STARLIGHT code and interface

[u/mrichter/AliRoot.git] / STARLIGHT / starlight / src / .svn / text-base / randomgenerator.cpp.svn-base

diff --git a/STARLIGHT/starlight/src/.svn/text-base/randomgenerator.cpp.svn-base b/STARLIGHT/starlight/src/.svn/text-base/randomgenerator.cpp.svn-base
new file mode 100644 (file)
index 0000000..1afd682
--- /dev/null
+++ b/STARLIGHT/starlight/src/.svn/text-base/randomgenerator.cpp.svn-base
@@ -0,0 +1,153 @@
+///////////////////////////////////////////////////////////////////////////
+//
+//    Copyright 2010
+//
+//    This file is part of starlight.
+//
+//    starlight 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.
+//
+//    starlight 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.
+//
+//    You should have received a copy of the GNU General Public License
+//    along with starlight. If not, see <http://www.gnu.org/licenses/>.
+//
+///////////////////////////////////////////////////////////////////////////
+//
+// File and Version Information:
+// $Rev::                             $: revision of last commit
+// $Author::                          $: author of last commit
+// $Date::                            $: date of last commit
+//
+// Description:
+//
+//
+//
+///////////////////////////////////////////////////////////////////////////
+
+
+#include <iostream>
+#include <fstream>
+#include <cmath>
+
+#include "randomgenerator.h"
+
+
+using namespace std;
+
+
+//USED IN ROOT under TRANDOM3
+// Random number generator class based on
+//   M. Matsumoto and T. Nishimura,
+//   Mersenne Twistor: A 623-diminsionally equidistributed
+//   uniform pseudorandom number generator
+//   ACM Transactions on Modeling and Computer Simulation,
+//   Vol. 8, No. 1, January 1998, pp 3--30.
+//
+// For more information see the Mersenne Twistor homepage
+//   http://www.math.keio.ac.jp/~matumoto/emt.html
+//
+// Advantage: large period 2**19937-1
+//            relativly fast
+//              (only two times slower than TRandom, but
+//               two times faster than TRandom2)
+// Drawback:  a relative large internal state of 624 integers
+//
+//
+// Aug.99 ROOT implementation based on CLHEP by P.Malzacher
+//
+// the original code contains the following copyright notice:
+/* This library is free software; you can redistribute it and/or   */
+/* modify it under the terms of the GNU Library General Public     */
+/* License as published by the Free Software Foundation; either    */
+/* version 2 of the License, or (at your option) any later         */
+/* version.                                                        */
+/* This library 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 Library General Public License for more details.    */
+/* You should have received a copy of the GNU Library General      */
+/* Public License along with this library; if not, write to the    */
+/* Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA   */
+/* 02111-1307  USA                                                 */
+/* Copyright (C) 1997 Makoto Matsumoto and Takuji Nishimura.       */
+/* When you use this, send an email to: matumoto@math.keio.ac.jp   */
+/* with an appropriate reference to your work.                     */
+/////////////////////////////////////////////////////////////////////
+
+
+void randomGenerator::SetSeed(unsigned int seed)
+{
+//  Set the random generator sequence
+// if seed is 0 (default value) a TUUID is generated and used to fill
+// the first 8 integers of the seed array.
+// In this case the seed is guaranteed to be unique in space and time.
+// Use upgraded seeding procedure to fix a known problem when seeding with values
+// with many zero in the bit pattern (like 2**28).
+// see http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/emt19937ar.html
+
+  Lockguard<MutexPosix> guard(&_mutex);
+  
+  _count624 = 624;
+  int i,j;
+  
+  _Mt[0] = seed;
+  j = 1;
+  // use multipliers from  Knuth's "Art of Computer Programming" Vol. 2, 3rd Ed. p.106
+  for(i=j; i<624; i++) {
+    _Mt[i] = (1812433253 * ( _Mt[i-1]  ^ ( _Mt[i-1] >> 30)) + i);
+  }
+}
+
+
+double randomGenerator::Rndom(int)
+{
+
+//  Machine independent random number generator.
+//  Produces uniformly-distributed floating points in ]0,1]
+//  Method: Mersenne Twistor
+
+   Lockguard<MutexPosix> guard(&_mutex);
+   
+   unsigned int y;
+
+   const int  kM = 397;
+   const int  kN = 624;
+   const unsigned int kTemperingMaskB =  0x9d2c5680;
+   const unsigned int kTemperingMaskC =  0xefc60000;
+   const unsigned int kUpperMask =       0x80000000;
+   const unsigned int kLowerMask =       0x7fffffff;
+   const unsigned int kMatrixA =         0x9908b0df;
+
+   if (_count624 >= kN) {
+      register int i;
+
+      for (i=0; i < kN-kM; i++) {
+         y = (_Mt[i] & kUpperMask) | (_Mt[i+1] & kLowerMask);
+         _Mt[i] = _Mt[i+kM] ^ (y >> 1) ^ ((y & 0x1) ? kMatrixA : 0x0);
+      }
+
+      for (   ; i < kN-1    ; i++) {
+         y = (_Mt[i] & kUpperMask) | (_Mt[i+1] & kLowerMask);
+         _Mt[i] = _Mt[i+kM-kN] ^ (y >> 1) ^ ((y & 0x1) ? kMatrixA : 0x0);
+      }
+
+      y = (_Mt[kN-1] & kUpperMask) | (_Mt[0] & kLowerMask);
+      _Mt[kN-1] = _Mt[kM-1] ^ (y >> 1) ^ ((y & 0x1) ? kMatrixA : 0x0);
+      _count624 = 0;
+   }
+
+   y = _Mt[_count624++];
+   y ^=  (y >> 11);
+   y ^= ((y << 7 ) & kTemperingMaskB );
+   y ^= ((y << 15) & kTemperingMaskC );
+   y ^=  (y >> 18);
+
+   if (y) return ( (double) y * 2.3283064365386963e-10); // * Power(2,-32)
+   return Rndom();
+}