/** * The heuristic evaluation function that determines the chances of winning... * * @param brd board to be evaluated * @return score that indicates our chances of winning */ protected static int evalBoard(BreakthroughState brd) { int score = 0; for (int r = 0; r < BreakthroughState.N; r++) { for (int c = 0; c < BreakthroughState.N; c++) { if (brd.board[r][c] == BreakthroughState.homeSym) { score += (r + 1); } else if (brd.board[r][c] == BreakthroughState.awaySym) { score -= (BreakthroughState.N - r); } } } if (Math.abs(score) > MAX_EVAL_SCORE) { System.err.println("Problem with eval"); System.exit(0); } return score; }
public void alphabetaTT(char[][] map, int d, double a, double b, boolean isHome, Move[] stack) { double ev_tem = 0; ev_tem = ev2(map, isHome); if (d == MAX_DEPTH || Math.abs(ev_tem) == MAX_SCORE) { stack[d].score = ev_tem; return; } Board board = new Board(map, isHome, "alphabetatt"); TTEntry tte = tt.getEntry(board.getHashKey()); if (tte != null && tte.getDepth() <= d) { if (tte.getType() == TTEntry.NT.EXACT) { stack[d].score = tte.getScore(); return; } if (tte.getType() == TTEntry.NT.LOWERBOUND && tte.getScore() > a) a = tte.getScore(); else if (tte.getType() == TTEntry.NT.UPPERBOUNT && tte.getScore() < b) b = tte.getScore(); if (a >= b) { stack[d].score = tte.getScore(); return; } } if (board.getSize() == 0) System.out.println(isHome + "\t" + d); Move move; if (isHome) { double v = Double.NEGATIVE_INFINITY; while (board.hasNext()) { if (FIRST_LAYER_DEBUG == 1 && d == 0) System.out.println("Home: 0 Total: " + board.getSize()); move = board.next(); map[move.row1][move.col1] = homeSym; map[move.row2][move.col2] = homeSym; if (d + 1 == MAX_DEPTH) { stack[d + 1].set(move.row1, move.col1, move.row2, move.col2); } alphabetaTT(map, d + 1, a, b, false, stack); if (stack[d + 1].score > v) { v = stack[d + 1].score; stack[d].set(move.row1, move.col1, move.row2, move.col2, v); } map[move.row1][move.col1] = emptySym; map[move.row2][move.col2] = emptySym; a = Math.max(a, stack[d].score); if (stack[d].score >= b || stack[d].score == MAX_SCORE) return; } if (stack[d].score < a) tt.store(new TTEntry(board.getHashKey(), stack[d].score, TTEntry.NT.LOWERBOUND, d)); else if (stack[d].score > b) tt.store(new TTEntry(board.getHashKey(), stack[d].score, TTEntry.NT.UPPERBOUNT, d)); return; } else { double v = Double.POSITIVE_INFINITY; while (board.hasNext()) { if (FIRST_LAYER_DEBUG == 1 && d == 0) System.out.println("Away: 0 Total: " + board.getSize()); move = board.next(); map[move.row1][move.col1] = awaySym; map[move.row2][move.col2] = awaySym; if (d + 1 == MAX_DEPTH) { stack[d + 1].set(move.row1, move.col1, move.row2, move.col2); } alphabetaTT(map, d + 1, a, b, true, stack); if (stack[d + 1].score < v) { v = stack[d + 1].score; stack[d].set(move.row1, move.col1, move.row2, move.col2, v); } map[move.row1][move.col1] = emptySym; map[move.row2][move.col2] = emptySym; b = Math.min(b, stack[d].score); if (stack[d].score <= a || stack[d].score == -MAX_SCORE) return; } if (stack[d].score < a) tt.store(new TTEntry(board.getHashKey(), stack[d].score, TTEntry.NT.LOWERBOUND, d)); else if (stack[d].score > b) tt.store(new TTEntry(board.getHashKey(), stack[d].score, TTEntry.NT.UPPERBOUNT, d)); return; } }