CLHEP/Random/DualRand.h
// $Id: DualRand.h,v 1.5 2000/04/17 22:59:34 mf Exp $
// -*- C++ -*-
//
// -----------------------------------------------------------------------
// Hep Random
// --- DualRand ---
// class header file
// -----------------------------------------------------------------------
//
// Canopy random number generator DualRand
// Re-written as C++ routine for 32-bit ints MF 1/26/98
//
// Exclusive or of a feedback shift register and integer congruence
// random number generator. The feedback shift register uses offsets
// 127 and 97. The integer congruence generator uses a different
// multiplier for each stream. The multipliers are chosen to give
// full period and maximum "potency" for modulo 2^32. The period of
// the combined random number generator is 2^159 - 2^32, and the
// sequences are different for each stream (not just started in a
// different place).
//
// =======================================================================
// Canopy random number generator DualRand.
// Doug Toussaint 5/25/88
// Optimized by GMH 7/26/88
// Optimized by GMH 7/26/88
// Repaired by GMH 12/1/88 to update modular congruence state
// Put into ranlib by GMH 6/23/89
// Re-written as C++ routine for 32-bit ints MF 1/26/98
// Re-written for CLHEP package KLS 6/04/98
// Removed pow() from flat method for speed KLS 7/21/98
// Ken Smith - Added conversion operators: 6th Aug 1998
// =======================================================================
#ifndef DualRand_h
#define DualRand_h
#include "CLHEP/Random/RandomEngine.h"
class DualRand: public HepRandomEngine {
public:
DualRand();
DualRand(long seed);
DualRand(HepStd::istream & is);
DualRand(HepInt rowIndex, HepInt colIndex);
virtual ~DualRand();
DualRand(const DualRand & p);
DualRand & operator=(const DualRand & p);
HepDouble flat();
// Returns a pseudo random number between 0 and 1
// (excluding the end points)
void flatArray(const HepInt size, HepDouble * vect);
// Fills an array "vect" of specified size with flat random values.
void setSeed(long seed, HepInt);
// Sets the state of the algorithm according to seed.
void setSeeds(const long * seeds, HepInt);
// Sets the state of the algorithm according to the zero-terminated
// array of seeds.
void saveStatus( const char filename[] = "DualRand.conf") const;
// Saves on named file the current engine status.
void restoreStatus( const char filename[] = "DualRand.conf" );
// Reads from named file the last saved engine status and restores it.
void showStatus() const;
// Dumps the current engine status on the screen.
operator HepFloat(); // flat value, without worrying about filling bits
operator unsigned int(); // 32-bit flat value, quickest of all
friend HepStd::ostream & operator<< (HepStd::ostream & os, const DualRand & e);
friend HepStd::istream & operator>> (HepStd::istream & is, DualRand & e);
private:
static HepInt numEngines;
static HepDouble twoToMinus_32;
static HepDouble twoToMinus_53;
static HepDouble nearlyTwoToMinus_54;
void powersOfTwo();
// This generator is composed of two others combined:
class Tausworthe {
public:
Tausworthe();
Tausworthe(unsigned int seed);
operator unsigned int();
void put(HepStd::ostream & os) const;
void get(HepStd::istream & is);
private:
HepInt wordIndex;
unsigned int words[4];
}; // Tausworthe
class IntegerCong {
public:
IntegerCong();
IntegerCong(unsigned int seed, HepInt streamNumber);
operator unsigned int();
void put(HepStd::ostream & os) const;
void get(HepStd::istream & is);
private:
unsigned int state, multiplier, addend;
}; // IntegerCong
Tausworthe tausworthe;
IntegerCong integerCong;
}; // DualRand
#endif // DualRand_h
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