Make effort part of RootMove struct

Also includes several small cleanups.

Passed STC:
https://tests.stockfishchess.org/tests/view/65f15cfe0ec64f0526c473a0
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 71136 W: 18456 L: 18273 D: 34407
Ptnml(0-2): 311, 8014, 18708, 8251, 284

closes https://github.com/official-stockfish/Stockfish/pull/5114

No functional change

src/search.cpp

@@ -214,7 +214,7 @@ void Search::Worker::start_searching() {
 // consumed, the user stops the search, or the maximum search depth is reached.
 void Search::Worker::iterative_deepening() {
 
-    SearchManager* mainThread = (thread_idx == 0 ? main_manager() : nullptr);
+    SearchManager* mainThread = (is_mainthread() ? main_manager() : nullptr);
 
     Move pv[MAX_PLY + 1];
 
@@ -426,9 +426,7 @@ void Search::Worker::iterative_deepening() {
         // Do we have time for the next iteration? Can we stop searching now?
         if (limits.use_time_management() && !threads.stop && !mainThread->stopOnPonderhit)
         {
-            auto bestmove    = rootMoves[0].pv[0];
+            int nodesEffort = rootMoves[0].effort * 100 / std::max(size_t(1), size_t(nodes));
-            int  nodesEffort = effort[bestmove.from_sq()][bestmove.to_sq()] * 100
-                            / std::max(size_t(1), size_t(nodes));
 
             double fallingEval = (1067 + 223 * (mainThread->bestPreviousAverageScore - bestValue)
                                   + 97 * (mainThread->iterValue[iterIdx] - bestValue))
@@ -450,9 +448,7 @@ void Search::Worker::iterative_deepening() {
             if (completedDepth >= 10 && nodesEffort >= 97
                 && mainThread->tm.elapsed(threads.nodes_searched()) > totalTime * 0.739
                 && !mainThread->ponder)
-            {
                 threads.stop = true;
-            }
 
             // Stop the search if we have exceeded the totalTime
             if (mainThread->tm.elapsed(threads.nodes_searched()) > totalTime)
@@ -1199,9 +1195,6 @@ moves_loop:  // When in check, search starts here
         // Step 19. Undo move
         pos.undo_move(move);
 
-        if (rootNode)
-            effort[move.from_sq()][move.to_sq()] += nodes - nodeCount;
-
         assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
 
         // Step 20. Check for a new best move
@@ -1216,6 +1209,8 @@ moves_loop:  // When in check, search starts here
             RootMove& rm =
               *std::find(thisThread->rootMoves.begin(), thisThread->rootMoves.end(), move);
 
+            rm.effort += nodes - nodeCount;
+
             rm.averageScore =
               rm.averageScore != -VALUE_INFINITE ? (2 * value + rm.averageScore) / 3 : value;
 

src/search.h

@@ -89,6 +89,7 @@ struct RootMove {
         return m.score != score ? m.score < score : m.previousScore < previousScore;
     }
 
+    uint64_t          effort          = 0;
     Value             score           = -VALUE_INFINITE;
     Value             previousScore   = -VALUE_INFINITE;
     Value             averageScore    = -VALUE_INFINITE;
@@ -230,8 +231,6 @@ class Worker {
         return static_cast<SearchManager*>(manager.get());
     }
 
-    std::array<std::array<uint64_t, SQUARE_NB>, SQUARE_NB> effort;
-
     LimitsType limits;
 
     size_t                pvIdx, pvLast;

src/thread.cpp

@@ -19,7 +19,6 @@
 #include "thread.h"
 
 #include <algorithm>
-#include <array>
 #include <cassert>
 #include <deque>
 #include <memory>
@@ -211,7 +210,6 @@ void ThreadPool::start_thinking(const OptionsMap&  options,
         th->worker->rootPos.set(pos.fen(), pos.is_chess960(), &th->worker->rootState);
         th->worker->rootState = setupStates->back();
         th->worker->tbConfig  = tbConfig;
-        th->worker->effort    = {};
     }
 
     main_thread()->start_searching();