Matchbox/Matching/MEMatching.h

0001 // -*- C++ -*-
0002 //
0003 // MEMatching.h is a part of Herwig - A multi-purpose Monte Carlo event generator
0004 // Copyright (C) 2002-2019 The Herwig Collaboration
0005 //
0006 // Herwig is licenced under version 3 of the GPL, see COPYING for details.
0007 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
0008 //
0009 #ifndef Herwig_MEMatching_H
0010 #define Herwig_MEMatching_H
0011 //
0012 // This is the declaration of the MEMatching class.
0013 //
0014
0015 #include "Herwig/MatrixElement/Matchbox/Matching/ShowerApproximation.h"
0016
0017 namespace Herwig {
0018
0019 using namespace ThePEG;
0020
0021 /**
0022  * \ingroup Matchbox
0023  * \author Simon Platzer
0024  *
0025  * \brief MEMatching implements NLO matching with matrix element correction (aka Powheg).
0026  *
0027  */
0028 class MEMatching: public Herwig::ShowerApproximation {
0029
0030 public:
0031
0032   /**
0033    * The default constructor.
0034    */
0035   MEMatching();
0036
0037 public:
0038
0039   /**
0040    * Return true, if this shower approximation will require a
0041    * splitting generator
0042    */
0043   virtual bool needsSplittingGenerator() const { return true; }
0044
0045   /**
0046    * Return true, if this shower approximation will require
0047    * H events
0048    */
0049   virtual bool hasHEvents() const { return restrictPhasespace() || profileScales(); }
0050
0051   /**
0052    * Return true, if this shower approximation will require
0053    * a truncated parton shower
0054    */
0055   virtual bool needsTruncatedShower() const { return theTruncatedShower; }
0056
0057 public:
0058
0059   /**
0060    * Return the shower approximation to the real emission cross
0061    * section for the given pair of Born and real emission
0062    * configurations.
0063    */
0064   virtual CrossSection dSigHatDR() const;
0065
0066   /**
0067    * Return the shower approximation splitting kernel for the given
0068    * pair of Born and real emission configurations in units of the
0069    * Born center of mass energy squared, and including a weight to
0070    * project onto the splitting given by the dipole used.
0071    */
0072   virtual double me2() const;
0073
0074 public:
0075
0076   /** @name Functions used by the persistent I/O system. */
0077   //@{
0078   /**
0079    * Function used to write out object persistently.
0080    * @param os the persistent output stream written to.
0081    */
0082   void persistentOutput(PersistentOStream & os) const;
0083
0084   /**
0085    * Function used to read in object persistently.
0086    * @param is the persistent input stream read from.
0087    * @param version the version number of the object when written.
0088    */
0089   void persistentInput(PersistentIStream & is, int version);
0090   //@}
0091
0092   /**
0093    * The standard Init function used to initialize the interfaces.
0094    * Called exactly once for each class by the class description system
0095    * before the main function starts or
0096    * when this class is dynamically loaded.
0097    */
0098   static void Init();
0099
0100 protected:
0101
0102   /** @name Clone Methods. */
0103   //@{
0104   /**
0105    * Make a simple clone of this object.
0106    * @return a pointer to the new object.
0107    */
0108   virtual IBPtr clone() const;
0109
0110   /** Make a clone of this object, possibly modifying the cloned object
0111    * to make it sane.
0112    * @return a pointer to the new object.
0113    */
0114   virtual IBPtr fullclone() const;
0115   //@}
0116
0117
0118 // If needed, insert declarations of virtual function defined in the
0119 // InterfacedBase class here (using ThePEG-interfaced-decl in Emacs).
0120
0121
0122 private:
0123
0124   /**
0125    * The assignment operator is private and must never be called.
0126    * In fact, it should not even be implemented.
0127    */
0128   MEMatching & operator=(const MEMatching &) = delete;
0129
0130   /**
0131    * True, if a truncated parton shower should be generated
0132    */
0133   bool theTruncatedShower;
0134
0135 };
0136
0137 }
0138
0139 #endif /* Herwig_MEMatching_H */