Small changes to build ct1986

1 files changed, 17 insertions, 26 deletions

diff --git a/include/negamax.c b/include/negamax.c
index 7f05040..061b629 100644
--- a/include/negamax.c
+++ b/include/negamax.c
@@ -93,20 +93,6 @@ negamax_free(void) {
 	zobrist_free();
 }
 
-static enum WIN_TYPE w;
-
-static inline float
-negamax_evaluate_terminal(const float colour) {
-	if (ply >= 2*board_size - 2 && (w = check_win()) < 0xFF) {
-		// Check win if far enough into the game
-		if (w == WIN_ROAD_BLACK || w == WIN_FLAT_BLACK) return colour*infty;
-		else if (w == WIN_DRAW) return 0; // Draw is fixed at neutral
-		else return -colour*infty;
-	} else {
-		return colour * cnn1986_evaluate_black_win();
-	}
-}
-
 float
 negamax_generate(void) {
 	// We need to start with something outside of [-∞,∞] because those
@@ -123,6 +109,7 @@ negamax_generate(void) {
 }
 
 static enum TT_FLAG flag;
+static enum WIN_TYPE w;
 
 static float
 negamax(const uint8_t cur_depth, float alpha, float beta,
@@ -151,8 +138,9 @@ negamax(const uint8_t cur_depth, float alpha, float beta,
 		action_move_to_front(entry->action, list);
 	}
 
-	action_t best_action;
-	float value = -infty;
+	// TODO: what to do if this is never written to?
+	action_t best_action = list->head->action;
+	float best_value = -infty;
 
 	for (action_node_t *node=list->head; node!=NULL; node=node->next) {
 
@@ -162,8 +150,11 @@ negamax(const uint8_t cur_depth, float alpha, float beta,
 		if (ply >= 2*board_size - 2 && (w = check_win()) < 0xFF) {
 			node_value = -colour*infty;
 			// Check win if far enough into the game
-			if (w == WIN_ROAD_BLACK || w == WIN_FLAT_BLACK) node_value = colour*infty;
-			else if (w == WIN_DRAW) node_value = 0; // Draw is neutral
+			if (w == WIN_ROAD_BLACK || w == WIN_FLAT_BLACK) {
+				node_value = colour*infty;
+			} else if (w == WIN_DRAW) {
+				node_value = 0;
+			}
 		} else if (cur_depth > 1) {
 			// If nobody won, or too early and not leaf, recurse
 			node_value = -negamax(cur_depth - 1, -beta, -alpha, -colour);
@@ -174,31 +165,31 @@ negamax(const uint8_t cur_depth, float alpha, float beta,
 
 		negamax_display_progress(cur_depth, list->length);
 
-		if (node_value > value) {
-			value = node_value;
+		if (node_value > best_value) {
+			best_value = node_value;
 			best_action = node->action;
 			if (cur_depth == negamax_search_depth)
 				action_to_ptn(node->action, negamax_ptn);
 		}
 
-		alpha = fmax(value, alpha);
+		alpha = fmax(best_value, alpha);
 		if (alpha >= beta) break;
 	}
 
 	action_list_free(list);
 
 	flag = TT_EXACT;
-	if (value >= beta) flag = TT_LOWERBOUND;
-	else if (value <= alpha) flag = TT_UPPERBOUND;
+	if (best_value >= beta) flag = TT_LOWERBOUND;
+	else if (best_value <= alpha) flag = TT_UPPERBOUND;
 
 	if (entry == NULL) {
-		tt_insert(hash, flag, cur_depth, value, best_action);
+		tt_insert(hash, flag, cur_depth, best_value, best_action);
 	} else {
 		entry->flag = flag;
-		entry->value = value;
+		entry->value = best_value;
 		entry->depth = cur_depth;
 		entry->action = best_action;
 	}
 
-	return value;
+	return best_value;
 }