Change advanced pawn push threshold

TopoIogist · snicolet · commit f3b296c2e206 · 2021-03-10T12:32:53.000+01:00
A pawn push is now considered to be "advanced" if the relative destination rank is > 6 (previously it was > 5). This affects the search heuristic. Also remove an assert concerning en passant moves in qsearch(). STC: LLR: 2.97 (-2.94,2.94) {-0.25,1.25} Total: 46744 W: 4224 L: 4040 D: 38480 Ptnml(0-2): 165, 3206, 16451, 3380, 170 https://tests.stockfishchess.org/tests/view/604746082433018de7a3872e LTC: LLR: 2.94 (-2.94,2.94) {0.25,1.25} Total: 107840 W: 4198 L: 3892 D: 99750 Ptnml(0-2): 58, 3472, 46557, 3772, 61 https://tests.stockfishchess.org/tests/view/60475eae2433018de7a38737 Closes #3389 Bench: 4796780
diff --git a/AUTHORS b/AUTHORS
@@ -168,6 +168,7 @@ Sergio Vieri (sergiovieri)
 sf-x
 Shane Booth (shane31)
 Shawn Varghese (xXH4CKST3RXx)
+Siad Daboul (Topologist)
 Stefan Geschwentner (locutus2)
 Stefano Cardanobile (Stefano80)
 Steinar Gunderson (sesse)
diff --git a/src/position.h b/src/position.h
@@ -312,7 +312,7 @@ inline bool Position::pawn_passed(Color c, Square s) const {
 
 inline bool Position::advanced_pawn_push(Move m) const {
   return   type_of(moved_piece(m)) == PAWN
-        && relative_rank(sideToMove, to_sq(m)) > RANK_5;
+        && relative_rank(sideToMove, to_sq(m)) > RANK_6;
 }
 
 inline int Position::pawns_on_same_color_squares(Color c, Square s) const {
diff --git a/src/search.cpp b/src/search.cpp
@@ -1575,15 +1575,13 @@ namespace {
 
       moveCount++;
 
-      // Futility pruning
+      // Futility pruning and moveCount pruning
       if (    bestValue > VALUE_TB_LOSS_IN_MAX_PLY
           && !givesCheck
           &&  futilityBase > -VALUE_KNOWN_WIN
           && !pos.advanced_pawn_push(move))
       {
-          assert(type_of(move) != EN_PASSANT); // Due to !pos.advanced_pawn_push
 
-          // moveCount pruning
           if (moveCount > 2)
               continue;
 

Original file line number	Diff line number	Diff line change
`@@ -312,7 +312,7 @@ inline bool Position::pawn_passed(Color c, Square s) const {`
`312`	`312`
`313`	`313`	`inline bool Position::advanced_pawn_push(Move m) const {`
`314`	`314`	`return type_of(moved_piece(m)) == PAWN`
`315`		`- && relative_rank(sideToMove, to_sq(m)) > RANK_5;`
	`315`	`+ && relative_rank(sideToMove, to_sq(m)) > RANK_6;`
`316`	`316`	`}`
`317`	`317`
`318`	`318`	`inline int Position::pawns_on_same_color_squares(Color c, Square s) const {`