| Geant4 Cross Reference |
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25 //
26 // Class G4PropagatorInField
27 //
28 // class description:
29 //
30 // This class performs the navigation/propagation of a particle/track
31 // in a magnetic field. The field is in general non-uniform.
32 // For the calculation of the path, it relies on the class G4ChordFinder.
33
34 // History:
35 // -------
36 // 25.10.96 John Apostolakis, design and implementation
37 // 25.03.97 John Apostolakis, adaptation for G4Transportation and cleanup
38 // 8.11.02 John Apostolakis, changes to enable use of safety in intersecting
39 // ---------------------------------------------------------------------------
40 #ifndef G4PropagatorInField_hh
41 #define G4PropagatorInField_hh 1
42
43 #include "G4Types.hh"
44
45 #include <vector>
46
47 #include "G4FieldTrack.hh"
48 #include "G4FieldManager.hh"
49 #include "G4VIntersectionLocator.hh"
50
51 class G4ChordFinder;
52
53 class G4Navigator;
54 class G4VPhysicalVolume;
55 class G4VCurvedTrajectoryFilter;
56
57 class G4PropagatorInField
58 {
59
60 public: // with description
61
62 G4PropagatorInField( G4Navigator* theNavigator,
63 G4FieldManager* detectorFieldMgr,
64 G4VIntersectionLocator* vLocator = nullptr );
65 ~G4PropagatorInField();
66
67 G4double ComputeStep( G4FieldTrack& pFieldTrack,
68 G4double pCurrentProposedStepLength,
69 G4double& pNewSafety,
70 G4VPhysicalVolume* pPhysVol = nullptr,
71 G4bool canRelaxDeltaChord = false);
72 // Compute the next geometric Step
73
74 inline G4ThreeVector EndPosition() const;
75 inline G4ThreeVector EndMomentumDir() const;
76 inline G4bool IsParticleLooping() const;
77 // Return the state after the Step
78
79 inline G4double GetEpsilonStep() const;
80 // Relative accuracy for current Step (Calc.)
81 inline void SetEpsilonStep(G4double newEps);
82 // The ratio DeltaOneStep()/h_current_step
83
84 G4FieldManager* FindAndSetFieldManager(G4VPhysicalVolume* pCurrentPhysVol);
85 // Set (and return) the correct field manager (global or local),
86 // if it exists.
87 // Should be called before ComputeStep is called;
88 // Currently, ComputeStep will call it, if it has not been called.
89
90 inline G4ChordFinder* GetChordFinder();
91
92 G4int SetVerboseLevel( G4int verbose );
93 inline G4int GetVerboseLevel() const;
94 inline G4int Verbose() const;
95 inline void CheckMode(G4bool mode);
96
97 inline void SetVerboseTrace( G4bool enable );
98 inline G4bool GetVerboseTrace();
99 // Tracing key parts of Compute Step
100
101 inline G4int GetMaxLoopCount() const;
102 inline void SetMaxLoopCount( G4int new_max );
103 // A maximum for the number of substeps that a particle can take.
104 // Above this number it is signaled as 'looping'.
105
106 void printStatus( const G4FieldTrack& startFT,
107 const G4FieldTrack& currentFT,
108 G4double requestStep,
109 G4double safety,
110 G4int step,
111 G4VPhysicalVolume* startVolume);
112 // Print Method - useful mostly for debugging.
113
114 inline G4FieldTrack GetEndState() const;
115
116 inline G4double GetMinimumEpsilonStep() const; // Min for relative accuracy
117 inline void SetMinimumEpsilonStep( G4double newEpsMin ); // of any step
118 inline G4double GetMaximumEpsilonStep() const;
119 inline void SetMaximumEpsilonStep( G4double newEpsMax );
120 // The 4 above methods are now obsolescent but *for now* will work
121 // They are being replaced by same-name methods in G4FieldManager,
122 // allowing the specialisation in different volumes.
123 // Their new behaviour is to change the values for the global field
124 // manager
125
126 void SetLargestAcceptableStep( G4double newBigDist );
127 G4double GetLargestAcceptableStep();
128 void ResetLargestAcceptableStep();
129 // Obtain / change the size of the largest step the method will undertake
130 // Reset method uses the world volume's
131
132 G4double GetMaxStepSizeMultiplier();
133 void SetMaxStepSizeMultiplier(G4double vm);
134 // Control extra Multiplier parameter for limiting long steps.
135 G4double GetMinBigDistance();
136 void SetMinBigDistance(G4double val);
137 // Control minimum 'directional' distance in case of too-large step
138
139 void SetTrajectoryFilter(G4VCurvedTrajectoryFilter* filter);
140 // Set the filter that examines & stores 'intermediate'
141 // curved trajectory points. Currently only position is stored.
142
143 std::vector<G4ThreeVector>* GimmeTrajectoryVectorAndForgetIt() const;
144 // Access the points which have passed by the filter.
145 // Responsibility for deleting the points lies with the client.
146 // This method MUST BE called exactly ONCE per step.
147
148 void ClearPropagatorState();
149 // Clear all the State of this class and its current associates
150 // --> the current field manager & chord finder will also be called
151
152 inline void SetDetectorFieldManager( G4FieldManager* newGlobalFieldManager );
153 // Update this (dangerous) state -- for the time being
154
155 inline void SetUseSafetyForOptimization( G4bool );
156 inline G4bool GetUseSafetyForOptimization();
157 // Toggle & view parameter for using safety to discard
158 // unneccesary calls to navigator (thus 'optimising' performance)
159 inline G4bool IntersectChord( const G4ThreeVector& StartPointA,
160 const G4ThreeVector& EndPointB,
161 G4double& NewSafety,
162 G4double& LinearStepLength,
163 G4ThreeVector& IntersectionPoint);
164 // Intersect the chord from StartPointA to EndPointB
165 // and return whether an intersection occurred
166 // NOTE: Safety is changed!
167
168 inline G4bool IsFirstStepInVolume();
169 inline G4bool IsLastStepInVolume();
170 inline void PrepareNewTrack();
171
172 inline G4VIntersectionLocator* GetIntersectionLocator();
173 inline void SetIntersectionLocator(G4VIntersectionLocator* pLocator );
174 // Change or get the object which calculates the exact
175 // intersection point with the next boundary
176
177 inline G4int GetIterationsToIncreaseChordDistance() const;
178 inline void SetIterationsToIncreaseChordDistance(G4int numIters);
179 // Control the parameter which enables the temporary 'relaxation'
180 // which ensures that chord segments are short enough so that
181 // their sagitta is small than delta-chord parameter.
182 // The Set method increases the value of delta-chord temporarily,
183 // doubling it once the number of iterations substeps reach
184 // value of 'IncreaseChordDistanceThreshold'. It is also doubled
185 // again every time the iteration count reaches a multiple of this
186 // value.
187 // Note: delta-chord is reset to its original value at the end of
188 // each call to ComputeStep.
189
190 public: // without description
191
192 inline G4double GetDeltaIntersection() const;
193 inline G4double GetDeltaOneStep() const;
194
195 inline G4FieldManager* GetCurrentFieldManager();
196 inline G4EquationOfMotion* GetCurrentEquationOfMotion();
197 // Auxiliary methods - their results can/will change during propagation
198
199 inline void SetNavigatorForPropagating(G4Navigator* SimpleOrMultiNavigator);
200 inline G4Navigator* GetNavigatorForPropagating();
201
202 inline void SetThresholdNoZeroStep( G4int noAct,
203 G4int noHarsh,
204 G4int noAbandon );
205 inline G4int GetThresholdNoZeroSteps( G4int i );
206
207 inline G4double GetZeroStepThreshold();
208 inline void SetZeroStepThreshold( G4double newLength );
209
210 void RefreshIntersectionLocator();
211 // Update the Locator with parameters from this class
212 // and from current field manager
213
214 protected: // without description
215
216 void PrintStepLengthDiagnostic( G4double currentProposedStepLength,
217 G4double decreaseFactor,
218 G4double stepTrial,
219 const G4FieldTrack& aFieldTrack);
220
221 void ReportLoopingParticle( G4int count, G4double StepTaken,
222 G4double stepRequest, const char* methodName,
223 const G4ThreeVector& momentumVec,
224 G4VPhysicalVolume* physVol);
225 void ReportStuckParticle(G4int noZeroSteps, G4double proposedStep,
226 G4double lastTriedStep, G4VPhysicalVolume* physVol);
227
228 private:
229
230 // ----------------------------------------------------------------------
231 // DATA Members
232 // ----------------------------------------------------------------------
233
234 // ==================================================================
235 // INVARIANTS - Must not change during tracking
236
237 // ** PARAMETERS -----------
238 G4int fMax_loop_count = 1000;
239 // Limit for the number of sub-steps taken in one call to ComputeStep
240 G4int fIncreaseChordDistanceThreshold = 100;
241 G4bool fUseSafetyForOptimisation = true;
242 // (false) is less sensitive to incorrect safety
243
244 // Thresholds for identifying "abnormal" cases - which cause looping
245 //
246 G4int fActionThreshold_NoZeroSteps = 2; // Threshold # - above it act
247 G4int fSevereActionThreshold_NoZeroSteps = 10; // Threshold # to act harshly
248 G4int fAbandonThreshold_NoZeroSteps = 50; // Threshold # to abandon
249 G4double fZeroStepThreshold = 0.0;
250 // Threshold *length* for counting of tiny or 'zero' steps
251
252 // Parameters related to handling of very large steps which
253 // occur typically in large volumes with vacuum or very thin gas
254 G4double fLargestAcceptableStep;
255 // Maximum size of a step - for optimization (and to avoid problems)
256 G4double fMaxStepSizeMultiplier = 3;
257 // Multiplier for directional exit distance used as extra long-step limit
258 G4double fMinBigDistance= 100. ; // * CLHEP::mm
259 // Minimum distance added to directional exit distance
260 // ** End of PARAMETERS -----
261
262 G4double kCarTolerance;
263 // Geometrical tolerance defining surface thickness
264
265 G4bool fAllocatedLocator; // Book-keeping
266
267 // --------------------------------------------------------
268 // ** Dependent Objects - to which work is delegated
269
270 G4FieldManager* fDetectorFieldMgr;
271 // The Field Manager of the whole Detector. (default)
272
273 G4VIntersectionLocator* fIntersectionLocator;
274 // Refines candidate intersection
275
276 G4VCurvedTrajectoryFilter* fpTrajectoryFilter = nullptr;
277 // The filter encapsulates the algorithm which selects which
278 // intermediate points should be stored in a trajectory.
279 // When it is NULL, no intermediate points will be stored.
280 // Else PIF::ComputeStep must submit (all) intermediate
281 // points it calculates, to this filter. (jacek 04/11/2002)
282
283 G4Navigator* fNavigator;
284 // Set externally - only by tracking / run manager
285 //
286 // ** End of Dependent Objects ----------------------------
287
288 // End of INVARIANTS
289 // ==================================================================
290
291 // STATE information
292 // -----------------
293 G4FieldManager* fCurrentFieldMgr;
294 // The Field Manager of the current volume (may be the global)
295 G4bool fSetFieldMgr = false; // Has it been set for the current step?
296
297 // Parameters of current step
298 G4double fEpsilonStep; // Relative accuracy of current Step
299 G4FieldTrack End_PointAndTangent; // End point storage
300 G4bool fParticleIsLooping = false;
301 G4int fNoZeroStep = 0; // Count of zero Steps
302
303 // State used for Optimisation
304 G4double fFull_CurveLen_of_LastAttempt = -1;
305 G4double fLast_ProposedStepLength = -1;
306 // Previous step information -- for use in adjust step size
307 G4ThreeVector fPreviousSftOrigin;
308 G4double fPreviousSafety = 0.0;
309 // Last safety origin & value: for optimisation
310
311 G4int fVerboseLevel = 0;
312 G4bool fVerbTracePiF = false;
313 G4bool fCheck = false;
314 // For debugging purposes
315
316 G4bool fFirstStepInVolume = true;
317 G4bool fLastStepInVolume = true;
318 G4bool fNewTrack = true;
319 };
320
321 // Inline methods
322 //
323 #include "G4PropagatorInField.icc"
324
325 #endif
326