feat: add aspiration window

1 files changed, 7 insertions, 2 deletions

diff --git a/src/main.c b/src/main.c
index a6ef917..1c5664a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -585,8 +585,8 @@ int order_moves(Move* moves, int moves_count, int* board, long hash, Transpositi
  */
 Move minimax_search(int* board, int color, int depth, int alpha, int beta, int* metrics, long hash, Transposition* transposition_table, long* zobrist_seed, clock_t deadline) {
   int is_maximizer = (color == 0);
-
   Move best_move = { -100, -100, 0 };
+
   best_move.value = is_maximizer ? -100 * INFINITY / (depth + 1) : 100 * INFINITY / (depth + 1);
 
   // You only have available moves if your king hasn't been taken
@@ -638,13 +638,15 @@ Move iterative_deepening(int* board, int color, long hash, Transposition* transp
   int depth = 0;
   clock_t start = clock();
   clock_t deadline = start + MOVE_TIME * CLOCKS_PER_SEC;
+  int alpha = -INFINITY;
+  int beta = +INFINITY;
 
   while (depth <= MAX_DEPTH) {
     best_move = move;
     printf("Searching with depth %i... [%.2f seconds left]\n", depth, (double)(deadline - clock()) / CLOCKS_PER_SEC);
 
     int metrics = 0;
-    move = minimax_search(board, color, depth, -INFINITY, +INFINITY, &metrics, hash, transposition_table, zobrist_seed, deadline);
+    move = minimax_search(board, color, depth, alpha, beta, &metrics, hash, transposition_table, zobrist_seed, deadline);
 
     if (clock() > deadline) {
       printf("Out of time! Falling back to result with depth %i\n", depth - 1);
@@ -656,6 +658,9 @@ Move iterative_deepening(int* board, int color, long hash, Transposition* transp
     index_to_notation(move.destination, move_in_notation + 2);
     printf("Done (%s with evaluation %.2f)    [%i positions analyzed]\n", move_in_notation, (double)move.value / 10, metrics);
 
+    alpha = move.value - 3;
+    beta = move.value + 3;
+
     depth++;
   }