rollout evaluation function

uttt.c

@@ -786,8 +786,8 @@ int ut_boardValue(const char *tiles, int offset, int stride)
 			value += (T(r, c) == 'X') ? 1 : (T(r, c) == 'O') ? -1 : 0;
 	return value;
 }
-#define UT_VALUEMAX 81 * 2
-#define UT_VALUEMIN (-81 * 2)
+#define UT_VALUEMAX 81
+#define UT_VALUEMIN (-81)
 int ut_value(const struct ut_state *state)
 {
 	int value = 0;
@@ -796,12 +796,12 @@ int ut_value(const struct ut_state *state)
 	char winner = ut_winner(state);
 	if(winner != '\0')
 	{
-		return (winner == 'X') ? 81 * 2 : (winner == 'O') ? -81 * 2 : 0;
+		return (winner == 'X') ? UT_VALUEMAX : (winner == 'O') ? UT_VALUEMIN : 0;
 	}
 
 	// weight each board: 2x if taken, 2x if blank but would lead to a 2-of-3
 	// line (for X or O), 1x otherwise
-	char importance[3][3] = {1};
+	/*char importance[3][3] = {1};
 	for(int r = 0; r < 3; r++) {
 		for(int c = 0; c < 3; c++) {
 			char board = state->boards[r][c];
@@ -834,7 +834,7 @@ int ut_value(const struct ut_state *state)
 			else if (board == 'X') importance[r][c] = 2;
 			else if (board == 'O') importance[r][c] = 2;
 		}
-	}
+	}*/
 
 	// game is in progress
 	for(int r = 0; r < 3; r++) {
@@ -848,19 +848,19 @@ int ut_value(const struct ut_state *state)
 				// board is won
 				board_value = (board == 'X') ? 9 : (board == 'O') ? -9 : 0;
 			}
-			value += board_value * importance[r][c];
+			value += board_value/* * importance[r][c]*/;
 		}
 	}
 
 	return value;
 }
 
-int ut_alphabetaq(const struct ut_state *state, struct ut_move move, int depth, int a, int b)
+int ut_alphabetaq(int (*value)(const struct ut_state *state), const struct ut_state *state, struct ut_move move, int depth, int a, int b)
 {
 	struct ut_state next;
 	if(ut_move(&next, state, move)) {return (state->player == 'X') ? UT_VALUEMIN - 1 : UT_VALUEMAX + 1;}
 
-	int q = ut_value(&next);
+	int q = value(&next);
 	if(depth <= 0 || q <= UT_VALUEMIN || q >= UT_VALUEMAX) {return q;}
 
 
@@ -871,7 +871,7 @@ int ut_alphabetaq(const struct ut_state *state, struct ut_move move, int depth,
 		for(int c = 0; c < 9; c++)
 		{
 			struct ut_move next_move = (struct ut_move){r, c};
-			int next_q = ut_alphabetaq(&next, next_move, depth - 1, a, b);
+			int next_q = ut_alphabetaq(value, &next, next_move, depth - 1, a, b);
 			if(next_q > q) {q = next_q;}
 			if(q > b) {return q;}
 			a = q > a ? q : a;
@@ -884,7 +884,7 @@ int ut_alphabetaq(const struct ut_state *state, struct ut_move move, int depth,
 		for(int c = 0; c < 9; c++)
 		{
 			struct ut_move next_move = (struct ut_move){r, c};
-			int next_q = ut_alphabetaq(&next, next_move, depth - 1, a, b);
+			int next_q = ut_alphabetaq(value, &next, next_move, depth - 1, a, b);
 			if(next_q < q) {q = next_q;}
 			if(q < a) {return q;}
 			b = q < b ? q : b;
@@ -892,8 +892,8 @@ int ut_alphabetaq(const struct ut_state *state, struct ut_move move, int depth,
 	}
 	return q;
 }
-#define UT_DEPTH 6
-struct ut_move ut_minimax(const struct ut_state *state)
+
+struct ut_move ut_minimax(int (*value)(const struct ut_state *state), const struct ut_state *state, int depth)
 {
 	struct ut_move best_move = {-1, -1};
 	int best_q = (state->player == 'X') ? UT_VALUEMIN - 1 : UT_VALUEMAX + 1;
@@ -901,7 +901,7 @@ struct ut_move ut_minimax(const struct ut_state *state)
 	for(int c = 0; c < 9; c++)
 	{
 		struct ut_move move = (struct ut_move){r, c};
-		int q = ut_alphabetaq(state, move, UT_DEPTH - 1, UT_VALUEMIN - 1, UT_VALUEMAX + 1);
+		int q = ut_alphabetaq(value, state, move, depth - 1, UT_VALUEMIN - 1, UT_VALUEMAX + 1);
 		if((state->player == 'X') ? q > best_q : q < best_q)
 		{
 			best_q = q;
@@ -911,8 +911,28 @@ struct ut_move ut_minimax(const struct ut_state *state)
 	return best_move;
 }
 
+#define UT_RDEPTH 1
+int ut_rollout(const struct ut_state *state)
+{
+
+	struct ut_state rstate = *state;
+	int moves = 0;
+	char winner;
+	while((winner = ut_winner(&rstate)) == '\0')
+	{
+		if(ut_move(&rstate, &rstate,
+			   ut_minimax(ut_value, &rstate, UT_RDEPTH)))
+		{
+			return 0;
+		}
+		moves++;
+	}
+	return (winner == 'X') ? (UT_VALUEMAX - moves) : (winner == 'O') ? (UT_VALUEMIN + moves) : 0;
+}
+
+#define UT_DEPTH 5
 int ut_agentgetmove(const struct ut_state *state, const struct ut_game *game, struct ut_move *move)
 {
-	*move = ut_minimax(state);
+	*move = ut_minimax(ut_rollout, state, UT_DEPTH);
 	return (move->r < 0 || move->r >= 9 || move->c < 0 || move->c >= 9);
 }