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25 // 22 //
26 // G4ChordFinder implementation <<
27 // 23 //
28 // Author: J.Apostolakis - Design and implemen << 24 // $Id: G4ChordFinder.cc,v 1.36 2003/06/25 09:04:23 japost Exp $
29 // ------------------------------------------- << 25 // GEANT4 tag $Name: geant4-05-02 $
30 << 26 //
31 #include <iomanip> << 27 //
>> 28 // 25.02.97 John Apostolakis, design and implimentation
>> 29 // 05.03.97 V. Grichine , style modification
32 30
33 #include "G4ChordFinder.hh" 31 #include "G4ChordFinder.hh"
34 #include "G4SystemOfUnits.hh" << 32 #include "G4MagIntegratorDriver.hh"
35 #include "G4MagneticField.hh" <<
36 #include "G4Mag_UsualEqRhs.hh" 33 #include "G4Mag_UsualEqRhs.hh"
>> 34 #include "G4ClassicalRK4.hh"
>> 35 // #include "G4Field.hh"
>> 36 // #include "G4MagIntegratorStepper.hh"
37 #include "G4MagIntegratorDriver.hh" 37 #include "G4MagIntegratorDriver.hh"
38 // #include "G4ClassicalRK4.hh" << 38 #include <iomanip>
39 // #include "G4CashKarpRKF45.hh" <<
40 // #include "G4NystromRK4.hh" <<
41 // #include "G4BogackiShampine23.hh" <<
42 // #include "G4BogackiShampine45.hh" <<
43 <<
44 #include "G4DormandPrince745.hh" <<
45 <<
46 // New templated stepper(s) -- avoid virtual c <<
47 #include "G4TDormandPrince45.hh" <<
48 <<
49 // FSAL type driver / steppers ----- <<
50 #include "G4FSALIntegrationDriver.hh" <<
51 #include "G4VFSALIntegrationStepper.hh" <<
52 #include "G4RK547FEq1.hh" <<
53 // #include "G4RK547FEq2.hh" <<
54 // #include "G4RK547FEq3.hh" <<
55 // #include "G4FSALBogackiShampine45.hh" <<
56 // #include "G4FSALDormandPrince745.hh" <<
57 <<
58 // Templated type drivers ----- <<
59 #include "G4IntegrationDriver.hh" <<
60 #include "G4InterpolationDriver.hh" <<
61 <<
62 #include "G4HelixHeum.hh" <<
63 #include "G4BFieldIntegrationDriver.hh" <<
64 <<
65 #include "G4QSSDriverCreator.hh" <<
66 39
67 #include "G4CachedMagneticField.hh" << 40 // For the moment fDeltaChord is a constant!
68 41
69 #include <cassert> << 42 const G4double G4ChordFinder::fDefaultDeltaChord = 3. * mm;
70 #include <memory> <<
71 43
72 G4bool G4ChordFinder::gVerboseCtor = false; <<
73 // ........................................... 44 // ..........................................................................
74 45
75 G4ChordFinder::G4ChordFinder(G4VIntegrationDri << 46 G4ChordFinder::G4ChordFinder( G4MagneticField* theMagField,
76 : fDefaultDeltaChord(0.25 * mm), fIntgrDrive << 47 G4double stepMinimum,
>> 48 G4MagIntegratorStepper* pItsStepper )
>> 49 : fDeltaChord( fDefaultDeltaChord )
77 { 50 {
78 // Simple constructor -- it does not create << 51 // Construct the Chord Finder
79 if( gVerboseCtor ) << 52 // by creating in inverse order the Driver, the Stepper and EqRhs ...
>> 53 G4Mag_EqRhs *pEquation = new G4Mag_UsualEqRhs(theMagField);
>> 54 fEquation = pEquation;
>> 55 fLastStepEstimate_Unconstrained = DBL_MAX; // Should move q, p to
>> 56 // G4FieldTrack ??
>> 57 // --->> Charge Q = 0
>> 58 // --->> Momentum P = 1 NOMINAL VALUES !!!!!!!!!!!!!!!!!!
>> 59
>> 60 if( pItsStepper == 0 )
>> 61 {
>> 62 pItsStepper = fDriversStepper = new G4ClassicalRK4(pEquation);
>> 63 fAllocatedStepper= true;
>> 64 }
>> 65 else
80 { 66 {
81 G4cout << "G4ChordFinder: Simple construct << 67 fAllocatedStepper= false;
82 } 68 }
83 << 69 fIntgrDriver = new G4MagInt_Driver(stepMinimum, pItsStepper,
84 fDeltaChord = fDefaultDeltaChord; // P << 70 pItsStepper->GetNumberOfVariables() );
85 } 71 }
86 72
87 // ........................................... << 73 // ......................................................................
88 74
89 G4ChordFinder::G4ChordFinder( G4MagneticField* << 75 G4ChordFinder::~G4ChordFinder()
90 G4double <<
91 G4MagIntegratorS <<
92 G4int <<
93 : fDefaultDeltaChord(0.25 * mm) <<
94 { 76 {
95 // Construct the Chord Finder << 77 delete fEquation; // fIntgrDriver->pIntStepper->theEquation_Rhs;
96 // by creating in inverse order the Driver, << 78 if( fAllocatedStepper)
97 constexpr G4int nVar6 = 6; // Components i << 79 {
98 << 80 delete fDriversStepper;
99 fDeltaChord = fDefaultDeltaChord; // P << 81 } // fIntgrDriver->pIntStepper;}
>> 82 delete fIntgrDriver;
>> 83 }
100 84
101 G4cout << " G4ChordFinder: stepperDriverId: << 85 // ......................................................................
102 86
103 G4bool useFSALstepper = (stepperDriverId << 87 G4double
104 G4bool useTemplatedStepper= (stepperDriverId << 88 G4ChordFinder::AdvanceChordLimited( G4FieldTrack& yCurrent,
105 G4bool useRegularStepper = (stepperDriverId << 89 G4double stepMax,
106 G4bool useBfieldDriver = (stepperDriverId << 90 G4double epsStep )
107 G4bool useG4QSSDriver = (stepperDriverId << 91 {
108 << 92 G4double stepPossible;
109 if( stepperDriverId == kQss3DriverType) << 93 G4double dyErr;
>> 94 G4FieldTrack yEnd( yCurrent);
>> 95 G4double startCurveLen= yCurrent.GetCurveLength();
>> 96
>> 97 G4double nextStep;
>> 98 // *************
>> 99 stepPossible= FindNextChord(yCurrent, stepMax, yEnd, dyErr, epsStep, &nextStep);
>> 100 // *************
>> 101 G4bool good_advance;
>> 102 if ( dyErr < epsStep * stepPossible )
>> 103 {
>> 104 // Accept this accuracy.
>> 105 yCurrent = yEnd;
>> 106 good_advance = true;
>> 107 }
>> 108 else
110 { 109 {
111 stepperDriverId = kQss2DriverType; << 110 // Advance more accurately to "end of chord"
112 G4cout << " G4ChordFinder: QSS 3 is curren << 111 // ***************
>> 112 good_advance = fIntgrDriver->AccurateAdvance(yCurrent, stepPossible, epsStep, nextStep);
>> 113 // ***************
>> 114 if ( ! good_advance ){
>> 115 // In this case the driver could not do the full distance
>> 116 stepPossible= yCurrent.GetCurveLength()-startCurveLen;
>> 117 }
113 } 118 }
114 119
115 using EquationType = G4Mag_UsualEqRhs; <<
116 <<
117 using TemplatedStepperType = <<
118 G4TDormandPrince45<EquationType,nVar6 <<
119 const char* TemplatedStepperName = <<
120 "G4TDormandPrince745 (templated Dormand- <<
121 <<
122 using RegularStepperType = <<
123 G4DormandPrince745; // 5th order embe <<
124 // G4ClassicalRK4; // The old <<
125 // G4CashKarpRKF45; // First em <<
126 // G4BogackiShampine45; // High eff <<
127 // G4NystromRK4; // Nystrom <<
128 // G4RK547FEq1; // or 2 or 3 <<
129 const char* RegularStepperName = <<
130 "G4DormandPrince745 (aka DOPRI5): 5th/4t <<
131 // "BogackiShampine 45 (Embedded 5th/4th <<
132 // "Nystrom stepper 4th order"; <<
133 <<
134 using NewFsalStepperType = G4DormandPrince74 <<
135 <<
136 const char* NewFSALStepperName = <<
137 "G4RK574FEq1> FSAL 4th/5th order 7-stage <<
138 <<
139 #ifdef G4DEBUG_FIELD 120 #ifdef G4DEBUG_FIELD
140 static G4bool verboseDebug = true; << 121 if( dbg ) G4cerr << "Exiting FindNextChord Limited with:\n yCurrent: "
141 if( verboseDebug ) << 122 << yCurrent<< G4endl;
142 { <<
143 G4cout << "G4ChordFinder 2nd Constructor <<
144 G4cout << " Arguments: " << G4endl <<
145 << " - min step = " << stepMinimum <<
146 << " - stepper ptr provided : " <<
147 << ( pItsStepper==nullptr ? " no <<
148 if( pItsStepper==nullptr ) <<
149 G4cout << " - stepper/driver Id = " << <<
150 << " useFSAL = " << useFSALste <<
151 << " , useTemplated = " << use <<
152 << " , useRegular = " << useRe <<
153 << " , useFSAL = " << useFSALs <<
154 << G4endl; <<
155 } <<
156 #endif 123 #endif
157 124
158 // useHigherStepper = forceHigherEffiencySte << 125 return stepPossible;
>> 126 }
159 127
160 auto pEquation = new G4Mag_UsualEqRhs(theMa << 128 // #define TEST_CHORD_PRINT 1
161 fEquation = pEquation; <<
162 129
163 // G4MagIntegratorStepper* regularStepper = << 130 // ............................................................................
164 // G4VFSALIntegrationStepper* fsalStepper = <<
165 // G4MagIntegratorStepper* oldFSALStepper = <<
166 131
167 G4bool errorInStepperCreation = false; << 132 G4double
>> 133 G4ChordFinder::FindNextChord( const G4FieldTrack yStart,
>> 134 G4double stepMax,
>> 135 G4FieldTrack& yEnd, // Endpoint
>> 136 G4double& dyErrPos, // Error of endpoint
>> 137 G4double epsStep,
>> 138 G4double* pStepForAccuracy)
>> 139 // Returns Length of Step taken
>> 140 {
>> 141 // G4int stepRKnumber=0;
>> 142 G4FieldTrack yCurrent= yStart;
>> 143 G4double stepTrial, stepForAccuracy;
>> 144 G4double dydx[G4FieldTrack::ncompSVEC];
>> 145
>> 146 // 1.) Try to "leap" to end of interval
>> 147 // 2.) Evaluate if resulting chord gives d_chord that is good enough.
>> 148 // 2a.) If d_chord is not good enough, find one that is.
>> 149
>> 150 G4bool validEndPoint= false;
>> 151 G4double dChordStep, lastStepLength; // stepOfLastGoodChord;
168 152
169 std::ostringstream message; // In case of f << 153 fIntgrDriver-> GetDerivatives( yCurrent, dydx ) ;
170 154
171 if( pItsStepper != nullptr ) << 155 G4int noTrials=0;
172 { << 156 const G4double safetyFactor= (1-perThousand); // TO-DO: = 0.975 or 0.95;
173 if( gVerboseCtor ) <<
174 { <<
175 G4cout << " G4ChordFinder: Creating G4I <<
176 << " stepMinimum = " << stepMini <<
177 << " numVar= " << pItsStepper->G <<
178 } <<
179 157
180 // Stepper type is not known - so must us << 158 stepTrial = std::min( stepMax,
181 if(pItsStepper->isQSS()) << 159 safetyFactor * fLastStepEstimate_Unconstrained );
182 { << 160
183 // fIntgrDriver = pItsStepper->build_ << 161 G4double newStepEst_Uncons= 0.0;
184 G4Exception("G4ChordFinder::G4ChordFi << 162 do
185 "GeomField1001", FatalEx << 163 {
186 "Cannot provide QSS ste << 164 G4double stepForChord;
187 } << 165 yCurrent = yStart; // Always start from initial point
188 else << 166
189 { << 167 // ************
190 fIntgrDriver = new G4IntegrationDrive << 168 fIntgrDriver->QuickAdvance( yCurrent, dydx, stepTrial,
191 pItsStepper, << 169 dChordStep, dyErrPos);
192 // Stepper type is not known - so mus << 170 // ************
193 // Non-interpolating driver used by d << 171
194 // WAS: fIntgrDriver = pItsStepper-> << 172 // We check whether the criterion is met here.
195 } << 173 validEndPoint = AcceptableMissDist(dChordStep);
196 // -- Older: << 174 // && (dyErrPos < eps) ;
197 // G4cout << " G4ChordFinder: Creating G4 << 175
198 // Type is not known - so must use old cl << 176 lastStepLength = stepTrial;
199 // fIntgrDriver = new G4MagInt_Driver( st << 177
200 // pItsSt << 178 // This method estimates to step size for a good chord.
201 } << 179 stepForChord = NewStep(stepTrial, dChordStep, newStepEst_Uncons );
202 else if ( useTemplatedStepper ) << 180
203 { << 181 if( ! validEndPoint ) {
204 if( gVerboseCtor ) << 182 if( (stepForChord <= lastStepLength) || (stepTrial<=0.0) )
205 { << 183 stepTrial = stepForChord;
206 G4cout << " G4ChordFinder: Creating Te <<
207 << TemplatedStepperName << G4en <<
208 } <<
209 // RegularStepperType* regularStepper = n <<
210 auto templatedStepper = new TemplatedStep <<
211 // *** *************** <<
212 // <<
213 // Alternative - for G4NystromRK4: <<
214 // = new G4NystromRK4(pEquation, 0.1*mm ) <<
215 fRegularStepperOwned = templatedStepper; <<
216 if( templatedStepper == nullptr ) <<
217 { <<
218 message << "Templated Stepper instanti <<
219 message << "G4ChordFinder: Attempted t <<
220 << TemplatedStepperName << " t <<
221 errorInStepperCreation = true; <<
222 } <<
223 else <<
224 { <<
225 fIntgrDriver = new G4IntegrationDriver <<
226 stepMinimum, templatedStepper, nVar <<
227 if( gVerboseCtor ) <<
228 { <<
229 G4cout << " G4ChordFinder: Using G4 <<
230 } <<
231 } <<
232 <<
233 } <<
234 else if ( useRegularStepper ) // Plain st <<
235 { <<
236 auto regularStepper = new RegularStepperT <<
237 // *** *************** <<
238 fRegularStepperOwned = regularStepper; <<
239 <<
240 if( gVerboseCtor ) <<
241 { <<
242 G4cout << " G4ChordFinder: Creating Dr <<
243 } <<
244 <<
245 if( regularStepper == nullptr ) <<
246 { <<
247 message << "Regular Stepper instantiat <<
248 message << "G4ChordFinder: Attempted t <<
249 << RegularStepperName << " typ <<
250 errorInStepperCreation = true; <<
251 } <<
252 else <<
253 { <<
254 auto dp5= dynamic_cast<G4DormandPrince <<
255 if( dp5 != nullptr ) <<
256 { <<
257 fIntgrDriver = new G4InterpolationD <<
258 stepMinimum, <<
259 if( gVerboseCtor ) <<
260 { <<
261 G4cout << " Using InterpolationD <<
262 } <<
263 } <<
264 else 184 else
265 { << 185 stepTrial *= 0.1;
266 fIntgrDriver = new G4IntegrationDri << 186
267 stepMinimum, << 187 // if(dbg) G4cerr<<"Dchord too big. Try new hstep="<<stepTrial<<G4endl;
268 if( gVerboseCtor ) <<
269 { <<
270 G4cout << " Using IntegrationDri <<
271 } <<
272 } <<
273 } <<
274 } <<
275 else if ( useBfieldDriver ) <<
276 { <<
277 auto regularStepper = new G4DormandPrince <<
278 // *** *************** <<
279 // <<
280 fRegularStepperOwned = regularStepper; <<
281 <<
282 { <<
283 using SmallStepDriver = G4Interpolatio <<
284 using LargeStepDriver = G4IntegrationD <<
285 <<
286 fLongStepper = std::make_unique<G4Heli <<
287 <<
288 fIntgrDriver = new G4BFieldIntegration <<
289 std::make_unique<SmallStepDriver>(st <<
290 regularStepper, regularStepper-> <<
291 std::make_unique<LargeStepDriver>(st <<
292 fLongStepper.get(), regularStepp <<
293 <<
294 if( fIntgrDriver == nullptr) <<
295 { <<
296 message << "Using G4BFieldIntegrati <<
297 << RegularStepperName << " <<
298 message << "Driver instantiation FA <<
299 G4Exception("G4ChordFinder::G4Chord <<
300 "GeomField1001", JustWa <<
301 } <<
302 } <<
303 } <<
304 else if( useG4QSSDriver ) <<
305 { <<
306 if( stepperDriverId == kQss2DriverType ) <<
307 { <<
308 auto qssStepper2 = G4QSSDriverCreator:: <<
309 if( gVerboseCtor ) <<
310 { <<
311 G4cout << "-- Created QSS-2 stepper" <<
312 } <<
313 fIntgrDriver = G4QSSDriverCreator::Crea <<
314 } <<
315 else <<
316 { <<
317 auto qssStepper3 = G4QSSDriverCreator:: <<
318 if( gVerboseCtor ) <<
319 { <<
320 G4cout << "-- Created QSS-3 stepper" <<
321 } <<
322 fIntgrDriver = G4QSSDriverCreator::Crea <<
323 } <<
324 if( gVerboseCtor ) <<
325 { <<
326 G4cout << "-- G4ChordFinder: Using QSS <<
327 } 188 }
>> 189 // #ifdef TEST_CHORD_PRINT
>> 190 // TestChordPrint( noTrials, lastStepLength, dChordStep, stepTrial );
>> 191 // #endif
>> 192
>> 193 noTrials++;
328 } 194 }
329 else << 195 while( ! validEndPoint ); // End of do-while RKD
330 { << 196
331 auto fsalStepper= new NewFsalStepperType << 197 if( newStepEst_Uncons > 0.0 ){
332 // *** ****************** << 198 fLastStepEstimate_Unconstrained= newStepEst_Uncons;
333 fNewFSALStepperOwned = fsalStepper; <<
334 <<
335 if( fsalStepper == nullptr ) <<
336 { <<
337 message << "Stepper instantiation FAIL <<
338 message << "Attempted to instantiate " <<
339 << NewFSALStepperName << " typ <<
340 G4Exception("G4ChordFinder::G4ChordFin <<
341 "GeomField1001", JustWarni <<
342 errorInStepperCreation = true; <<
343 } <<
344 else <<
345 { <<
346 fIntgrDriver = new <<
347 G4FSALIntegrationDriver<NewFsalStep <<
348 fsal <<
349 // ==== Create the driver which k <<
350 <<
351 if( fIntgrDriver == nullptr ) <<
352 { <<
353 message << "Using G4FSALIntegration <<
354 << NewFSALStepperName << G4 <<
355 message << "Integration Driver inst <<
356 G4Exception("G4ChordFinder::G4Chord <<
357 "GeomField1001", JustWa <<
358 } <<
359 } <<
360 } 199 }
361 200
362 // -- Main work is now done << 201 // stepOfLastGoodChord = stepTrial;
363 << 202
364 // Now check that no error occured, and r << 203 if( pStepForAccuracy ){
365 << 204 // Calculate the step size required for accuracy, if it is needed
366 // To test failure to create driver << 205 G4double dyErr_relative = dyErrPos/(epsStep*lastStepLength);
367 // delete fIntgrDriver; << 206 if( dyErr_relative > 1.0 ) {
368 // fIntgrDriver = nullptr; << 207 stepForAccuracy =
369 << 208 fIntgrDriver->ComputeNewStepSize( dyErr_relative,
370 // Detect and report Error conditions << 209 lastStepLength );
371 // << 210 }else{
372 if( errorInStepperCreation || (fIntgrDriver << 211 stepForAccuracy = 0.0; // Convention to show step was ok
373 { <<
374 std::ostringstream errmsg; <<
375 <<
376 if( errorInStepperCreation ) <<
377 { <<
378 errmsg << "ERROR> Failure to create S <<
379 << " ------------------- <<
380 } <<
381 if (fIntgrDriver == nullptr ) <<
382 { <<
383 errmsg << "ERROR> Failure to create I <<
384 << G4endl <<
385 << " ------------------- <<
386 << G4endl; <<
387 } 212 }
388 const std::string BoolName[2]= { "False", << 213 *pStepForAccuracy = stepForAccuracy;
389 errmsg << " Configuration: (constructor <<
390 << " provided Stepper = " << pI <<
391 << " stepper/driver Id = " << step <<
392 << " useTemplated = " << BoolNam <<
393 << " useRegular = " << BoolName[ <<
394 << " useFSAL = " << BoolName[use <<
395 << " using combo BField Driver = <<
396 BoolName[ ! (useFSALstepper <<
397 || useRegularSt <<
398 << G4endl; <<
399 errmsg << message.str(); <<
400 errmsg << "Aborting."; <<
401 G4Exception("G4ChordFinder::G4ChordFinder <<
402 "GeomField0003", FatalExcepti <<
403 } 214 }
404 215
405 assert( ( pItsStepper != nullptr ) << 216 #ifdef TEST_CHORD_PRINT
406 || ( fRegularStepperOwned != nullptr << 217 static int dbg=0;
407 || ( fNewFSALStepperOwned != nullptr << 218 if( dbg )
408 || useG4QSSDriver << 219 G4cout << "ChordF/FindNextChord: NoTrials= " << noTrials
409 ); << 220 << " StepForGoodChord=" << std::setw(10) << stepTrial << G4endl;
410 assert( fIntgrDriver != nullptr ); << 221 #endif
411 } <<
412 222
413 // ........................................... << 223 yEnd= yCurrent;
>> 224 return stepTrial;
>> 225 }
414 226
415 G4ChordFinder::~G4ChordFinder() << 227 // ----------------------------------------------------------------------------
416 { << 228 #if 0
417 delete fEquation; << 229 // #ifdef G4VERBOSE
418 delete fRegularStepperOwned; << 230 if( dbg ) {
419 delete fNewFSALStepperOwned; << 231 G4cerr << "Returned from QuickAdvance with: yCur=" << yCurrent <<G4endl;
420 delete fCachedField; << 232 G4cerr << " dChordStep= "<< dChordStep <<" dyErr=" << dyErr << G4endl;
421 delete fIntgrDriver; <<
422 } 233 }
>> 234 #endif
>> 235 // ----------------------------------------------------------------------------
423 236
424 // ........................................... 237 // ...........................................................................
425 238
426 G4FieldTrack << 239 G4double G4ChordFinder::NewStep(G4double stepTrialOld,
427 G4ChordFinder::ApproxCurvePointS( const G4Fiel << 240 G4double dChordStep, // Curr. dchord achieved
428 const G4Fiel << 241 G4double& stepEstimate_Unconstrained )
429 const G4Fiel << 242 //
430 const G4Thre << 243 // Is called to estimate the next step size, even for successful steps,
431 const G4Thre << 244 // in order to predict an accurate 'chord-sensitive' first step
432 const G4Thre << 245 // which is likely to assist in more performant 'stepping'.
433 G4bool << 246 //
>> 247
434 { 248 {
435 // ApproxCurvePointS is 2nd implementation o << 249 G4double stepTrial;
436 // Use Brent Algorithm (or InvParabolic) whe << 250 static G4double lastStepTrial = 1., lastDchordStep= 1.;
437 // Given a starting curve point A (CurveA_Po << 251
438 // (CurveB_PointVelocity), a point E which i << 252 #if 1
439 // and a point F which is on the curve (fir << 253 // const G4double threshold = 1.21, multiplier = 0.9;
440 // point S on the curve closer to point E. << 254 // 0.9 < 1 / sqrt(1.21)
441 // While advancing towards S utilise 'eps_st <<
442 // relative accuracy of each Step. <<
443 <<
444 G4FieldTrack EndPoint(CurveA_PointVelocity); <<
445 if(!first) { EndPoint = ApproxCurveV; } <<
446 <<
447 G4ThreeVector Point_A,Point_B; <<
448 Point_A=CurveA_PointVelocity.GetPosition(); <<
449 Point_B=CurveB_PointVelocity.GetPosition(); <<
450 <<
451 G4double xa,xb,xc,ya,yb,yc; <<
452 <<
453 // InverseParabolic. AF Intersects (First Pa <<
454 255
455 if(first) << 256 if (dChordStep > 0.0)
456 { 257 {
457 xa=0.; << 258 stepEstimate_Unconstrained = stepTrialOld*sqrt( fDeltaChord / dChordStep );
458 ya=(PointG-Point_A).mag(); << 259 stepTrial = 0.98 * stepEstimate_Unconstrained;
459 xb=(Point_A-CurrentF_Point).mag(); << 260 }
460 yb=-(PointG-CurrentF_Point).mag(); <<
461 xc=(Point_A-Point_B).mag(); <<
462 yc=-(CurrentE_Point-Point_B).mag(); <<
463 } <<
464 else 261 else
465 { 262 {
466 xa=0.; << 263 // Should not update the Unconstrained Step estimate: incorrect!
467 ya=(Point_A-CurrentE_Point).mag(); << 264 stepTrial = stepTrialOld * 2.;
468 xb=(Point_A-CurrentF_Point).mag(); <<
469 yb=(PointG-CurrentF_Point).mag(); <<
470 xc=(Point_A-Point_B).mag(); <<
471 yc=-(Point_B-PointG).mag(); <<
472 if(xb==0.) <<
473 { <<
474 EndPoint = ApproxCurvePointV(CurveA_Poin <<
475 CurrentE_Po <<
476 return EndPoint; <<
477 } <<
478 } 265 }
479 266
480 const G4double tolerance = 1.e-12; << 267 // if ( dChordStep < threshold * fDeltaChord ){
481 if(std::abs(ya)<=tolerance||std::abs(yc)<=to << 268 // stepTrial= stepTrialOld * multiplier;
>> 269 // }
>> 270 if( stepTrial <= 0.001 * stepTrialOld)
>> 271 {
>> 272 if ( dChordStep > 1000.0 * fDeltaChord ){
>> 273 stepTrial= stepTrialOld * 0.03;
>> 274 }else{
>> 275 if ( dChordStep > 100. * fDeltaChord ){
>> 276 stepTrial= stepTrialOld * 0.1;
>> 277 }else{
>> 278 // Try halving the length until dChordStep OK
>> 279 stepTrial= stepTrialOld * 0.5;
>> 280 }
>> 281 }
>> 282 }else if (stepTrial > 1000.0 * stepTrialOld)
482 { 283 {
483 ; // What to do for the moment: return the << 284 stepTrial= 1000.0 * stepTrialOld;
484 // then PropagatorInField will take care <<
485 } 285 }
486 else <<
487 { <<
488 G4double test_step = InvParabolic(xa,ya,xb <<
489 G4double curve; <<
490 if(first) <<
491 { <<
492 curve=std::abs(EndPoint.GetCurveLength() <<
493 -ApproxCurveV.GetCurveLeng <<
494 } <<
495 else <<
496 { <<
497 test_step = test_step - xb; <<
498 curve=std::abs(EndPoint.GetCurveLength() <<
499 -CurveB_PointVelocity.GetC <<
500 xb = (CurrentF_Point-Point_B).mag(); <<
501 } <<
502 <<
503 if(test_step<=0) { test_step=0.1*xb; } <<
504 if(test_step>=xb) { test_step=0.5*xb; } <<
505 if(test_step>=curve){ test_step=0.5*curve; <<
506 <<
507 if(curve*(1.+eps_step)<xb) // Similar to R <<
508 { // G4VIntersect <<
509 test_step=0.5*curve; <<
510 } <<
511 286
512 fIntgrDriver->AccurateAdvance(EndPoint,tes << 287 if( stepTrial == 0.0 ){
513 << 288 stepTrial= 0.000001;
514 #ifdef G4DEBUG_FIELD <<
515 // Printing Brent and Linear Approximation <<
516 // <<
517 G4cout << "G4ChordFinder::ApproxCurvePoint <<
518 << test_step << " EndPoint = " << <<
519 <<
520 // Test Track <<
521 // <<
522 G4FieldTrack TestTrack( CurveA_PointVeloci <<
523 TestTrack = ApproxCurvePointV( CurveA_Poin <<
524 CurveB_Poin <<
525 CurrentE_Po <<
526 G4cout.precision(14); <<
527 G4cout << "G4ChordFinder::BrentApprox = " <<
528 G4cout << "G4ChordFinder::LinearApprox= " <<
529 #endif <<
530 } 289 }
531 return EndPoint; <<
532 } <<
533 290
>> 291 lastStepTrial = stepTrialOld;
>> 292 lastDchordStep= dChordStep;
>> 293 #else
>> 294 if ( dChordStep > 1000. * fDeltaChord ){
>> 295 stepTrial= stepTrialOld * 0.03;
>> 296 }else{
>> 297 if ( dChordStep > 100. * fDeltaChord ){
>> 298 stepTrial= stepTrialOld * 0.1;
>> 299 }else{
>> 300 // Keep halving the length until dChordStep OK
>> 301 stepTrial= stepTrialOld * 0.5;
>> 302 }
>> 303 }
>> 304 #endif
534 305
535 // ........................................... << 306 // A more sophisticated chord-finder could figure out a better
>> 307 // stepTrial, from dChordStep and the required d_geometry
>> 308 // eg
>> 309 // Calculate R, r_helix (eg at orig point)
>> 310 // if( stepTrial < 2 pi R )
>> 311 // stepTrial = R arc_cos( 1 - fDeltaChord / r_helix )
>> 312 // else
>> 313 // ??
>> 314
>> 315 return stepTrial;
>> 316 }
536 317
537 G4FieldTrack G4ChordFinder:: << 318 //
538 ApproxCurvePointV( const G4FieldTrack& CurveA_ << 319 // Given a starting curve point A (CurveA_PointVelocity), a later
539 const G4FieldTrack& CurveB_ << 320 // curve point B (CurveB_PointVelocity) and a point E which is (generally)
540 const G4ThreeVector& Curren << 321 // not on the curve, find and return a point F which is on the curve and
541 G4double eps_step) << 322 // which is close to E. While advancing towards F utilise eps_step
>> 323 // as a measure of the relative accuracy of each Step.
>> 324
>> 325 G4FieldTrack
>> 326 G4ChordFinder::ApproxCurvePointV( const G4FieldTrack& CurveA_PointVelocity,
>> 327 const G4FieldTrack& CurveB_PointVelocity,
>> 328 const G4ThreeVector& CurrentE_Point,
>> 329 G4double eps_step)
542 { 330 {
543 // If r=|AE|/|AB|, and s=true path lenght (A << 331 // 1st implementation:
544 // return the point that is r*s along the cu << 332 // if r=|AE|/|AB|, and s=true path lenght (AB)
545 << 333 // return the point that is r*s along the curve!
546 G4FieldTrack Current_PointVelocity = Curve << 334
>> 335 G4FieldTrack Current_PointVelocity= CurveA_PointVelocity;
547 336
548 G4ThreeVector CurveA_Point= CurveA_PointVel 337 G4ThreeVector CurveA_Point= CurveA_PointVelocity.GetPosition();
549 G4ThreeVector CurveB_Point= CurveB_PointVel 338 G4ThreeVector CurveB_Point= CurveB_PointVelocity.GetPosition();
550 339
551 G4ThreeVector ChordAB_Vector= CurveB_Point 340 G4ThreeVector ChordAB_Vector= CurveB_Point - CurveA_Point;
552 G4ThreeVector ChordAE_Vector= CurrentE_Poin 341 G4ThreeVector ChordAE_Vector= CurrentE_Point - CurveA_Point;
553 342
554 G4double ABdist= ChordAB_Vector.mag(); 343 G4double ABdist= ChordAB_Vector.mag();
555 G4double curve_length; // A curve length 344 G4double curve_length; // A curve length of AB
556 G4double AE_fraction; 345 G4double AE_fraction;
557 346
558 curve_length= CurveB_PointVelocity.GetCurveL 347 curve_length= CurveB_PointVelocity.GetCurveLength()
559 - CurveA_PointVelocity.GetCurveL 348 - CurveA_PointVelocity.GetCurveLength();
560 << 349
561 G4double integrationInaccuracyLimit= std::ma << 350 // const
562 if( curve_length < ABdist * (1. - integratio << 351 G4double integrationInaccuracyLimit= std::max( perMillion, 0.5*eps_step );
563 { << 352 if( curve_length < ABdist * (1. - integrationInaccuracyLimit) ){
564 #ifdef G4DEBUG_FIELD 353 #ifdef G4DEBUG_FIELD
565 G4cerr << " Warning in G4ChordFinder::Appr 354 G4cerr << " Warning in G4ChordFinder::ApproxCurvePoint: "
566 << G4endl 355 << G4endl
567 << " The two points are further apa 356 << " The two points are further apart than the curve length "
568 << G4endl 357 << G4endl
569 << " Dist = " << ABdist 358 << " Dist = " << ABdist
570 << " curve length = " << curve_leng 359 << " curve length = " << curve_length
571 << " relativeDiff = " << (curve_len 360 << " relativeDiff = " << (curve_length-ABdist)/ABdist
572 << G4endl; 361 << G4endl;
573 if( curve_length < ABdist * (1. - 10*eps_s << 362 if( curve_length < ABdist * (1. - 10*eps_step) ) {
574 { << 363 G4cerr << " ERROR: the size of the above difference"
575 std::ostringstream message; << 364 << " exceeds allowed limits. Aborting." << G4endl;
576 message << "Unphysical curve length." << << 365 G4Exception("G4ChordFinder::ApproxCurvePoint > Unphysical curve length.");
577 << "The size of the above differ <<
578 << G4endl <<
579 << "Aborting."; <<
580 G4Exception("G4ChordFinder::ApproxCurveP <<
581 FatalException, message); <<
582 } 366 }
583 #endif 367 #endif
584 // Take default corrective action: adjust << 368 // Take default corrective action:
585 // NOTE: this case only happens for relati << 369 // --> adjust the maximum curve length.
586 // curve_length = ABdist; << 370 // NOTE: this case only happens for relatively straight paths.
>> 371 curve_length = ABdist;
587 } 372 }
588 373
589 G4double new_st_length; << 374 G4double new_st_length;
590 375
591 if ( ABdist > 0.0 ) << 376 if ( ABdist > 0.0 ){
592 { <<
593 AE_fraction = ChordAE_Vector.mag() / ABdi 377 AE_fraction = ChordAE_Vector.mag() / ABdist;
594 } << 378 }else{
595 else <<
596 { <<
597 AE_fraction = 0.5; 379 AE_fraction = 0.5; // Guess .. ?;
598 #ifdef G4DEBUG_FIELD 380 #ifdef G4DEBUG_FIELD
599 G4cout << "Warning in G4ChordFinder::Appr << 381 G4cout << "Warning in G4ChordFinder::ApproxCurvePoint:"
600 << " A and B are the same point!" 382 << " A and B are the same point!" << G4endl
601 << " Chord AB length = " << ChordA 383 << " Chord AB length = " << ChordAE_Vector.mag() << G4endl
602 << G4endl; 384 << G4endl;
603 #endif 385 #endif
604 } 386 }
605 387
606 if( (AE_fraction> 1.0 + perMillion) || (AE_f << 388 if( (AE_fraction> 1.0 + perMillion) || (AE_fraction< 0.) ){
607 { <<
608 #ifdef G4DEBUG_FIELD 389 #ifdef G4DEBUG_FIELD
609 G4cerr << " G4ChordFinder::ApproxCurvePoin << 390 G4cerr << " G4ChordFinder::ApproxCurvePointV - Warning:"
610 << " Anomalous condition:AE > AB or 391 << " Anomalous condition:AE > AB or AE/AB <= 0 " << G4endl
611 << " AE_fraction = " << AE_fract 392 << " AE_fraction = " << AE_fraction << G4endl
612 << " Chord AE length = " << Chord 393 << " Chord AE length = " << ChordAE_Vector.mag() << G4endl
613 << " Chord AB length = " << ABdis 394 << " Chord AB length = " << ABdist << G4endl << G4endl;
614 G4cerr << " OK if this condition occurs af 395 G4cerr << " OK if this condition occurs after a recalculation of 'B'"
615 << G4endl << " Otherwise it is an e 396 << G4endl << " Otherwise it is an error. " << G4endl ;
616 #endif 397 #endif
617 // This course can now result if B has be 398 // This course can now result if B has been re-evaluated,
618 // without E being recomputed (1 July 99) << 399 // without E being recomputed (1 July 99)
619 // In this case this is not a "real error << 400 // In this case this is not a "real error" - but it undesired
620 // and we cope with it by a default corre << 401 // and we cope with it by a default corrective action ...
621 // <<
622 AE_fraction = 0.5; 402 AE_fraction = 0.5; // Default value
623 } 403 }
624 404
625 new_st_length = AE_fraction * curve_length; << 405 new_st_length= AE_fraction * curve_length;
626 406
627 if ( AE_fraction > 0.0 ) << 407 G4bool good_advance;
628 { << 408 if ( AE_fraction > 0.0 ) {
629 fIntgrDriver->AccurateAdvance(Current_Poi << 409 good_advance =
630 new_st_leng << 410 fIntgrDriver->AccurateAdvance(Current_PointVelocity,
631 // << 411 new_st_length,
>> 412 eps_step ); // Relative accuracy
632 // In this case it does not matter if it 413 // In this case it does not matter if it cannot advance the full distance
633 } 414 }
634 415
635 // If there was a memory of the step_length << 416 // If there was a memory of the step_length actually require at the start
636 // of the integration Step, this could be re 417 // of the integration Step, this could be re-used ...
637 418
638 G4cout.precision(14); <<
639 <<
640 return Current_PointVelocity; 419 return Current_PointVelocity;
641 } 420 }
642 421
643 // ........................................... << 422 void
644 << 423 G4ChordFinder::TestChordPrint( G4int noTrials,
645 std::ostream& operator<<( std::ostream& os, co << 424 G4int lastStepTrial,
>> 425 G4double dChordStep,
>> 426 G4double nextStepTrial )
646 { 427 {
647 // Dumping the state of G4ChordFinder << 428 G4int oldprec= G4cout.precision(5);
648 os << "State of G4ChordFinder : " << std::e << 429 G4cout << " ChF/fnc: notrial " << std::setw( 3) << noTrials
649 os << " delta_chord = " << cf.fDeltaCh << 430 << " this_step= " << std::setw(10) << lastStepTrial;
650 os << " Default d_c = " << cf.fDefault << 431 if( fabs( (dChordStep / fDeltaChord) - 1.0 ) < 0.001 ){
651 << 432 G4cout.precision(8);
652 os << " stats-verbose = " << cf.fStatsVe << 433 }else{ G4cout.precision(6); }
653 << 434 G4cout << " dChordStep= " << std::setw(12) << dChordStep;
654 return os; << 435 if( dChordStep > fDeltaChord ) { G4cout << " d+"; }
>> 436 else { G4cout << " d-"; }
>> 437 G4cout.precision(5);
>> 438 G4cout << " new_step= " << std::setw(10)
>> 439 << fLastStepEstimate_Unconstrained
>> 440 << " new_step_constr= " << std::setw(10)
>> 441 << lastStepTrial << G4endl;
>> 442 G4cout << " nextStepTrial = " << std::setw(10) << nextStepTrial << G4endl;
>> 443 G4cout.precision(oldprec);
655 } 444 }
656 445