BeamProfileVtxGenerator.cc

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#include "IOMC/EventVertexGenerators/interface/BeamProfileVtxGenerator.h"
#include "FWCore/Utilities/interface/Exception.h"

#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

#include "CLHEP/Geometry/Transform3D.h"
#include "CLHEP/Random/RandFlat.h"
#include "CLHEP/Random/RandGaussQ.h"
#include "CLHEP/Units/GlobalSystemOfUnits.h"
#include "CLHEP/Units/GlobalPhysicalConstants.h"
#include "HepMC/SimpleVector.h"

#include<fstream>
#include<string>

BeamProfileVtxGenerator::BeamProfileVtxGenerator(const edm::ParameterSet & p) :
  BaseEvtVtxGenerator(p) {
  
  meanX(p.getParameter<double>("BeamMeanX")*cm);
  meanY(p.getParameter<double>("BeamMeanY")*cm);
  beamPos(p.getParameter<double>("BeamPosition")*cm);
  sigmaX(p.getParameter<double>("BeamSigmaX")*cm);
  sigmaY(p.getParameter<double>("BeamSigmaY")*cm);
  double fMinEta = p.getParameter<double>("MinEta");
  double fMaxEta = p.getParameter<double>("MaxEta");
  double fMinPhi = p.getParameter<double>("MinPhi");
  double fMaxPhi = p.getParameter<double>("MaxPhi");
  eta(0.5*(fMinEta+fMaxEta));
  phi(0.5*(fMinPhi+fMaxPhi));
  psi(p.getParameter<double>("Psi"));
  nBinx = p.getParameter<int>("BinX");
  nBiny = p.getParameter<int>("BinY");
  ffile = p.getParameter<bool>("UseFile");
  fTimeOffset = p.getParameter<double>("TimeOffset")*ns*c_light;
  
  if (ffile) {
    std::string file = p.getParameter<std::string>("File");
    std::ifstream is(file.c_str(), std::ios::in);
    if (is) {
      double elem,sum=0;
      while (!is.eof()) {
    is >> elem;
        fdistn.push_back(elem);
    sum += elem;
      }
      if (((int)(fdistn.size())) >= nBinx*nBiny) {
    double last = 0;
    for (unsigned int i=0; i<fdistn.size(); i++) {
      fdistn[i] /= sum;
      fdistn[i] += last;
      last       = fdistn[i];
    }
    setType(false);
      } else {
    ffile = false;
      }
    } else {
      ffile = false;
    }
  } 
  if (!ffile) {
    setType(p.getParameter<bool>("GaussianProfile"));
  }

  edm::LogInfo("VertexGenerator") << "BeamProfileVtxGenerator: with "
                  << "beam along eta = " << fEta 
                  << " (Theta = " << fTheta/deg 
                  << ") phi = " << fPhi/deg 
                  << ") psi = " << fPsi/deg 
                  << " centred at (" << fMeanX << ", " 
                  << fMeanY << ", "  << fMeanZ << ") "
                  << "and spread (" << fSigmaX << ", "
                  << fSigmaY << ") of type Gaussian = "
                  << fType << " use file " << ffile;
  if (ffile) 
    edm::LogInfo("VertexGenerator") << "With " << nBinx << " bins "
                    << " along X and " << nBiny 
                    << " bins along Y";
}

BeamProfileVtxGenerator::~BeamProfileVtxGenerator() {
}


//Hep3Vector * BeamProfileVtxGenerator::newVertex() {
HepMC::FourVector* BeamProfileVtxGenerator::newVertex(CLHEP::HepRandomEngine* engine) {
  double aX, aY;
  if (ffile) {
    double r1 = engine->flat();
    int ixy = 0, ix, iy;
    for (unsigned int i=0; i<fdistn.size(); i++) {
      if (r1 > fdistn[i]) ixy = i+1;
    }
    if (ixy >= nBinx*nBiny) {
      ix = nBinx-1; iy = nBiny-1;
    } else {
      ix = ixy%nBinx; iy = (ixy-ix)/nBinx;
    }
    aX = 0.5*(2*ix-nBinx+2*engine->flat())*fSigmaX + fMeanX ;
    aY = 0.5*(2*iy-nBiny+2*engine->flat())*fSigmaY + fMeanY ;
  } else {
    if (fType) {
      aX = fSigmaX*CLHEP::RandGaussQ::shoot(engine) + fMeanX;
      aY = fSigmaY*CLHEP::RandGaussQ::shoot(engine) + fMeanY;
    } else {
      aX = CLHEP::RandFlat::shoot(engine, -0.5*fSigmaX, 0.5*fSigmaX) + fMeanX ;
      aY = CLHEP::RandFlat::shoot(engine, -0.5*fSigmaY, 0.5*fSigmaY) + fMeanY;
    }
  }

  double xp, yp, zp ;
  if( 2.*M_PI < fabs(fPsi) )
  {
     xp = -aX*cos(fTheta)*cos(fPhi) +aY*sin(fPhi) +fMeanZ*sin(fTheta)*cos(fPhi);
     yp = -aX*cos(fTheta)*sin(fPhi) -aY*cos(fPhi) +fMeanZ*sin(fTheta)*sin(fPhi);
     zp =  aX*sin(fTheta)                         +fMeanZ*cos(fTheta);
  }
  else // for endcap testbeam, use 3rd angle psi
  {
     const HepGeom::Vector3D<double>  av ( aX, aY, fMeanZ ) ;

/*
     static const double kRadToDeg ( 180./M_PI ) ;
     std::cout<<"theta = "<<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          <<fTheta*kRadToDeg<<", phi="<<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          << fPhi*kRadToDeg <<", PSI="<<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          <<fPsi*kRadToDeg<<std::endl ;
*/
     const HepGeom::RotateZ3D R1 ( fPhi - M_PI ) ;
     const HepGeom::Point3D<double>  xUnit ( 0,1,0 ) ;
     const HepGeom::Point3D<double>  zUnit ( 0,0,1 ) ;
     const HepGeom::Transform3D RXRZ ( HepGeom::Rotate3D( -fTheta, R1*xUnit )*R1 ) ;
     const HepGeom::Transform3D TRF ( HepGeom::Rotate3D(fPsi,RXRZ*zUnit)*RXRZ ) ;
/*
     std::cout<<"\n\n$$$$$$$$$$$Transform="
          <<" thetaZ = "<<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          <<TRF.getRotation().thetaZ()*kRadToDeg
          <<", phiZ = "<<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          <<TRF.getRotation().phiZ()*kRadToDeg
          <<", thetaY = "<<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          <<TRF.getRotation().thetaY()*kRadToDeg
          <<", phiY = "<<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          <<TRF.getRotation().phiY()*kRadToDeg
          <<", thetaX = "<<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          <<TRF.getRotation().thetaX()*kRadToDeg
          <<", phiX = "<<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          <<TRF.getRotation().phiX()*kRadToDeg
          <<std::setw(7) << std::setiosflags( std::ios::fixed ) << std::setprecision(5)
          <<TRF.getTranslation()<<std::endl ;
*/
     const HepGeom::Vector3D<double>  pv ( TRF*av ) ;

     xp = pv.x() ;
     yp = pv.y() ;
     zp = pv.z() ;
  }
  //if (fVertex == 0) fVertex = new CLHEP::Hep3Vector;
  //fVertex->set(xp, yp, zp);
  if (fVertex == 0 ) fVertex = new HepMC::FourVector() ;
  fVertex->set(xp, yp, zp, fTimeOffset );

  LogDebug("VertexGenerator") << "BeamProfileVtxGenerator: Vertex created "
                  << "at (" << xp << ", " << yp << ", "
                  << zp << ", " << fTimeOffset << ")";
  return fVertex;
}

void BeamProfileVtxGenerator::sigmaX(double s) { 

  if (s>=0) {
    fSigmaX = s; 
  } else {
    edm::LogWarning("VertexGenerator") << "Warning BeamProfileVtxGenerator:"
                       << " Illegal resolution in X " << s
                       << "- set to default value 0 cm";
    fSigmaX = 0;
  }
}

void BeamProfileVtxGenerator::sigmaY(double s) { 

  if (s>=0) {
    fSigmaY = s; 
  } else {
    edm::LogWarning("VertexGenerator") << "Warning BeamProfileVtxGenerator:"
                       << " Illegal resolution in Y " << s
                       << "- set to default value 0 cm";
    fSigmaY = 0;
  }
}

void BeamProfileVtxGenerator::eta(double s) { 
  fEta   = s; 
  fTheta = 2.0*atan(exp(-fEta));
}

void BeamProfileVtxGenerator::setType(bool s) { 
  fType = s;
}