Make rkiss seed deterministic

[stockfish] / src / book.cpp

diff --git a/src/book.cpp b/src/book.cpp
index 20861988b24c906b1ba04c5788b6dc9014a553ca..2aca81cfd0b81971c2c7086de1f331e983464842 100644 (file)
--- a/src/book.cpp
+++ b/src/book.cpp
@@ -32,7 +32,6 @@
 #include <cassert>
 
 #include "book.h"
-#include "mersenne.h"
 #include "movegen.h"
 
 using namespace std;
@@ -343,6 +342,13 @@ namespace {
 //// Functions
 ////
 
+// C'tor. Make random number generation less deterministic, for book moves
+Book::Book() {
+
+  for (int i = abs(get_system_time() % 10000); i > 0; i--)
+      RKiss.rand<unsigned>();
+}
+
 
 /// Destructor. Be sure file is closed before we leave.
 
@@ -366,7 +372,7 @@ void Book::open(const string& fName) {
 
   // Get the book size in number of entries
   seekg(0, ios::end);
-  bookSize = tellg() / EntrySize;
+  bookSize = long(tellg()) / EntrySize;
   seekg(0, ios::beg);
 
   if (!good())
@@ -399,14 +405,15 @@ const string Book::file_name() { // Not const to compile on HP-UX 11.X
 /// Book::get_move() gets a book move for a given position. Returns
 /// MOVE_NONE if no book move is found.
 
-Move Book::get_move(const Position& pos) {
+Move Book::get_move(const Position& pos, bool findBestMove) {
 
   if (!is_open() || bookSize == 0)
       return MOVE_NONE;
 
-  int bookMove = 0, scoresSum = 0;
-  uint64_t key = book_key(pos);
   BookEntry entry;
+  int bookMove = MOVE_NONE;
+  unsigned scoresSum = 0, bestScore = 0;
+  uint64_t key = book_key(pos);
 
   // Choose a book move among the possible moves for the given position
   for (int idx = find_key(key); idx < bookSize; idx++)
@@ -415,21 +422,30 @@ Move Book::get_move(const Position& pos) {
       if (entry.key != key)
           break;
 
-      int score = entry.count;
+      unsigned score = entry.count;
 
-      assert(score > 0);
+      // If findBestMove is true choose highest rated book move
+      if (findBestMove)
+      {
+          if (score > bestScore)
+          {
+              bestScore = score;
+              bookMove = entry.move;
+          }
+          continue;
+      }
 
       // Choose book move according to its score. If a move has a very
       // high score it has more probability to be choosen then a one with
       // lower score. Note that first entry is always chosen.
       scoresSum += score;
-      if (int(genrand_int32() % scoresSum) < score)
+      if (RKiss.rand<unsigned>() % scoresSum < score)
           bookMove = entry.move;
   }
   if (!bookMove)
       return MOVE_NONE;
 
-  MoveStack mlist[256];
+  MoveStack mlist[MOVES_MAX];
   MoveStack* last = generate_moves(pos, mlist);
   for (MoveStack* cur = mlist; cur != last; cur++)
       if ((int(cur->move) & 07777) == bookMove)
@@ -503,7 +519,7 @@ uint64_t Book::read_integer(int size) {
   read(buf, size);
 
   // Numbers are stored on disk as a binary byte stream
-  uint64_t n = 0ULL;
+  uint64_t n = 0;
   for (int i = 0; i < size; i++)
       n = (n << 8) + (unsigned char)buf[i];
 
@@ -519,7 +535,7 @@ namespace {
 
   uint64_t book_key(const Position& pos) {
 
-    uint64_t result = 0ULL;
+    uint64_t result = 0;
 
     for (Color c = WHITE; c <= BLACK; c++)
     {
@@ -554,7 +570,7 @@ namespace {
 
   uint64_t book_castle_key(const Position& pos) {
 
-    uint64_t result = 0ULL;
+    uint64_t result = 0;
 
     if (pos.can_castle_kingside(WHITE))
         result ^= Random64[RandomCastle+0];
@@ -573,11 +589,11 @@ namespace {
 
 
   uint64_t book_ep_key(const Position& pos) {
-    return (pos.ep_square() == SQ_NONE ? 0ULL : Random64[RandomEnPassant + square_file(pos.ep_square())]);
+    return pos.ep_square() == SQ_NONE ? 0 : Random64[RandomEnPassant + square_file(pos.ep_square())];
   }
 
 
   uint64_t book_color_key(const Position& pos) {
-    return (pos.side_to_move() == WHITE ? Random64[RandomTurn] : 0ULL);
+    return pos.side_to_move() == WHITE ? Random64[RandomTurn] : 0;
   }
 }