Version 0.9.4

=============
Corrected undo bug
Added iterative deepening

src/suicideChess/ComputerPlayer.java

@@ -142,10 +142,13 @@ public class ComputerPlayer {
         nodesSearched = 0;
 
         thinkingBeginingTime = new Date();
-
+        quiescenceSearch = false;
         //iterative deepening
         for(maxDepth=2; maxDepth<=SuicideChess.getPlyDepth(); maxDepth++) {
-            ReturnWrapper bestScore = AlphaBeta(bitboard, 0, Board.MIN_VALUE, Board.MAX_VALUE);
+            if(SuicideChess.QUIESCENCE_SEARCH && maxDepth==SuicideChess.getPlyDepth()) {
+                quiescenceSearch = true; //don't do quiescence search till the last level iterative deepening
+            }
+            ReturnWrapper bestScore = AlphaBeta(bitboard, 0, maxDepth, Board.MIN_VALUE, Board.MAX_VALUE);
             Date thinkingEndTime = new Date();
             
             //select one of the best moves randomly
@@ -174,6 +177,7 @@ public class ComputerPlayer {
         return bestMove;
     }
     
+    private static boolean quiescenceSearch; //this will be used to determine is quiescence search is needed. 
     private static Date thinkingBeginingTime;
     private static int maxDepth;
     private static ArrayList<Move> bestMoves=new ArrayList<Move>();
@@ -194,33 +198,33 @@ public class ComputerPlayer {
         public int getBranchValue() {return this.branchValue;}
         public String getPrincipalVariation() {return this.principalVariation;}
     };
-    private static ReturnWrapper AlphaBeta(Board bitboard, int currentDepth, int alpha, int beta) throws NotAValidSquare, NoPieceOnSquare {
+    private static ReturnWrapper AlphaBeta(Board bitboard, int currentDepth, int currentMaxDepth, int alpha, int beta) throws NotAValidSquare, NoPieceOnSquare {
         nodesSearched++;
-        int currentMaxDepth = maxDepth; //this is when intelligent depth is on, the computer may search one step further
 
-        if(!SuicideChess.QUIESCENCE_SEARCH || currentMaxDepth>=SuicideChess.MAX_PLY_DEPTH) { //stop if we are getting to deep
         if(bitboard.isADraw()) {
             return new ReturnWrapper(Board.DRAW_BOARD,Board.DRAW_BOARD,"");
         }
-            if (currentDepth >= currentMaxDepth) {
+
+        if((!quiescenceSearch)&& (currentDepth >= currentMaxDepth)) { //stop if we are getting to deep
             //System.out.println("'-> Evaluate: "+bitboard.getBoardValue());
             return new ReturnWrapper(bitboard.getBoardValue(),bitboard.getBoardValue(),"");
         }
-        }
         Rules.legalMovesForPlayer(bitboard);
         ArrayList<Move> allLegalMoves = Rules.getLegalMovesCapture();
         if (allLegalMoves.size()==0) {
-            if(SuicideChess.QUIESCENCE_SEARCH) {
+            if((quiescenceSearch) && (currentDepth >= currentMaxDepth)) {
-                if(bitboard.isADraw()) {
-                    return new ReturnWrapper(Board.DRAW_BOARD,Board.DRAW_BOARD,"");
-                }
-                if (currentDepth >= currentMaxDepth) {
                 //System.out.println("'-> Evaluate: "+bitboard.getBoardValue());
                 return new ReturnWrapper(bitboard.getBoardValue(),bitboard.getBoardValue(),"");
             }
-            }
             allLegalMoves = Rules.getLegalMovesNonCapture();
         } else { //if there are captures, see if we can just abandon search here
+            if((quiescenceSearch) && (currentDepth >= currentMaxDepth)) {
+                if((currentMaxDepth<SuicideChess.MAX_PLY_DEPTH) && (allLegalMoves.size()<=SuicideChess.QUIESCENCE_LIMIT)) {
+                    currentMaxDepth++;
+                } else {
+                    return new ReturnWrapper(bitboard.getBoardValue(),bitboard.getBoardValue(),"");
+                }
+            }
             if (SuicideChess.INTELLIGENT_DEPTH) {
                 currentMaxDepth++; //go one step further in depth
                 if(currentDepth==0 && allLegalMoves.size()==1) {
@@ -256,7 +260,7 @@ public class ComputerPlayer {
                     
                     //System.out.println("Analysing "+currentDepth+":"+allLegalMoves.get(i));
                     
-                    ReturnWrapper returnValue = AlphaBeta(boardCopy,currentDepth+1,Board.MIN_VALUE,beta);
+                    ReturnWrapper returnValue = AlphaBeta(boardCopy,currentDepth+1,currentMaxDepth,Board.MIN_VALUE,beta);
                     currentScore = returnValue.getBranchValue();
                     currentAlphaBeta = returnValue.getAlphaBeta();
                     
@@ -307,7 +311,7 @@ public class ComputerPlayer {
                     
                     //System.out.println("Analysing "+currentDepth+":"+allLegalMoves.get(i));
                     
-                    ReturnWrapper returnValue = AlphaBeta(boardCopy,currentDepth+1,alpha,Board.MAX_VALUE);
+                    ReturnWrapper returnValue = AlphaBeta(boardCopy,currentDepth+1,currentMaxDepth,alpha,Board.MAX_VALUE);
                     currentScore = returnValue.getBranchValue();
                     currentAlphaBeta = returnValue.getAlphaBeta();
                     

src/suicideChess/SuicideChess.java

@@ -47,7 +47,7 @@ public class SuicideChess {
     /**
      * Quiescence search -> don't evaluate if captures are possible.
      */
-    public static final boolean QUIESCENCE_SEARCH = false;
+    public static final boolean QUIESCENCE_SEARCH = true;
     
     /**
      * The name to be displayed
@@ -82,6 +82,10 @@ public class SuicideChess {
      * Maximum number of Plies the computer will ever go to
      */
     public static final int MAX_PLY_DEPTH = 8;
+    /**
+     * Quiescence limit (ie. if more than that many possibilities of capturing, don't analyse further.
+     */
+    public static final int QUIESCENCE_LIMIT = 5;
     
     /**
      * Test and display if the board is in a winning state.
@@ -127,6 +131,7 @@ public class SuicideChess {
      * This function is used to undo the last position played 
      */
     private static Board removePlayedPosition () {
+        if(allPlayedPositions.size()>1)
             allPlayedPositions.remove(0);
         return allPlayedPositions.get(0);
     }
@@ -204,6 +209,7 @@ public class SuicideChess {
                     System.out.println("remove\t\t\tundoes a full move");
                     System.out.println("force\t\t\tthe computer will check moves but not play");
                     System.out.println();
+                    System.out.println("board\t\t\tdisplays the current status of the board");
                     System.out.println("setboard FEN\t\tsets the board according to the FEN position");
                     System.out.println("sd N\t\t\tsets the search depth to n");
                     System.out.println("bk\t\t\tdisplays available openbook moves for current position");
@@ -396,6 +402,7 @@ public class SuicideChess {
                                     //allLegalMoves.get(foundMoveIndex).display();
                                     //System.out.println("Board value: "+bitboard.getBoardValue());
                                     bitboard.display();
+                                    displayPlayer(bitboard);
                                 }
                                 playedALegalMove=true;
                             }