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25 //
26 // G4VBiasingOperation
27 //
28 // Class Description:
29 //
30 // An abstract class to model the behavior of any type of biasing :
31 // physics-based biasing (change of physics process behavior) or non-
32 // physics-based one, like splitting, killing.
33 //
34 // o The change of behavior of a physics process can be:
35 // - a change of the PostStep interaction probabilty, so-called
36 // occurrence biasing
37 // - a change in final state production
38 // - both, provided above two are uncorrelated.
39 // o The change of occurrence is driven by providing a biasing interaction
40 // law (G4VBiasingInteractionLaw) that is used in place of the analog
41 // exponential law.
42 // This change of occurrence is controlled through many handles.
43 // o The change in final state production is made through one single
44 // method the user is fully responsible of.
45 //
46 // o Non-physics-based biasing is controlled by two methods : one to
47 // specify where this biasing should happen, and one for generating
48 // the related final-state.
49 //
50 // Author: Marc Verderi (LLR), November 2013
51 // --------------------------------------------------------------------
52 #ifndef G4VBiasingOperation_hh
53 #define G4VBiasingOperation_hh 1
54
55 #include "globals.hh"
56 #include "G4ForceCondition.hh"
57 #include "G4GPILSelection.hh"
58
59 class G4VParticleChange;
60 class G4Track;
61 class G4Step;
62 class G4VBiasingInteractionLaw;
63 class G4VProcess;
64 class G4BiasingProcessInterface;
65
66 class G4VBiasingOperation
67 {
68 public:
69
70 // -- Constructor:
71 G4VBiasingOperation(const G4String& name);
72
73 // -- destructor:
74 virtual ~G4VBiasingOperation() = default;
75
76 // -----------------------------
77 // -- Interface to sub-classes :
78 // -----------------------------
79 // --
80 // *************************************
81 // ** Methods for physics-based biasing:
82 // *************************************
83 // --
84 // ---- I. Biasing of the process occurrence:
85 // -----------------------------------------
86 // ---- The biasing of the process occurrence regards the occurrence of the PostStepDoIt
87 // ---- behavior. But the weight is manipulated by both AlongStep methods (weight for
88 // ---- non-interaction) and PostStep methods (weight for interaction). For this
89 // ---- reason, occurrence biasing is handled by both AlongStep and PostStep methods.
90 // ----
91 // ---- If the operation is returned to the G4BiasingProcessInterface process by the
92 // ---- ProposeOccurenceBiasingOperation(...)/GetProposedOccurenceBiasingOperation(...) method
93 // ---- of the biasing operator, all methods below will be called for this operation.
94 // ----
95 // ---- I.1) Methods called in at the PostStepGetPhysicalInteractionLength(...) level :
96 // ----
97 // ------ o Main and mandatory method for biasing of the PostStep process biasing occurrence :
98 // ------ - propose an interaction law to be substituted to the process that is biased
99 // ------ - the operation is told which is the G4BiasingProcessInterface calling it with
100 // ------ callingProcess argument.
101 // ------ - the returned law will have to have been sampled prior to be returned as it will be
102 // ------ asked for its GetSampledInteractionLength() by the callingProcess.
103 // ------ - the operation can propose a force condition in the PostStepGPIL (the passed value
104 // ------ to the operation is the one of the wrapped process, if proposeForceCondition is
105 // ------ unchanged, this same value will be used as the biasing foroce condition)
106 virtual const G4VBiasingInteractionLaw*
107 ProvideOccurenceBiasingInteractionLaw( const G4BiasingProcessInterface* /* callingProcess */ ,
108 G4ForceCondition& /* proposeForceCondition */ ) = 0;
109 // ----
110 // ---- I.2) Methods called in at the AlongStepGetPhysicalInteractionLength(...) level :
111 // ----
112 // ------ o Operation can optionnally limit GPIL Along Step:
113 virtual G4double ProposeAlongStepLimit( const G4BiasingProcessInterface* /* callingProcess */ )
114 { return DBL_MAX; }
115
116 // ------ o Operation can propose a GPILSelection in the AlongStepGPIL
117 // ------ this selection superseeded the wrapped process selection
118 // ------ if the wrapped process exists, and if has along methods:
119 virtual G4GPILSelection ProposeGPILSelection( const G4GPILSelection wrappedProcessSelection )
120 { return wrappedProcessSelection; }
121
122 // ----
123 // ---- I.3) Methods called in at the AlongStepDoIt(...) level :
124 // ----
125 // ------ o Helper method to inform the operation of the move made in the along, and related non-interaction weight
126 // ------ applied to the primary track for this move:
127 virtual void AlongMoveBy( const G4BiasingProcessInterface* /* callingProcess */,
128 const G4Step* /* step */,
129 G4double /* weightForNonInteraction */ ) {}
130
131 // ---- II. Biasing of the process post step final state:
132 // ------------------------------------------------------
133 // ------ Mandatory method for biasing of the PostStepDoIt of the wrapped process
134 // ------ holds by the G4BiasingProcessInterface callingProcess.
135 // ------ User has full freedom for the particle change returned, and is reponsible for
136 // ------ the correctness of weights set to tracks.
137 // ------ The forcedBiasedFinalState should be left as is (ie false) in general. In this
138 // ------ way, if an occurrence biasing is also applied in the step, the weight correction
139 // ------ for it will be applied. If returned forceBiasedFinalState is returned true, then
140 // ------ the returned particle change will be returned as is to the stepping. Full
141 // ------ responsibility of the weight correctness is taken by the biasing operation.
142 // ------ The wrappedProcess can be accessed through the G4BiasingProcessInterface if needed.
143 // ------ This can be used in conjunction with an occurrence biasing, provided this final
144 // ------ state biasing is uncorrelated with the occurrence biasing (as single multiplication
145 // ------ of weights occur between these two biasings).
146 virtual G4VParticleChange* ApplyFinalStateBiasing( const G4BiasingProcessInterface* /* callingProcess */,
147 const G4Track* /* track */,
148 const G4Step* /* step */,
149 G4bool& /* forceBiasedFinalState */) = 0;
150
151 // ---- III. Biasing of the process along step final state:
152 // --------------------------------------------------------
153 // ---- Unprovided for now : requires significant developments.
154
155 // ***************************************************
156 // -- Methods for non-physics-based biasing operation:
157 // ***************************************************
158 // ----
159 // ---- If the operation is returned to the G4BiasingProcessInterface process by the
160 // ---- ProposeNonPhysicsBiasingOperation(...)/GetProposedNonPhysicsBiasingOperation(...) method
161 // ---- of the biasing operator, all methods below will be called for this operation.
162 // -----
163 // ---- 1) Method called in at the PostStepGetPhysicalInteractionLength(...) level :
164 // ----
165 // ---- o Return to the distance at which the operation should be applied, or may
166 // ---- play with the force condition flags.
167 virtual G4double DistanceToApplyOperation( const G4Track* /* track */,
168 G4double /* previousStepSize */,
169 G4ForceCondition* /* condition */) = 0;
170 // ----
171 // ---- 2) Method called in at the PostStepDoIt(...) level :
172 // ----
173 // ---- o Generate the final state for biasing (eg: splitting, killing, etc.)
174 virtual G4VParticleChange* GenerateBiasingFinalState( const G4Track* /* track */,
175 const G4Step* /* step */) = 0;
176
177 // ----------------------------------------
178 // -- public interface and utility methods:
179 // ----------------------------------------
180
181 const G4String& GetName() const { return fName; }
182 std::size_t GetUniqueID() const { return fUniqueID; }
183
184 private:
185
186 const G4String fName;
187 // -- better would be to have fUniqueID const, but pb on windows with constructor.
188 std::size_t fUniqueID;
189 };
190
191 #endif
192