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I got the following problem. I have implemented transposition tables, which seem to work well or at least I can not see they are not working.

Additionally, I wanted to implement some move-ordering.

Basically, I search the move first that's saved in my transposition table. For some reason, that doesn't improve the search at all. Either I haven't implemented move-ordering properly or my implementation of the alpha-beta algorithm along with transposition tables is just wrong.

To measure the performance I counted the number of nodes visited during search. My implementation of move-ordering didn't have any effect at all.

Here is the Java-Code I have come up with:

public  int alphabeta(final CheckerBoard board,int alpha,int beta,int depth,boolean nullMoveAvailable){
  nodeCount++;

 int alphaOrig=alpha;
    Transposition entry =table.find(board.key);
    if(entry!=null && entry.depth>=depth){
        if(entry.flag==Transposition.EXACT){
            return entry.value;
        }else if(entry.flag==Transposition.UPPER){
            beta = Math.min(beta,entry.value);
        }else if(entry.flag == Transposition.LOWER){
            alpha =Math.max(alpha,entry.value);
        }
        if(alpha>=beta){
            return entry.value;
        }
    }

    if(depth==0 || board.isTerminalState()){
        return quiesceneSearch2(board,alpha,beta);
    }

ArrayList<Move>sucessors =MGenerator.getMoves(board);
Move currentBest =null;
for( int i=0;i<sucessors.size();i++){
        if(entry!=null && entry.depth<depth && (entry.flag == Transposition.UPPER || entry.flag == Transposition.EXACT) &&  sucessors.get(i).equals(entry.best)){
          Collections.swap(sucessors,0,i);
            break;
        }
    }

    int bestValue =Integer.MIN_VALUE;
    for(Move  move : sucessors){
        board.makeMove(move);
        int value =-alphabeta(board, -beta, -alpha, depth - 1, true);
        board.undoMove(move);
        if(value>bestValue){
            bestValue =value;
            currentBest = move;
        }
        alpha =Math.max(alpha,value);
        if(alpha>=beta){
            break;
        }
    }

    Transposition next =new Transposition();
    next.depth=depth;
    next.value =bestValue;
    next.zobrisKey=board.key;
    next.best = currentBest;
    if(bestValue<=alphaOrig){
        next.flag =Transposition.UPPER;
    }else if(bestValue>=beta){
        next.flag = Transposition.LOWER ;
    }else{
        next.flag = Transposition.EXACT;

    }
    table.insert(next);

    return alpha;
}

and the following code to start the search:

    public int findBestMove(int depth){
    if (table != null) {
        table.clear();
    }
    ArrayList<Move> sucessors =MGenerator.getMoves(board);
    int max = Integer.MIN_VALUE;
    for(Move m : sucessors){
        board.makeMove(m);
        int value =-alphabeta(board, -1000000, 1000000, depth, true);
        board.undoMove(m);
        if(value>max){
            max=value;
            bestMove=m;
        }
    }

    board.makeMove(bestMove);
    return max;
}

Would appreciate it if someone looked at my code. Maybe there isn't anything wrong with this part of my code but I didn't want to post everything since it's already quite a lot of code to look at.

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