From: Giacomo Lorenzetti <g.lorenz9@protonmail.com>
Date: Tue, 1 Mar 2022 08:34:40 +0000 (+0100)
Subject: Sort captures
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=4ac7d726ec5ba38ba593bca2ab5cb7589785a957

Sort captures

This patch (partially) sort captures in analogy to quiet moves. All
three movepickers are affected, hence `depth` is added as an argument in
probcut's.

Passed STC:
https://tests.stockfishchess.org/tests/view/621a4576da649bba32ef6fd4
LLR: 2.95 (-2.94,2.94) <0.00,2.50>
Total: 103848 W: 27884 L: 27473 D: 48491
Ptnml(0-2): 587, 11691, 26974, 12068, 604

Passed LTC:
https://tests.stockfishchess.org/tests/view/621aaa5bda649bba32ef7c2d
LLR: 2.96 (-2.94,2.94) <0.50,3.00>
Total: 212032 W: 56420 L: 55739 D: 99873
Ptnml(0-2): 198, 21310, 62348, 21933, 227

closes https://github.com/official-stockfish/Stockfish/pull/3952

Bench: 6833580
---

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 694b9222..dc35113f 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -87,8 +87,8 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const ButterflyHist
 
 /// MovePicker constructor for ProbCut: we generate captures with SEE greater
 /// than or equal to the given threshold.
-MovePicker::MovePicker(const Position& p, Move ttm, Value th, const CapturePieceToHistory* cph)
-           : pos(p), captureHistory(cph), ttMove(ttm), threshold(th)
+MovePicker::MovePicker(const Position& p, Move ttm, Value th, Depth d, const CapturePieceToHistory* cph)
+           : pos(p), captureHistory(cph), ttMove(ttm), threshold(th), depth(d)
 {
   assert(!pos.checkers());
 
@@ -169,11 +169,12 @@ top:
       endMoves = generate<CAPTURES>(pos, cur);
 
       score<CAPTURES>();
+      partial_insertion_sort(cur, endMoves, -3000 * depth);
       ++stage;
       goto top;
 
   case GOOD_CAPTURE:
-      if (select<Best>([&](){
+      if (select<Next>([&](){
                        return pos.see_ge(*cur, Value(-69 * cur->value / 1024)) ?
                               // Move losing capture to endBadCaptures to be tried later
                               true : (*endBadCaptures++ = *cur, false); }))
@@ -241,10 +242,10 @@ top:
       return select<Best>([](){ return true; });
 
   case PROBCUT:
-      return select<Best>([&](){ return pos.see_ge(*cur, threshold); });
+      return select<Next>([&](){ return pos.see_ge(*cur, threshold); });
 
   case QCAPTURE:
-      if (select<Best>([&](){ return   depth > DEPTH_QS_RECAPTURES
+      if (select<Next>([&](){ return   depth > DEPTH_QS_RECAPTURES
                                     || to_sq(*cur) == recaptureSquare; }))
           return *(cur - 1);
 
diff --git a/src/movepick.h b/src/movepick.h
index e2cbfcde..9a3c279b 100644
--- a/src/movepick.h
+++ b/src/movepick.h
@@ -126,7 +126,7 @@ public:
                                            const CapturePieceToHistory*,
                                            const PieceToHistory**,
                                            Square);
-  MovePicker(const Position&, Move, Value, const CapturePieceToHistory*);
+  MovePicker(const Position&, Move, Value, Depth, const CapturePieceToHistory*);
   Move next_move(bool skipQuiets = false);
 
 private:
diff --git a/src/search.cpp b/src/search.cpp
index 6785ba4c..a6552daf 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -863,7 +863,7 @@ namespace {
     {
         assert(probCutBeta < VALUE_INFINITE);
 
-        MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory);
+        MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, depth - 3, &captureHistory);
         bool ttPv = ss->ttPv;
         ss->ttPv = false;