From: Fabian Fichter <ianfab@users.noreply.github.com>
Date: Sat, 14 Nov 2020 18:11:18 +0000 (+0100)
Subject: Skip NNUE rotation for racing kings
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=6bb7234632f6540478ca718fae1e522cdbe95777;p=fairystockfish.git

Skip NNUE rotation for racing kings
---

diff --git a/src/nnue/features/half_kp.cpp b/src/nnue/features/half_kp.cpp
index 6a09192..9dfa703 100644
--- a/src/nnue/features/half_kp.cpp
+++ b/src/nnue/features/half_kp.cpp
@@ -24,20 +24,20 @@
 namespace Eval::NNUE::Features {
 
   // Orient a square according to perspective (rotates by 180 for black)
-  inline Square orient(Color perspective, Square s) {
+  inline Square orient(const Position& pos, Color perspective, Square s) {
 #ifdef LARGEBOARDS
-    return Square(int(rank_of(s) * 8 + file_of(s)) ^ (bool(perspective) * 63));
+    return Square(int(rank_of(s) * 8 + file_of(s)) ^ (!(pos.capture_the_flag(BLACK) & Rank8BB) * bool(perspective) * 63));
 #else
-    return Square(int(s) ^ (bool(perspective) * 63));
+    return Square(int(s) ^ (!(pos.capture_the_flag(BLACK) & Rank8BB) * bool(perspective) * 63));
 #endif
   }
 
   // Find the index of the feature quantity from the king position and PieceSquare
   template <Side AssociatedKing>
   inline IndexType HalfKP<AssociatedKing>::MakeIndex(
-      Color perspective, Square s, Piece pc, Square ksq) {
+      const Position& pos, Color perspective, Square s, Piece pc, Square ksq) {
 
-    return IndexType(orient(perspective, s) + kpp_board_index[pc][perspective] + PS_END * ksq);
+    return IndexType(orient(pos, perspective, s) + kpp_board_index[pc][perspective] + PS_END * ksq);
   }
 
   // Get a list of indices for active features
@@ -45,11 +45,11 @@ namespace Eval::NNUE::Features {
   void HalfKP<AssociatedKing>::AppendActiveIndices(
       const Position& pos, Color perspective, IndexList* active) {
 
-    Square ksq = orient(perspective, pos.square<KING>(perspective));
+    Square ksq = orient(pos, perspective, pos.square<KING>(perspective));
     Bitboard bb = pos.pieces() & ~pos.pieces(KING);
     while (bb) {
       Square s = pop_lsb(&bb);
-      active->push_back(MakeIndex(perspective, s, pos.piece_on(s), ksq));
+      active->push_back(MakeIndex(pos, perspective, s, pos.piece_on(s), ksq));
     }
   }
 
@@ -59,14 +59,14 @@ namespace Eval::NNUE::Features {
       const Position& pos, const DirtyPiece& dp, Color perspective,
       IndexList* removed, IndexList* added) {
 
-    Square ksq = orient(perspective, pos.square<KING>(perspective));
+    Square ksq = orient(pos, perspective, pos.square<KING>(perspective));
     for (int i = 0; i < dp.dirty_num; ++i) {
       Piece pc = dp.piece[i];
       if (type_of(pc) == KING) continue;
       if (dp.from[i] != SQ_NONE)
-        removed->push_back(MakeIndex(perspective, dp.from[i], pc, ksq));
+        removed->push_back(MakeIndex(pos, perspective, dp.from[i], pc, ksq));
       if (dp.to[i] != SQ_NONE)
-        added->push_back(MakeIndex(perspective, dp.to[i], pc, ksq));
+        added->push_back(MakeIndex(pos, perspective, dp.to[i], pc, ksq));
     }
   }
 
diff --git a/src/nnue/features/half_kp.h b/src/nnue/features/half_kp.h
index ff29657..98e797f 100644
--- a/src/nnue/features/half_kp.h
+++ b/src/nnue/features/half_kp.h
@@ -55,7 +55,7 @@ namespace Eval::NNUE::Features {
 
    private:
     // Index of a feature for a given king position and another piece on some square
-    static IndexType MakeIndex(Color perspective, Square s, Piece pc, Square sq_k);
+    static IndexType MakeIndex(const Position& pos, Color perspective, Square s, Piece pc, Square sq_k);
   };
 
 }  // namespace Eval::NNUE::Features