Introduce variant piece values

For future improvements. No functional change.
fairy-stockfish · Jan 4, 2021 · f4864ec · f4864ec
1 parent 34a0823
commit f4864ec
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Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/src/psqt.cpp b/src/psqt.cpp
@@ -25,6 +25,9 @@
 #include "variant.h"
 #include "misc.h"
 
+Value EvalPieceValue[PHASE_NB][PIECE_NB];
+Value CapturePieceValue[PHASE_NB][PIECE_NB];
+
 namespace PSQT {
 
 #define S(mg, eg) make_score(mg, eg)
@@ -157,8 +160,8 @@ void init(const Variant* v) {
 
       // For drop variants, halve the piece values
       if (v->capturesToHand)
-          score = make_score(mg_value(score) * 3500 / (7000 + mg_value(score)),
-                             eg_value(score) * 3500 / (7000 + eg_value(score)));
+          score = make_score(mg_value(score) * 7000 / (7000 + mg_value(score)),
+                             eg_value(score) * 7000 / (7000 + eg_value(score)));
       else if (!v->checking)
           score = make_score(mg_value(score) * 2000 / (3500 + mg_value(score)),
                              eg_value(score) * 2200 / (3500 + eg_value(score)));
@@ -176,10 +179,19 @@ void init(const Variant* v) {
               score += make_score(std::max(QueenValueMg - PieceValue[MG][pt], VALUE_ZERO) / 20,
                                   std::max(QueenValueEg - PieceValue[EG][pt], VALUE_ZERO) / 20);
 
+      CapturePieceValue[MG][pc] = CapturePieceValue[MG][~pc] = mg_value(score);
+      CapturePieceValue[EG][pc] = CapturePieceValue[EG][~pc] = eg_value(score);
+
       // For antichess variants, use negative piece values
       if (v->extinctionValue == VALUE_MATE)
           score = -make_score(mg_value(score) / 8, eg_value(score) / 8 / (1 + !pi->sliderCapture.size()));
 
+      if (v->capturesToHand)
+          score = score / 2;
+
+      EvalPieceValue[MG][pc] = EvalPieceValue[MG][~pc] = mg_value(score);
+      EvalPieceValue[EG][pc] = EvalPieceValue[EG][~pc] = eg_value(score);
+
       // Determine pawn rank
       std::istringstream ss(v->startFen);
       unsigned char token;

diff --git a/src/types.h b/src/types.h
@@ -470,6 +470,9 @@ constexpr Value PieceValue[PHASE_NB][PIECE_NB] = {
 static_assert(   PieceValue[MG][PIECE_TYPE_NB + 1] == PawnValueMg
               && PieceValue[EG][PIECE_TYPE_NB + 1] == PawnValueEg, "PieceValue array broken");
 
+extern Value EvalPieceValue[PHASE_NB][PIECE_NB]; // variant piece values for evaluation
+extern Value CapturePieceValue[PHASE_NB][PIECE_NB]; // variant piece values for captures/search
+
 typedef int Depth;
 
 enum : int {