From b973e40e45d75c3b3391141d149d4186494d4652 Mon Sep 17 00:00:00 2001
From: FauziAkram <fauzi.dabat@hotmail.com>
Date: Tue, 21 Mar 2023 23:58:25 +0300
Subject: [PATCH] Update Elo estimates for terms in search

Setting the Elo value of some functions which were not set before.
All tests run at 10+0.1 (STC), 25000 games (Same as #4294).
Book used: UHO_XXL_+0.90_+1.19.epd

Values are rounded to the nearest non-negative integer.

Test links:
https://tests.stockfishchess.org/tests/view/6419ab5b65775d3b539f46c6
https://tests.stockfishchess.org/tests/view/6419adb465775d3b539f4730
https://tests.stockfishchess.org/tests/view/6419ae9c65775d3b539f4756
https://tests.stockfishchess.org/tests/view/6419b03f65775d3b539f47a8
https://tests.stockfishchess.org/tests/view/6419b35d65775d3b539f4860
https://tests.stockfishchess.org/tests/view/6419b6b965775d3b539f48e6
https://tests.stockfishchess.org/tests/view/6419cade65775d3b539f4cd5
https://tests.stockfishchess.org/tests/view/6419cbb565775d3b539f4d01
https://tests.stockfishchess.org/tests/view/6419cc6965775d3b539f4d1e

closes https://github.com/official-stockfish/Stockfish/pull/4459

No functional change
---
 src/search.cpp | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/search.cpp b/src/search.cpp
index 7564c109..b2983f66 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -732,7 +732,7 @@ namespace {
     }
     else if (excludedMove)
     {
-        // Providing the hint that this node's accumulator will be used often brings significant Elo gain (13 elo)
+        // Providing the hint that this node's accumulator will be used often brings significant Elo gain (13 Elo)
         Eval::NNUE::hint_common_parent_position(pos);
         eval = ss->staticEval;
         complexity = abs(ss->staticEval - pos.psq_eg_stm());
@@ -1120,15 +1120,15 @@ moves_loop: // When in check, search starts here
               else if (singularBeta >= beta)
                   return singularBeta;
 
-              // If the eval of ttMove is greater than beta, we reduce it (negative extension)
+              // If the eval of ttMove is greater than beta, we reduce it (negative extension) (~7 Elo)
               else if (ttValue >= beta)
                   extension = -2 - !PvNode;
 
-              // If the eval of ttMove is less than value, we reduce it (negative extension)
+              // If the eval of ttMove is less than value, we reduce it (negative extension) (~1 Elo)
               else if (ttValue <= value)
                   extension = -1;
 
-              // If the eval of ttMove is less than alpha, we reduce it (negative extension)
+              // If the eval of ttMove is less than alpha, we reduce it (negative extension) (~1 Elo)
               else if (ttValue <= alpha)
                   extension = -1;
           }
@@ -1182,7 +1182,7 @@ moves_loop: // When in check, search starts here
       if (ttCapture)
           r++;
 
-      // Decrease reduction for PvNodes based on depth
+      // Decrease reduction for PvNodes based on depth (~2 Elo)
       if (PvNode)
           r -= 1 + 12 / (3 + depth);
 
@@ -1195,11 +1195,11 @@ moves_loop: // When in check, search starts here
           && (mp.threatenedPieces & from_sq(move)))
           r--;
 
-      // Increase reduction if next ply has a lot of fail high
+      // Increase reduction if next ply has a lot of fail high (~5 Elo)
       if ((ss+1)->cutoffCnt > 3)
           r++;
 
-      // Decrease reduction if move is a killer and we have a good history
+      // Decrease reduction if move is a killer and we have a good history (~1 Elo)
       if (move == ss->killers[0]
           && (*contHist[0])[movedPiece][to_sq(move)] >= 3722)
           r--;
@@ -1210,7 +1210,7 @@ moves_loop: // When in check, search starts here
                      + (*contHist[3])[movedPiece][to_sq(move)]
                      - 4182;
 
-      // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
+      // Decrease/increase reduction for moves with a good/bad history (~25 Elo)
       r -= ss->statScore / (11791 + 3992 * (depth > 6 && depth < 19));
 
       // Step 17. Late moves reduction / extension (LMR, ~117 Elo)
@@ -1347,7 +1347,7 @@ moves_loop: // When in check, search starts here
               {
                   alpha = value;
 
-                  // Reduce other moves if we have found at least one score improvement
+                  // Reduce other moves if we have found at least one score improvement (~1 Elo)
                   if (   depth > 1
                       && depth < 6
                       && beta  <  10534
@@ -1413,7 +1413,7 @@ moves_loop: // When in check, search starts here
         bestValue = std::min(bestValue, maxValue);
 
     // If no good move is found and the previous position was ttPv, then the previous
-    // opponent move is probably good and the new position is added to the search tree.
+    // opponent move is probably good and the new position is added to the search tree. (~7 Elo)
     if (bestValue <= alpha)
         ss->ttPv = ss->ttPv || ((ss-1)->ttPv && depth > 3);
 
@@ -1432,7 +1432,7 @@ moves_loop: // When in check, search starts here
 
   // qsearch() is the quiescence search function, which is called by the main search
   // function with zero depth, or recursively with further decreasing depth per call.
-  // (~155 elo)
+  // (~155 Elo)
   template <NodeType nodeType>
   Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) {