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geant4/source/externals/clhep/include/CLHEP/Random/DualRand.h
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2018-06-29 10:58:11 +02:00

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// $Id:$
// -*- 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
// Mark Fischler methods for distrib. instance save/restore 12/8/04
// Mark Fischler methods for anonymous save/restore 12/27/04
// Mark Fischler - methods for vector save/restore 3/7/05
// =======================================================================
#ifndef DualRand_h
#define DualRand_h
#include "CLHEP/Random/RandomEngine.h"
namespace CLHEP {
/**
* @author
* @ingroup random
*/
class DualRand: public HepRandomEngine {
public:
DualRand();
DualRand(long seed);
DualRand(std::istream & is);
DualRand(int rowIndex, int colIndex);
virtual ~DualRand();
// let the compiler generate the copy constructors
//DualRand(const DualRand & p);
//DualRand & operator=(const DualRand & p);
double flat();
// Returns a pseudo random number between 0 and 1
// (excluding the end points)
void flatArray(const int size, double * vect);
// Fills an array "vect" of specified size with flat random values.
void setSeed(long seed, int);
// Sets the state of the algorithm according to seed.
void setSeeds(const long * seeds, int);
// 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 double(); // Returns same as flat()
operator float(); // flat value, without worrying about filling bits
operator unsigned int(); // 32-bit flat value, quickest of all
virtual std::ostream & put (std::ostream & os) const;
virtual std::istream & get (std::istream & is);
static std::string beginTag ( );
virtual std::istream & getState ( std::istream & is );
std::string name() const;
static std::string engineName() {return "DualRand";}
std::vector<unsigned long> put () const;
bool get (const std::vector<unsigned long> & v);
bool getState (const std::vector<unsigned long> & v);
static const unsigned int VECTOR_STATE_SIZE = 9;
private:
// This generator is composed of two others combined:
class Tausworthe {
public:
Tausworthe();
Tausworthe(unsigned int seed);
operator unsigned int();
void put(std::ostream & os) const;
void put(std::vector<unsigned long> & v) const;
void get(std::istream & is);
bool get(std::vector<unsigned long>::const_iterator & iv);
private:
int wordIndex;
unsigned int words[4];
}; // Tausworthe
class IntegerCong {
public:
IntegerCong();
IntegerCong(unsigned int seed, int streamNumber);
operator unsigned int();
void put(std::ostream & os) const;
void put(std::vector<unsigned long> & v) const;
void get(std::istream & is);
bool get(std::vector<unsigned long>::const_iterator & iv);
private:
unsigned int state, multiplier, addend;
}; // IntegerCong
int numEngines;
Tausworthe tausworthe;
IntegerCong integerCong;
}; // DualRand
} // namespace CLHEP
#endif // DualRand_h