musrsim/geant4/spin_rot/src/sr1TabulatedField2D.cc
2008-12-22 17:53:30 +00:00

230 lines
8.8 KiB
C++

#include "sr1TabulatedField2D.hh"
//#include "sr1EventAction.hh" // cks: just to get the event nr. if needed.
#include "sr1Parameters.hh"
sr1TabulatedField2D* sr1TabulatedField2D::pointerToTabulatedField2D=NULL;
sr1TabulatedField2D* sr1TabulatedField2D::GetInstance() {
return pointerToTabulatedField2D;
}
sr1TabulatedField2D::sr1TabulatedField2D( const char* filename, double fieldValue, double lenUnit, double fieldNormalisation )
:ffieldValue(fieldValue),invertX(false),invertZ(false)
{
pointerToTabulatedField2D=this;
G4cout << "pointerToTabulatedField2D="<<pointerToTabulatedField2D<<G4endl;
// double lenUnit= meter;
// double fieldUnit= tesla;
G4cout << "\n-----------------------------------------------------------"
<< "\n Magnetic field"
<< "\n-----------------------------------------------------------"
<< G4endl;
G4cout << " tesla="<<tesla<<G4endl;
G4cout << " Field set to "<< fieldValue/tesla << " T"<< G4endl;
G4cout << "\n ---> " "Reading the field grid from " << filename << " ... " << G4endl;
positionOffset[0]=0;
positionOffset[1]=0;
positionOffset[2]=0;
positionOffset[3]=0;
std::ifstream file( filename ); // Open the file for reading.
// Ignore first blank line
char buffer[256];
// file.getline(buffer,256);
// Read table dimensions
int nDummy;
file >> nx >> nDummy >> nz; // Note dodgy order
G4cout << " [ Number of values x,z: "
<< nx << " " << nz << " ] "
<< G4endl;
// Set up storage space for table
xField.resize( nx );
zField.resize( nx );
int ix, iz;
for (ix=0; ix<nx; ix++) {
xField[ix].resize(nz);
zField[ix].resize(nz);
}
// Ignore other header information
// The first line whose second character is '0' is considered to
// be the last line of the header.
do {
file.getline(buffer,256);
} while ( buffer[1]!='0');
// Read in the data
double xval,yval,zval,bx,bz;
double permeability; // Not used in this example.
for (ix=0; ix<nx; ix++) {
for (iz=0; iz<nz; iz++) {
file >> xval >> yval >> zval >> bx >> bz >> permeability;
if ( ix==0 && iz==0 ) {
minx = xval * lenUnit;
minz = zval * lenUnit;
}
//xField[ix][iy][iz] = bx * fieldUnit * fieldValue;
//zField[ix][iy][iz] = bz * fieldUnit * fieldValue;
// xField[ix][iy][iz] = bx * fieldValue;
// zField[ix][iy][iz] = bz * fieldValue;
xField[ix][iz] = bx*fieldNormalisation;
zField[ix][iz] = bz*fieldNormalisation;
}
}
file.close();
maxx = xval * lenUnit;
maxz = zval * lenUnit;
G4cout << "\n ---> ... done reading " << G4endl;
// G4cout << " Read values of field from file " << filename << G4endl;
G4cout << " ---> assumed the order: x, y, z, Bx, Bz "
<< "\n ---> Min values x,y,z: "
<< minx/cm << " " << minz/cm << " cm "
<< "\n ---> Max values x,y,z: "
<< maxx/cm << " " << maxz/cm << " cm " << G4endl;
// Should really check that the limits are not the wrong way around.
if (maxx < minx) {std::swap(maxx,minx); invertX = true;}
if (maxz < minz) {std::swap(maxz,minz); invertZ = true;}
G4cout << "\nAfter reordering if neccesary"
<< "\n ---> Min values x,y,z: "
<< minx/cm << " " << minz/cm << " cm "
<< " \n ---> Max values x,y,z: "
<< maxx/cm << " " << maxz/cm << " cm ";
dx = maxx - minx;
dz = maxz - minz;
G4cout << "\n ---> Dif values x,z (range): "
<< dx/cm << " " << dz/cm << " cm in z "
<< "\n-----------------------------------------------------------" << G4endl;
}
void sr1TabulatedField2D::GetFieldValue(const double point[4],
double *Bfield ) const
{
// G4cout<<"Tabulated: Field requested at point ("<<point[0]<<","<<point[1]<<","<<point[2]<<")"<<G4endl;
// sr1EventAction* myEventAction= sr1EventAction::GetInstance();
// G4int evNr=myEventAction->GetLatestEventNr();
// G4int evNrKriz=6795; //457; //14250
// if (evNr==evNrKriz) {
// std::cout<<"evNr="<<evNr<<std::endl;
// printf ("for point= %f %f %f B= %10.10f %10.10f %10.10f \n",
// point[0],point[1],point[2],Bfield[0]/tesla,Bfield[1]/tesla,Bfield[2]/tesla);
// }
Bfield[0]=0.; Bfield[1]=0.; Bfield[2]=0.;
double pppoint[4];
pppoint[0]=point[0]+positionOffset[0];
pppoint[1]=point[1]+positionOffset[1];
pppoint[2]=point[2]+positionOffset[2];
pppoint[3]=point[3]+positionOffset[3];
double x = sqrt(pppoint[0]*pppoint[0]+pppoint[1]*pppoint[1]);
double z = fabs(pppoint[2]);
double z_sign = (pppoint[2]>0) ? 1.:-1.;
//if (evNr==evNrKriz) std::cout<<"x ="<<x<<" maxx="<<maxx<<std::endl;
// Check that the point is within the defined region
if ( x<maxx && z<maxz ) {
// if (evNr>evNrKriz) std::cout<<"bol som tu"<<std::endl;
// Position of given point within region, normalized to the range
// [0,1]
double xfraction = (x - minx) / dx;
double zfraction = (z - minz) / dz;
if (invertX) { xfraction = 1 - xfraction;}
if (invertZ) { zfraction = 1 - zfraction;}
// Need addresses of these to pass to modf below.
// modf uses its second argument as an OUTPUT argument.
double xdindex, zdindex;
// Position of the point within the cuboid defined by the
// nearest surrounding tabulated points
double xlocal = ( modf(xfraction*(nx-1), &xdindex));
double zlocal = ( modf(zfraction*(nz-1), &zdindex));
// The indices of the nearest tabulated point whose coordinates
// are all less than those of the given point
int xindex = static_cast<int>(xdindex);
int zindex = static_cast<int>(zdindex);
//cks The following check is necessary - even though xindex and zindex should never be out of range,
// it may happen (due to some rounding error ?). It is better to leave the check here.
if ((xindex<0)||(xindex>(nx-2))) {
std::cout<<"SERIOUS PROBLEM: xindex out of range! xindex="<<xindex<<" x="<<x<<" xfraction="<<xfraction<<std::endl;
if (xindex<0) xindex=0;
else xindex=nx-2;
}
if ((zindex<0)||(zindex>(nz-2))) {
std::cout<<"SERIOUS PROBLEM: zindex out of range! zindex="<<zindex<<" z="<<z<<" zfraction="<<zfraction<<std::endl;
if (zindex<0) zindex=0;
else zindex=nz-2;
}
// Find out whether the muon is decaying. If yes, calculate the field in
// more detail (more precisely).
// The following commented piece of code was not reliable (was indicating the
// proccess "DecayWithSpin" even if there was none).
// G4String processName = G4RunManagerKernel::GetRunManagerKernel()->
// // G4String processName = G4EventManager::GetEventManager()->
// GetTrackingManager()->GetTrack()->GetStep()->
// GetPostStepPoint()->GetProcessDefinedStep()->
// GetProcessName();
// The following seems to be OK:
// if (sr1Parameters::field_DecayWithSpin) {
// sr1Parameters::field_DecayWithSpin=false;
//
// }
// else { // Muon is not decaying, use a fast method of interpolation.
// Interpolate between the neighbouring points
double Bfield_R =
xField[xindex ][zindex ] * (1-xlocal) * (1-zlocal) +
xField[xindex ][zindex+1] * (1-xlocal) * zlocal +
xField[xindex+1][zindex ] * xlocal * (1-zlocal) +
xField[xindex+1][zindex+1] * xlocal * zlocal ;
Bfield[0] = (x>0) ? Bfield_R * (pppoint[0]/x) : 0.;
Bfield[1] = (x>0) ? Bfield_R * (pppoint[1]/x) : 0.;
Bfield[2] =
zField[xindex ][zindex ] * (1-xlocal) * (1-zlocal) +
zField[xindex ][zindex+1] * (1-xlocal) * zlocal +
zField[xindex+1][zindex ] * xlocal * (1-zlocal) +
zField[xindex+1][zindex+1] * xlocal * zlocal ;
Bfield[0] = Bfield[0] * ffieldValue * z_sign;
Bfield[1] = Bfield[1] * ffieldValue * z_sign;
Bfield[2] = Bfield[2] * ffieldValue;
// }
}
// Set some small field if field is almost zero (to avoid internal problems of Geant).
if (sqrt(Bfield[0]*Bfield[0]+Bfield[1]*Bfield[1]+Bfield[2]*Bfield[2])<0.00001*tesla) {
// if (evNr>evNrKriz) std::cout<<"bol som tuna"<<std::endl;
// Bfield[0] = 0.0;
// Bfield[1] = 0.0;
// Bfield[2] = Bfield[2] + 0.00001*tesla;
Bfield[2] = 0.00001*tesla;
}
// Print the field (for debugging)
// if ((point[2]>-0.1*mm)&&(point[2]<0.1*mm)) {
// printf ("for point= %f %f %f B= %10.10f %10.10f %10.10f \n",
// point[0],point[1],point[2],Bfield[0]/tesla,Bfield[1]/tesla,Bfield[2]/tesla);
// }
// if (evNr>evNrKriz) std::cout<<"this is the end"<<std::endl;
}
G4double sr1TabulatedField2D::GetFieldSetValue() {
return ffieldValue;
}
void sr1TabulatedField2D::SetFieldValue(double newFieldValue) {
// // Rescale the magnetic field for a new value of the magnetic field
ffieldValue=newFieldValue;
G4cout<<"sr1TabulatedField2D.cc: ffieldValue changed to="<< ffieldValue/tesla<<"T "<<G4endl;
}