From 15e190e9428b21fbfe29ce020c456077dc5fdd04 Mon Sep 17 00:00:00 2001
From: pb00067 <pb00067@PHXL0356.wp.lan>
Date: Sat, 6 Jun 2020 12:56:38 +0200
Subject: [PATCH] Use lowply-history also on low depths

STC:
https://tests.stockfishchess.org/tests/view/5ed75078f29b40b0fc95a8b9
LLR: 2.93 (-2.94,2.94) {-0.50,1.50}
Total: 73928 W: 14301 L: 14005 D: 45622
Ptnml(0-2): 1243, 8572, 17096, 8752, 1301

LTC:
https://tests.stockfishchess.org/tests/view/5ed895e0f29b40b0fc95a976
LLR: 2.93 (-2.94,2.94) {0.25,1.75}
Total: 154848 W: 19684 L: 19074 D: 116090
Ptnml(0-2): 1048, 14108, 46627, 14468, 1173

closes https://github.com/official-stockfish/Stockfish/pull/2718

bench: 4582693
---
 src/movepick.cpp | 2 +-
 src/search.cpp   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/movepick.cpp b/src/movepick.cpp
index e26f42ef..78102c52 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -110,7 +110,7 @@ void MovePicker::score() {
                    + 2 * (*continuationHistory[1])[pos.moved_piece(m)][to_sq(m)]
                    + 2 * (*continuationHistory[3])[pos.moved_piece(m)][to_sq(m)]
                    +     (*continuationHistory[5])[pos.moved_piece(m)][to_sq(m)]
-                   + (ply < MAX_LPH ?  4 * (*lowPlyHistory)[ply][from_to(m)] : 0);
+                   + (ply < MAX_LPH ? std::min(4, depth / 3) * (*lowPlyHistory)[ply][from_to(m)] : 0);
 
       else // Type == EVASIONS
       {
diff --git a/src/search.cpp b/src/search.cpp
index 35110538..efa7b9c5 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -971,7 +971,7 @@ moves_loop: // When in check, search starts from here
                                       contHist,
                                       countermove,
                                       ss->killers,
-                                      depth > 12 ? ss->ply : MAX_PLY);
+                                      ss->ply);
 
     value = bestValue;
     singularQuietLMR = moveCountPruning = false;
-- 
2.39.2