.c        31 Jan 2006 23:39:19 -0000
@@ -255,7 +255,6 @@ static struct gtp_command commands[] = {
   {"last_move",              gtp_last_move},
   {"level",                  gtp_set_level},
   {"limit_search",                   gtp_limit_search},
-  {"limit_search",            gtp_limit_search},
   {"list_commands",                  gtp_list_commands},
   {"list_stones",            gtp_list_stones},
   {"loadsgf",                        gtp_loadsgf},
@@ -4481,7 +4480,7 @@ gtp_set_search_diamond(char *s)
   if (!gtp_decode_coord(s, &i, &j))
     return gtp_failure("invalid coordinate");
   
-  limit_search = 1;
+  set_limit_search(1);
   set_search_diamond(POS(i, j));
   return gtp_success("");
 }
@@ -4512,7 +4511,7 @@ gtp_limit_search(char *s)
 
   if (sscanf(s, "%d", &value) < 1)
     return gtp_failure("invalid value for search limit");
-  limit_search = value;
+  set_limit_search(value);
   return gtp_success("");
 }
 
@@ -4527,7 +4526,7 @@ gtp_set_search_limit(char *s)
   int i, j;
 
   gtp_decode_coord(s, &i, &j);
-  set_search_limit(POS(i, j), 1);
+  set_search_mask(POS(i, j), 1);
   return gtp_success("");
 }