BLGlobalField Class Reference

#include <BLGlobalField.hh>

List of all members.

Detailed Description

BLGlobalField - handles the global ElectroMagnetic field.

There is a single BLGlobalField object.

The field from each individual beamline element is given by a BLElementField object. Any number of overlapping BLElementField objects can be added to the global field. Any element command that represents an element with an EM field must add the appropriate BLElementField to the global BLGlobalField object.

Public Member Functions

void GetFieldValue (const G4double *point, G4double *field) const
 GetFieldValue() returns the field value at a given point[]. field is really field[6]: Bx,By,Bz,Ex,Ey,Ez. point[] is in global coordinates: x,y,z,t. Uses the field map for solenoids, when possible.
void getFieldValue (G4ThreeVector &pos, G4double t, G4ThreeVector &B, G4ThreeVector &E)
G4bool DoesFieldChangeEnergy () const
 DoesFieldChangeEnergy() returns true.
void addElementField (const BLElementField *f)
 addElementField() adds the BLElementField object for a single element to the global field.
void clear ()
 clear() removes all BLElementField-s from the global object, and destroys them. Used before the geometry is completely re-created.
void zeroEfield (bool v)
 zeroEfield() sets the flag that forces the Efield to be zero everywhere. Used for ICOOL-style reference particle tracking.

Static Public Member Functions

static BLGlobalField * getObject ()
 getObject() returns the single BLGlobalField object. It is constructed, if necessary.

Protected Member Functions

 BLGlobalField ()
 ~BLGlobalField ()
 BLGlobalField (const BLGlobalField &)
BLGlobalField & operator= (const BLGlobalField &)
void setupArray ()

Protected Attributes

std::vector< const
BLElementField * > 		fields
const BLElementField ** fp
bool first
int nfp
bool forceEfieldZero

Static Protected Attributes

static BLGlobalField * object = 0

Constructor & Destructor Documentation

BLGlobalField::BLGlobalField (  )  [protected]

References clear(), first, forceEfieldZero, fp, BLParam::getDouble(), nfp, and Param.

Referenced by getObject().

00046                              : G4ElectroMagneticField(), fields()
00047 {
00048         first = true;
00049         fp = 0;
00050         nfp = 0;
00051         forceEfieldZero = false;
00052 
00053         clear();
00054 
00055         // Get transportation, field, and propagator  managers
00056         G4TransportationManager  *pTransportMgr= 
00057                G4TransportationManager::GetTransportationManager();
00058         G4FieldManager* fieldMgr = pTransportMgr->GetFieldManager();
00059         G4PropagatorInField *pFieldPropagator =
00060                                         pTransportMgr->GetPropagatorInField(); 
00061 
00062         // Need to SetFieldChangesEnergy to account for a time varying electric
00063         // field (r.f. fields)
00064         fieldMgr->SetFieldChangesEnergy(true);
00065 
00066         // Construct equation of motion of particles through e.m. fields
00067         G4EqMagElectricField *fEquationE = new G4EqMagElectricField(this);
00068 
00069 #ifdef STUB
00070         // Set the field
00071         fieldMgr->SetDetectorField(this);
00072 
00073         // Choose a stepper for integration of the equation of motion
00074         G4MagIntegratorStepper *pStepper = new G4ClassicalRK4(fEquationE,8);
00075         //G4MagIntegratorStepper *pStepper = new G4SimpleRunge(fEquationE,8);
00076      
00077         // Create a cord finder providing the (global field, min step length,
00078         // a pointer to the stepper)
00079 #ifndef GEANT4_NOT4_6
00080         G4double min_step = Param.getDouble("minStep");
00081         G4ChordFinder* pChordFinder = new G4ChordFinder((G4MagneticField *)this,min_step,pStepper);
00082 #else
00083         G4double min_step = Param.getDouble("minStep");
00084         G4ChordFinder* pChordFinder = new G4ChordFinder(this,min_step,pStepper);
00085 #endif
00086 
00087 #else   //STUB
00088         G4double min_step = Param.getDouble("minStep");
00089         G4MagIntegratorStepper *pStepper = new G4ClassicalRK4(fEquationE,8);
00090         fieldMgr->SetDetectorField(this);
00091         G4MagInt_Driver *fIntgrDriver = new G4MagInt_Driver(min_step, 
00092                                 pStepper, pStepper->GetNumberOfVariables() ); 
00093         G4ChordFinder *pChordFinder = new G4ChordFinder(fIntgrDriver); 
00094         fieldMgr->SetChordFinder( pChordFinder ); 
00095 #endif  //STUB
00096 
00097         // Set accuracy parameters
00098         G4double delta_chord = Param.getDouble("deltaChord");
00099         pChordFinder->SetDeltaChord( delta_chord );
00100         G4double delta_onestep = Param.getDouble("deltaOneStep");
00101         fieldMgr->SetAccuraciesWithDeltaOneStep(delta_onestep);
00102         G4double delta_intersection = Param.getDouble("deltaIntersection");
00103         fieldMgr->SetDeltaIntersection(delta_intersection); 
00104         G4double eps_min = Param.getDouble("epsMin");
00105         G4double eps_max = Param.getDouble("epsMax");
00106         pFieldPropagator->SetMinimumEpsilonStep(eps_min);
00107         pFieldPropagator->SetMaximumEpsilonStep(eps_max);
00108 //      G4cout << "Accuracy Parameters:" <<
00109 //              " MinStep=" << min_step <<
00110 //              " DeltaChord=" << delta_chord <<
00111 //              " DeltaOneStep=" << delta_onestep << G4endl;
00112 //      G4cout << "                    " <<
00113 //              " DeltaIntersection=" << delta_intersection <<
00114 //              " EpsMin=" << eps_min <<
00115 //              " EpsMax=" << eps_max <<  G4endl;
00116         fieldMgr->SetChordFinder(pChordFinder);
00117 
00118         // set object
00119         object = this;
00120 }

BLGlobalField::~BLGlobalField (  )  [protected]

References clear().

00123 {
00124         clear();
00125 }

BLGlobalField::BLGlobalField ( const BLGlobalField &   )  [protected]

Member Function Documentation

BLGlobalField& BLGlobalField::operator= ( const BLGlobalField &   )  [protected]

void BLGlobalField::setupArray (  )  [protected]

References fields, first, fp, and nfp.

00178 {
00179         first = false;
00180         nfp = fields.size();
00181         fp = new const BLElementField *[nfp+1]; // add 1 so it's never 0
00182         for(int i=0; i<nfp; ++i)
00183                 fp[i] = fields[i];
00184 }

BLGlobalField * BLGlobalField::getObject (  )  [static]

getObject() returns the single BLGlobalField object. It is constructed, if necessary.

References BLGlobalField(), and object.

Referenced by BLTrackNTuple::appendTrack(), BLCMDprobefield::callback(), BLCMDfieldntuple::callback(), BLCMDfieldlines::callback(), BLCMDspacechargelw::command(), BLCMDspacecharge::command(), BLCMDcollective::command(), BLManager::Construct(), BLCMDsolenoid::construct(), BLCMDrfdevice::construct(), BLCMDpillbox::construct(), BLCMDmultipole::construct(), BLCMDidealsectorbend::construct(), BLCMDhelicalharmonic::construct(), BLCMDhelicaldipole::construct(), BLCMDgenericquad::construct(), BLCMDgenericbend::construct(), BLCMDfieldmap::construct(), BLCMDfieldexpr::construct(), BLCMDprintfield::do_cylinder(), BLCMDprintfield::do_grid(), BLCMDprintfield::do_points(), BLCMDprintfield::do_print(), BLCMDtracker::fitTrack(), LiLensField::LiLensField(), Bug1021::PostStepGetPhysicalInteractionLength(), BLCMDreference::PostUserTrackingAction(), BLCMDreference::PreUserTrackingAction(), BLEvaluator::setTrackVariables(), BLManager::steppingVerbosePrint(), RFdeviceField::UserSteppingAction(), and BLCMDtracker::UserZSteppingAction().

00128 {
00129         if(!object) new BLGlobalField();
00130         return object;
00131 }

void BLGlobalField::GetFieldValue ( const G4double *  point,
G4double *  field 
) const

GetFieldValue() returns the field value at a given point[]. field is really field[6]: Bx,By,Bz,Ex,Ey,Ez. point[] is in global coordinates: x,y,z,t. Uses the field map for solenoids, when possible.

References BLElementField::addFieldValue(), first, forceEfieldZero, fp, BLElementField::isInBoundingBox(), and nfp.

Referenced by BLTrackNTuple::appendTrack(), BLCMDprobefield::callback(), BLCMDfieldntuple::callback(), BLCMDcollective::collectiveStep(), BLCMDprintfield::do_points(), BLCMDprintfield::do_print(), BLCMDtracker::fitTrack(), getFieldValue(), Bug1021::PostStepGetPhysicalInteractionLength(), BLEvaluator::setTrackVariables(), BLManager::steppingVerbosePrint(), RFdeviceField::UserSteppingAction(), and BLCMDtracker::UserZSteppingAction().

00134 {
00135         // NOTE: this routine dominates the CPU time for tracking.
00136         // The test case is the MICE beamline + detector, which has 38 
00137         // entries in fields[].
00138         // Using bounding boxes sped it up by a factor of 8 (13 ev/sec => 
00139         // 100 ev/sec).
00140         // Using the simple array fp[] instead of fields[] directly sped
00141         // it up by an additional factor of two (200 ev/sec).
00142         // Making this a friend of BLElementField and putting the code for
00143         // isInBoundingBox() inline here didn't help at all.
00144 
00145         field[0] = field[1] = field[2] = field[3] = field[4] = field[5] = 0.0;
00146         // protect against Geant4 bug that calls us with point[] NaN.
00147         if(point[0] != point[0]) return;
00148 
00149         if(first)               // (can't use nfp or fp, as they may change)
00150                 ((BLGlobalField*)this)->setupArray();   // (cast away const)
00151 
00152         for(int i=0; i<nfp; ++i) {
00153                 const BLElementField *p = fp[i];
00154                 if(p->isInBoundingBox(point))
00155                         p->addFieldValue(point,field);
00156         }
00157 
00158         if(forceEfieldZero) {
00159                 field[3] = field[4] = field[5] = 0.0;
00160         }
00161 }

void BLGlobalField::getFieldValue ( G4ThreeVector &  pos,
G4double  t,
G4ThreeVector &  B,
G4ThreeVector &  E 
) [inline]

References GetFieldValue().

Referenced by BLCMDfieldlines::bmag(), BLCMDfieldlines::callback(), and BLCMDfieldlines::generateOneFieldLine().

00062                                                                           {
00063                 G4double point[4], field[6];
00064                 point[0]=pos[0]; point[1]=pos[1]; point[2]=pos[2],point[3]=t;
00065                 GetFieldValue(point,field);
00066                 B.setX(field[0]); B.setY(field[1]); B.setZ(field[2]);
00067                 E.setX(field[3]); E.setY(field[4]); E.setZ(field[5]);
00068         }

G4bool BLGlobalField::DoesFieldChangeEnergy (  )  const [inline]

DoesFieldChangeEnergy() returns true. 

00071 { return true; }

void BLGlobalField::addElementField ( const BLElementField *  f  )  [inline]

addElementField() adds the BLElementField object for a single element to the global field.

References fields.

Referenced by BLCMDspacechargelw::command(), BLCMDspacecharge::command(), BLCMDsolenoid::construct(), BLCMDrfdevice::construct(), BLCMDpillbox::construct(), BLCMDmultipole::construct(), BLCMDidealsectorbend::construct(), BLCMDhelicalharmonic::construct(), BLCMDhelicaldipole::construct(), BLCMDgenericquad::construct(), BLCMDgenericbend::construct(), BLCMDfieldmap::construct(), BLCMDfieldexpr::construct(), and LiLensField::LiLensField().

00076                 { fields.push_back(f); }

void BLGlobalField::clear (  ) 

clear() removes all BLElementField-s from the global object, and destroys them. Used before the geometry is completely re-created.

References fields, first, fp, and nfp.

Referenced by BLGlobalField(), and ~BLGlobalField().

00164 {
00165         std::vector<const BLElementField *>::iterator i;
00166         for(i=fields.begin(); i!=fields.end(); ++i) {
00167                 delete *i;
00168         }
00169         fields.clear();
00170 
00171         if(fp) delete fp;
00172         first = true;
00173         fp = 0;
00174         nfp = 0;
00175 }

void BLGlobalField::zeroEfield ( bool  v  )  [inline]

zeroEfield() sets the flag that forces the Efield to be zero everywhere. Used for ICOOL-style reference particle tracking.

References forceEfieldZero.

Referenced by BLCMDreference::PostUserTrackingAction(), and BLCMDreference::PreUserTrackingAction().

00085 { forceEfieldZero = v; }

Member Data Documentation

std::vector<const BLElementField *> BLGlobalField::fields [protected]

Referenced by addElementField(), clear(), and setupArray().

const BLElementField** BLGlobalField::fp [protected]

Referenced by BLGlobalField(), clear(), GetFieldValue(), and setupArray().

bool BLGlobalField::first [protected]

Referenced by BLGlobalField(), clear(), GetFieldValue(), and setupArray().

int BLGlobalField::nfp [protected]

Referenced by BLGlobalField(), clear(), GetFieldValue(), and setupArray().

bool BLGlobalField::forceEfieldZero [protected]

Referenced by BLGlobalField(), GetFieldValue(), and zeroEfield().

BLGlobalField * BLGlobalField::object = 0 [static, protected]

Referenced by getObject().

The documentation for this class was generated from the following files:
g4beamline