CLHEP/Random/RandBinomial.h

// $Id: RandBinomial.h,v 1.5 2000/04/17 22:59:49 mf Exp $
// -*- C++ -*-
//
// -----------------------------------------------------------------------
//                             HEP Random
//                         --- RandBinomial ---
//                          class header file
// -----------------------------------------------------------------------

// Class defining methods for shooting binomial distributed random values,
// given a sample size n (default=1) and a probability p (default=0.5).
// Default values are used for operator()().
//
// Valid input values satisfy the relation n*min(p,1-p) > 0. When invalid
// values are presented, the code silently returns -1.0.

// =======================================================================
// John Marraffino - Created: 12th May 1998  Based on the C-Rand package
//                   by Ernst Stadlober and Franz Niederl of the Technical
//                   University of Graz, Austria.
// Gabriele Cosmo  - Removed useless methods and data: 5th Jan 1999
// =======================================================================

#ifndef RandBinomial_h
#define RandBinomial_h 1

#include "CLHEP/Random/Random.h"

class RandBinomial : public HepRandom {

public:

  inline RandBinomial ( HepRandomEngine& anEngine, long n=1,
                                                     HepDouble p=0.5 );
  inline RandBinomial ( HepRandomEngine* anEngine, long n=1,
                                                     HepDouble p=0.5 );
  // These constructors should be used to instantiate a RandBinomial
  // distribution object defining a local engine for it.
  // The static generator will be skipped using the non-static methods
  // defined below.
  // If the engine is passed by pointer the corresponding engine object
  // will be deleted by the RandBinomial destructor.
  // If the engine is passed by reference the corresponding engine object
  // will not be deleted by the RandBinomial destructor.

  virtual ~RandBinomial();
  // Destructor

  // Static methods to shoot random values using the static generator

  static inline HepDouble shoot();

  static HepDouble shoot( long n, HepDouble p );

  static void shootArray ( const HepInt size, HepDouble* vect,
                            long n=1, HepDouble p=0.5 );

  //  Static methods to shoot random values using a given engine
  //  by-passing the static generator.

  static inline HepDouble shoot( HepRandomEngine* anEngine );

  static HepDouble shoot( HepRandomEngine* anEngine, 
                                  long n, HepDouble p );

  static void shootArray ( HepRandomEngine* anEngine, const HepInt size,
                            HepDouble* vect, long n=1,
                            HepDouble p=0.5 );

  //  Methods using the localEngine to shoot random values, by-passing
  //  the static generator.

  inline HepDouble fire();

  HepDouble fire( long n, HepDouble p );
  
  void fireArray ( const HepInt size, HepDouble* vect);
  void fireArray ( const HepInt size, HepDouble* vect,
                   long n, HepDouble p );
  inline HepDouble operator()();
  inline HepDouble operator()( long n, HepDouble p );

private:

  // Private copy constructor. Defining it here disallows use.
  RandBinomial(const RandBinomial& d);

  static HepDouble genBinomial( HepRandomEngine *anEngine, long n, HepDouble p );

  HepRandomEngine* localEngine;
  HepBoolean deleteEngine;
  const long defaultN;
  const HepDouble defaultP;
 
};

#include "CLHEP/Random/RandBinomial.icc"

#endif