From 37271bdd778b7b6bfe924f6793d466a73754d31c Mon Sep 17 00:00:00 2001
From: Bruno Raoult <braoult@gmail.com>
Date: Fri, 12 Nov 2021 11:00:11 +0100
Subject: [PATCH] eval: basic mobility

---
 src/eval.c | 53 ++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 36 insertions(+), 17 deletions(-)

diff --git a/src/eval.c b/src/eval.c
index d867854..93bb65e 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -19,39 +19,57 @@
 
 eval_t eval(pos_t *pos)
 {
-    eval_t eval[2] = {0}, res = 0;
+    eval_t material[2] = {0};
+    eval_t control[2] = {0};
+    eval_t res = 0;
     struct list_head *p_cur, *p_tmp, *list;
     piece_list_t *piece;
 
     /* 1) pieces value
      */
-    for (int color=WHITE; color <=BLACK; ++color) {
+    for (int color=0; color <2; ++color) {
         list = &pos->pieces[color];
         list_for_each_safe(p_cur, p_tmp, list) {
             piece = list_entry(p_cur, piece_list_t, list);
-            eval[color] += piece->value;
+            if (PIECE(piece->piece) != KING)
+                material[color] += piece->value;
         }
     }
 
-    res += eval[WHITE] - eval[BLACK];
+    res = material[WHITE] - material[BLACK];
 #   ifdef DEBUG_EVAL
-    log_f(2, "pieces: W:%lu B:%lu diff=%lu eval=\n", eval[WHITE], eval[BLACK],
-          res);
+    log_f(2, "material: W:%ld B:%ld eval=%ld (%.3f pawns)\n",
+          material[WHITE], material[BLACK],
+          material[WHITE] - material[BLACK], (float)res/100);
 #   endif
 
-    /* 2) square control
+    /* 2) square control: 10 square controls diff = 1 pawn
      */
-    eval[WHITE] = popcount64(pos->controlled[WHITE]);
-    eval[BLACK] = popcount64(pos->controlled[BLACK]);
-    res += eval[WHITE] - eval[BLACK];
+    control[WHITE] = popcount64(pos->controlled[WHITE]);
+    control[BLACK] = popcount64(pos->controlled[BLACK]);
+    res = control[WHITE] - control[BLACK];
 #   ifdef DEBUG_EVAL
-    log_f(2, "square control: W:%lu B:%lu eval=%lu\n", eval[WHITE], eval[BLACK],
-          res);
+    log_f(2, "square control: W:%ld B:%ld eval=%ld (%.3f pawns)\n",
+          control[WHITE], control[BLACK],
+          res, (float)res/10);
 #   endif
 
-    /* 3) mobility
+    /* 3) mobility: 5 mobility diff = 1 pawn
      */
+    res = pos->mobility[WHITE] - pos->mobility[BLACK];
+#   ifdef DEBUG_EVAL
+    log_f(2, "mobility: W:%ld B:%ld eval=%ld (%.3f pawns)\n",
+          pos->mobility[WHITE], pos->mobility[BLACK],
+          res, (float)res/5);
+#   endif
 
+    res = material[WHITE] - material[BLACK] +
+        (control[WHITE] - control[BLACK]) * 10 +
+        (pos->mobility[WHITE] - pos->mobility[BLACK]) * 20;
+#   ifdef DEBUG_EVAL
+    log_f(2, "eval: %ld (%.3f pawns)\n",
+          res, (float)res/100);
+#   endif
 
     return res;
 }
@@ -63,6 +81,7 @@ eval_t eval(pos_t *pos)
 int main(int ac, char**av)
 {
     pos_t *pos;
+    eval_t res;
 
     debug_init(2);
     piece_pool_init();
@@ -75,11 +94,11 @@ int main(int ac, char**av)
         fen2pos(pos, av[1]);
     }
 
-    moves_gen(pos, WHITE);
-    moves_gen(pos, BLACK);
+    moves_gen(pos, OPPONENT(pos->turn), false);
+    moves_gen(pos, pos->turn, true);
     pos_print(pos);
     pos_pieces_print(pos);
-
-    printf("eval=%lu\n", eval(pos));
+    res = eval(pos);
+    printf("eval=%ld (%.3f pawns)\n", res, (float)res/100);
 }
 #endif