X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=inline;f=src%2Frkiss.h;h=f3468db4e0f056edede0914c5a9d7cde72ea0bba;hb=a67c22611aea4b643e8278fa6007da316bd06b13;hp=6e94dc27fa723fc8426216df2fbf0bf3cf2e452c;hpb=f5e28ef5127ff29310f9c2e8e321eb24214f2439;p=stockfish
diff --git a/src/rkiss.h b/src/rkiss.h
index 6e94dc27..f3468db4 100644
--- a/src/rkiss.h
+++ b/src/rkiss.h
@@ -1,23 +1,14 @@
-/** *********************************************************************** **
- ** A small "keep it simple and stupid" RNG with some fancy merits:
- **
- ** 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 save
- **
- ** (c) Heinz van Saanen
-
- This file is free software: you can redistribute it and/or modify
+/*
+ Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+ Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+ Copyright (C) 2008-2014 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
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
- This file is distributed in the hope that it will be useful,
+ Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
@@ -25,53 +16,66 @@
You should have received a copy of the GNU General Public License
along with this program. If not, see .
- ** *********************************************************************** **/
-
-#ifndef _RKISS_H_
-#define _RKISS_H_
+ This file is based on original code by Heinz van Saanen and is
+ 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.
+*/
+
+#ifndef RKISS_H_INCLUDED
+#define RKISS_H_INCLUDED
+
+#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
-/** Includes **/
-#include // srand(), rand()
-#include // time()
-#include "types.h" // (u)int8_t .. (u)int64_t
+class RKISS {
+ uint64_t a, b, c, d;
-/** Random class **/
-class RKISS {
+ uint64_t rotate_L(uint64_t x, unsigned k) const {
+ return (x << k) | (x >> (64 - k));
+ }
-private:
- // Keep variables always together
- struct S { uint64_t a; uint64_t b; uint64_t c; uint64_t d; } s;
+ uint64_t rand64() {
- // Init seed and scramble a few rounds
- void raninit ( uint64_t seed ) {
- s.a = 0xf1ea5eed; s.b = s.c = s.d = seed;
- for ( uint64_t i=0; i<8; i++ ) rand64();
- }
+ const uint64_t e = a - rotate_L(b, 7);
+ a = b ^ rotate_L(c, 13);
+ b = c + rotate_L(d, 37);
+ c = d + e;
+ return d = e + a;
+ }
public:
- // Instance seed random or implicite
- RKISS() { ::srand ( (uint32_t)time(NULL) ); raninit ( (uint64_t)::rand() ); }
- // RKISS( uint64_t s ) { raninit ( s ); }
-
- // (Re)init seed
- // void init ( uint64_t seed ) { raninit ( seed ); }
-
- // Return 32 bit unsigned integer in between [0,2^32-1]
- uint32_t rand32 () { return (uint32_t) rand64 (); }
-
- // Return 64 bit unsigned integer in between [0,2^64-1]
- uint64_t rand64 () {
- const uint64_t e = s.a - ((s.b<<7) | (s.b>>57));
- s.a = s.b ^ ((s.c<<13) | (s.c>>51));
- s.b = s.c + ((s.d<<37) | (s.d>>27));
- s.c = s.d + e;
- return s.d = e + s.a;
- }
-
- // Return double in between [0,1). Keep full 53 bit mantissa
- // double frand () { return (int64_t)(rand64()>>11) * (1.0/(67108864.0*134217728.0)); }
+ RKISS(int seed = 73) {
+
+ a = 0xF1EA5EED, b = c = d = 0xD4E12C77;
+
+ for (int i = 0; i < seed; ++i) // Scramble a few rounds
+ rand64();
+ }
+
+ template T rand() { return T(rand64()); }
+
+ /// Special generator used to fast init magic numbers. Here the
+ /// trick is to rotate the randoms of a given quantity 's' known
+ /// to be optimal to quickly find a good magic candidate.
+ template T magic_rand(int s) {
+ return rotate_L(rotate_L(rand(), (s >> 0) & 0x3F) & rand()
+ , (s >> 6) & 0x3F) & rand();
+ }
};
-// _RKISS_H_
-#endif
+#endif // #ifndef RKISS_H_INCLUDED