X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Frkiss.h;h=47a3d4cbd6bee9affaab2a8e9508f6a8923328c7;hp=5c01a0e56403da996e95a2997080698d2d3d764c;hb=b50eb6bea866a297cd59eb92b7d552480544ff8d;hpb=c2511243b40964e5ed5f35447baf5663a72da72a

diff --git a/src/rkiss.h b/src/rkiss.h
index 5c01a0e5..47a3d4cb 100644
--- a/src/rkiss.h
+++ b/src/rkiss.h
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -20,19 +20,6 @@
   available under the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
-
- ** George Marsaglia invented the RNG-Kiss-family in the early 90's.
- ** This is a specific version that Heinz van Saanen derived and
- ** tested from some public domain code by Bob Jenkins:
- **
- ** Quite platform independent
- ** Passes ALL dieharder tests! Here *nix sys-rand() e.g. fails miserably:-)
- ** ~12 times faster than my *nix sys-rand()
- ** ~4 times faster than SSE2-version of Mersenne twister
- ** Average cycle length: ~2^126
- ** 64 bit seed
- ** Return doubles with a full 53 bit mantissa
- ** Thread safe
 */
 
 #if !defined(RKISS_H_INCLUDED)
@@ -40,6 +27,20 @@
 
 #include "types.h"
 
+/// RKISS is our pseudo random number generator (PRNG) used to compute hash keys.
+/// George Marsaglia invented the RNG-Kiss-family in the early 90's. This is a
+/// specific version that Heinz van Saanen derived from some public domain code
+/// by Bob Jenkins. Following the feature list, as tested by Heinz.
+///
+/// - Quite platform independent
+/// - Passes ALL dieharder tests! Here *nix sys-rand() e.g. fails miserably:-)
+/// - ~12 times faster than my *nix sys-rand()
+/// - ~4 times faster than SSE2-version of Mersenne twister
+/// - Average cycle length: ~2^126
+/// - 64 bit seed
+/// - Return doubles with a full 53 bit mantissa
+/// - Thread safe
+
 class RKISS {
 
   // Keep variables always together
@@ -60,17 +61,15 @@ class RKISS {
     return s.d = e + s.a;
   }
 
-  // Init seed and scramble a few rounds
-  void raninit() {
+public:
+  RKISS(int seed = 73) {
 
     s.a = 0xf1ea5eed;
     s.b = s.c = s.d = 0xd4e12c77;
-    for (int i = 0; i < 73; i++)
+    for (int i = 0; i < seed; i++) // Scramble a few rounds
         rand64();
   }
 
-public:
-  RKISS() { raninit(); }
   template<typename T> T rand() { return T(rand64()); }
 };