G4VImportanceAlgorithm.hh

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// G4VImportanceAlgorithm
//
// Class description:
//
// This is an interface used by importance sampling to get the 
// number of copies and weight a mother particle should be split 
// into when crossing a boundary of "importance cells". 
// The interface defines the input to be the ratio of the pre over
// the post importance and the weight of the mother track.
// It returns a struct containing the number of copies (including 
// the mother track) to be produced and the weight of each track.
// A user defined algorithm deriving from this interface may be used
// by the importance sampling.
 
// Author: Michael Dressel (CERN), 2002
// ----------------------------------------------------------------------
#ifndef G4VIMPORTANCEALGORITHM_HH
#define G4VIMPORTANCEALGORITHM_HH
 
#include "G4Nsplit_Weight.hh"
 
/**
 * @brief G4VImportanceAlgorithm is an interface used by importance sampling
 * to get the number of copies and weight a mother particle should be split 
 * into when crossing a boundary of "importance cells". 
 * The interface defines the input to be the ratio of the pre over the post
 * importance and the weight of the mother track.
 * It returns a struct containing the number of copies (including the mother
 * track) to be produced and the weight of each track.
 * A user defined algorithm deriving from this interface may be used by the
 * importance sampling.
 */
 
class G4VImportanceAlgorithm
{
  public:
 
    /**
     * Default Constructor and Destructor.
     */
    G4VImportanceAlgorithm() = default;
    virtual ~G4VImportanceAlgorithm() = default;
 
    /**
     * Calculates the number of tracks and their weight according to the
     * pre and post importance value and the weight of the mother track.
     *  @param[in] ipre "pre" importance value.
     *  @param[in] ipost "post" importance value.
     *  @param[in] init_w Initial weight value.
     *  @returns A struct containing the number of copies (including the
     *           mother track) to be produced and the weight of each track.
     */
    virtual G4Nsplit_Weight Calculate(G4double ipre,
                                      G4double ipost,
                                      G4double init_w) const = 0;
};
 
#endif