improve connection games

src/evaluate.cpp

@@ -1281,8 +1281,17 @@ namespace {
     }
 
     // Connect-n
-    if (pos.connect_n() > 0)
+    if (pos.connect_n() > 0 && (pos.variant()->connectValue != VALUE_DRAW))
     {
+        //Calculate eligible pieces for connection once.
+        //Still consider all opponent pieces as blocking.
+        Bitboard connectPiecesUs = 0;
+        for (PieceSet ps = pos.connect_piece_types(); ps;){
+            PieceType pt = pop_lsb(ps);
+            connectPiecesUs |= pos.pieces(pt);
+        };
+        connectPiecesUs &= pos.pieces(Us);
+
         for (const Direction& d : pos.getConnectDirections())
 
         {
@@ -1296,9 +1305,10 @@ namespace {
                 Square s = pop_lsb(b);
                 int c = 0;
                 for (int j = 0; j < pos.connect_n(); j++)
-                    if (pos.pieces(Us) & (s - j * d))
+                    if (connectPiecesUs & (s - j * d))
                         c++;
-                score += make_score(200, 200)  * c / (pos.connect_n() - c) / (pos.connect_n() - c);
+                score += (pos.variant()->connectValue==VALUE_MATE ? 1 : -1) * //At least change the sign for misere variants.
+                             (make_score(200, 200)  * c / (pos.connect_n() - c) / (pos.connect_n() - c));
             }
         }
     }

src/position.cpp

@@ -2801,7 +2801,7 @@ bool Position::is_immediate_game_end(Value& result, int ply) const {
   connectPieces &= pieces(~sideToMove);
 
   // Connect-n
-  if (connect_n() > 0)
+  if ((connect_n() > 0) && (popcount(connectPieces) >= connect_n()))
   {
       Bitboard b;
 
@@ -2843,8 +2843,8 @@ bool Position::is_immediate_game_end(Value& result, int ply) const {
           current |= newBitboard;
       }
   }
-  
-  if (connect_nxn())
+
+  if ((connect_nxn()) && (popcount(connectPieces) >= connect_nxn() * connect_nxn()))
   {
       Bitboard connectors = connectPieces;
       for (int i = 1; i < connect_nxn() && connectors; i++)
@@ -2857,28 +2857,45 @@ bool Position::is_immediate_game_end(Value& result, int ply) const {
   }
 
   // Collinear-n
-  if (collinear_n() > 0) {
-      Bitboard allPieces = connectPieces;
-      for (Direction d : var->connect_directions) {
-          Bitboard b = allPieces;
-          while (b) {
-              Square s = pop_lsb(b);
-
-              int total_count = 1; // Start with the current piece
-
-              // Check in both directions
-              for (int sign : {-1, 1}) {
-                  Bitboard shifted = shift(sign * d, square_bb(s));
-                  while (shifted) {
-                      if (shifted & b) {
-                          total_count++;
-                          b &= ~shifted; // Remove this piece from further consideration
-                      }
-                      shifted = shift(sign * d, shifted);
-                  }
-              }
+  if ((collinear_n() > 0) && (popcount(connectPieces) >= collinear_n())) {
+      Bitboard pieces = connectPieces;
+      while (pieces) {
+
 
-              if (total_count >= collinear_n()) {
+/*
+          //can't combine this with the (!is_ok(shifted_square)) optimization below
+          //if it relies on there being another piece to count it as part of its line,
+          //can't early out.
+          if (popcount(pieces) < collinear_n()) {
+              break; // Early out to the next section
+          }
+*/
+          //Use pop_lsb to loop through the pieces. Then for each of the directions,
+          //use line_bb to calculate the entire row, column or diagonal that contains
+          //the piece and the shifted square, then use popcount to count the number
+          //of pieces on that line.
+          Square s = pop_lsb(pieces);
+          for (Direction d : var->connect_directions) {
+              Square shifted_square = s + d;
+
+
+              if (!is_ok(shifted_square)) continue; //This is totally fine.
+              //Pieces where the shift is outside the board will not be processed
+              //for that direction, but in order to be collinear with another piece,
+              //there would be another piece that counts it as part of its line.
+              //Even if say, all the pieces were on the EAST edge, it's the NORTH
+              //direction that would count them up.
+              //Only exception is that if collinearN was set to 1, and there was 1
+              //piece on the NORTH_EAST corner, it wouldn't count. Possible solutions:
+              //1. Ignore
+              //2. Tell user that collinearN=1 is silly, use flagPieces or connectN
+              //3. Special case here to check
+              //4. Quietly convert it to connectN=1
+
+
+              Bitboard line = line_bb(s, shifted_square);
+              int piece_count = popcount(line & connectPieces);
+              if (piece_count >= collinear_n()) {
                   result = convert_mate_value(-var->connectValue, ply);
                   return true;
               }
@@ -2887,7 +2904,7 @@ bool Position::is_immediate_game_end(Value& result, int ply) const {
   }
 
   // Check for bikjang rule (Janggi), double passing, or board running full
-  if (   (st->pliesFromNull > 0 && ((st->bikjang && st->previous->bikjang) || (st->pass && st->previous->pass)))
+  if (   (st->pliesFromNull > 0 && ((st->bikjang && st->previous->bikjang) || ((st->pass && st->previous->pass)&&!var->wallOrMove)))
       || (var->adjudicateFullBoard && !(~pieces() & board_bb())))
   {
       result = var->materialCounting ? convert_mate_value(material_counting_result(), ply) : VALUE_DRAW;

src/position.h

@@ -1039,7 +1039,7 @@ inline int Position::connect_n() const {
 
 inline PieceSet Position::connect_piece_types() const {
   assert(var != nullptr);
-  return var->connectPieceTypes;
+  return var->connectPieceTypesTrimmed;
 }
 
 inline bool Position::connect_horizontal() const {

src/variant.cpp

@@ -2066,15 +2066,16 @@ Variant* Variant::conclude() {
         connect_directions.push_back(SOUTH_EAST);
     }
 
-    // If not a connect variant, set connectPieceTypes to no pieces.
+    // If not a connect variant, set connectPieceTypesTrimmed to no pieces.
+    // connectPieceTypesTrimmed is separated so that connectPieceTypes is left unchanged for inheritance.
     if ( !(connectRegion1[WHITE] || connectRegion1[BLACK] || connectN || connectNxN || collinearN) )
     {
-          connectPieceTypes = NO_PIECE_SET;
+          connectPieceTypesTrimmed = NO_PIECE_SET;
     }
     //Otherwise optimize to pieces actually in the game.
     else
     {
-        connectPieceTypes = connectPieceTypes & pieceTypes;
+        connectPieceTypesTrimmed = connectPieceTypes & pieceTypes;
     };
 
     return this;

src/variant.h

@@ -178,6 +178,7 @@ struct Variant {
   bool endgameEval = false;
   bool shogiStylePromotions = false;
   std::vector<Direction> connect_directions;
+  PieceSet connectPieceTypesTrimmed = ~NO_PIECE_SET;
 
   void add_piece(PieceType pt, char c, std::string betza = "", char c2 = ' ') {
       // Avoid ambiguous definition by removing existing piece with same letter