G4SPSRandomGenerator.cc

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//
//
// MODULE:        G4SPSRandomGenerator.cc
//
// Version:      1.0
// Date:         5/02/04
// Author:       Fan Lei 
// Organisation: QinetiQ ltd.
// Customer:     ESA/ESTEC
//
//
// CHANGE HISTORY
// --------------
//
//
// Version 1.0, 05/02/2004, Fan Lei, Created.
//    Based on the G4GeneralParticleSource class in Geant4 v6.0
//
//
#include "G4PrimaryParticle.hh"
#include "G4Event.hh"
#include "Randomize.hh"
#include <cmath>
#include "G4TransportationManager.hh"
#include "G4VPhysicalVolume.hh"
#include "G4PhysicalVolumeStore.hh"
#include "G4ParticleTable.hh"
#include "G4ParticleDefinition.hh"
#include "G4IonTable.hh"
#include "G4Ions.hh"
#include "G4TrackingManager.hh"
#include "G4Track.hh"

#include "G4SPSRandomGenerator.hh"

//G4SPSRandomGenerator* G4SPSRandomGenerator::instance = 0;

G4SPSRandomGenerator::G4SPSRandomGenerator()
{
        // Initialise all variables

        // Bias variables
        XBias = false;
        IPDFXBias = false;
        YBias = false;
        IPDFYBias = false;
        ZBias = false;
        IPDFZBias = false;
        ThetaBias = false;
        IPDFThetaBias = false;
        PhiBias = false;
        IPDFPhiBias = false;
        EnergyBias = false;
        IPDFEnergyBias = false;
        PosThetaBias = false;
        IPDFPosThetaBias = false;
        PosPhiBias = false;
        IPDFPosPhiBias = false;
        bweights[0] = bweights[1] = bweights[2] = bweights[3] = bweights[4]
                        = bweights[5] = bweights[6] = bweights[7] = bweights[8] = 1.;
        verbosityLevel = 0;
}

G4SPSRandomGenerator::~G4SPSRandomGenerator() {
}

//G4SPSRandomGenerator* G4SPSRandomGenerator::getInstance ()
//{
//  if (instance == 0) instance = new G4SPSRandomGenerator();
//  return instance;
//}

// Biasing methods

void G4SPSRandomGenerator::SetXBias(G4ThreeVector input) {
        G4double ehi, val;
        ehi = input.x();
        val = input.y();
        XBiasH.InsertValues(ehi, val);
        XBias = true;
}

void G4SPSRandomGenerator::SetYBias(G4ThreeVector input) {
        G4double ehi, val;
        ehi = input.x();
        val = input.y();
        YBiasH.InsertValues(ehi, val);
        YBias = true;
}

void G4SPSRandomGenerator::SetZBias(G4ThreeVector input) {
        G4double ehi, val;
        ehi = input.x();
        val = input.y();
        ZBiasH.InsertValues(ehi, val);
        ZBias = true;
}

void G4SPSRandomGenerator::SetThetaBias(G4ThreeVector input) {
        G4double ehi, val;
        ehi = input.x();
        val = input.y();
        ThetaBiasH.InsertValues(ehi, val);
        ThetaBias = true;
}

void G4SPSRandomGenerator::SetPhiBias(G4ThreeVector input) {
        G4double ehi, val;
        ehi = input.x();
        val = input.y();
        PhiBiasH.InsertValues(ehi, val);
        PhiBias = true;
}

void G4SPSRandomGenerator::SetEnergyBias(G4ThreeVector input) {
        G4double ehi, val;
        ehi = input.x();
        val = input.y();
        EnergyBiasH.InsertValues(ehi, val);
        EnergyBias = true;
}

void G4SPSRandomGenerator::SetPosThetaBias(G4ThreeVector input) {
        G4double ehi, val;
        ehi = input.x();
        val = input.y();
        PosThetaBiasH.InsertValues(ehi, val);
        PosThetaBias = true;
}

void G4SPSRandomGenerator::SetPosPhiBias(G4ThreeVector input) {
        G4double ehi, val;
        ehi = input.x();
        val = input.y();
        PosPhiBiasH.InsertValues(ehi, val);
        PosPhiBias = true;
}

void G4SPSRandomGenerator::ReSetHist(G4String atype) {
        if (atype == "biasx") {
                XBias = false;
                IPDFXBias = false;
                XBiasH = IPDFXBiasH = ZeroPhysVector;
        } else if (atype == "biasy") {
                YBias = false;
                IPDFYBias = false;
                YBiasH = IPDFYBiasH = ZeroPhysVector;
        } else if (atype == "biasz") {
                ZBias = false;
                IPDFZBias = false;
                ZBiasH = IPDFZBiasH = ZeroPhysVector;
        } else if (atype == "biast") {
                ThetaBias = false;
                IPDFThetaBias = false;
                ThetaBiasH = IPDFThetaBiasH = ZeroPhysVector;
        } else if (atype == "biasp") {
                PhiBias = false;
                IPDFPhiBias = false;
                PhiBiasH = IPDFPhiBiasH = ZeroPhysVector;
        } else if (atype == "biase") {
                EnergyBias = false;
                IPDFEnergyBias = false;
                EnergyBiasH = IPDFEnergyBiasH = ZeroPhysVector;
        } else if (atype == "biaspt") {
                PosThetaBias = false;
                IPDFPosThetaBias = false;
                PosThetaBiasH = IPDFPosThetaBiasH = ZeroPhysVector;
        } else if (atype == "biaspp") {
                PosPhiBias = false;
                IPDFPosPhiBias = false;
                PosPhiBiasH = IPDFPosPhiBiasH = ZeroPhysVector;
        } else {
                G4cout << "Error, histtype not accepted " << G4endl;
        }
}

G4double G4SPSRandomGenerator::GenRandX() {
        if (verbosityLevel >= 1)
                G4cout << "In GenRandX" << G4endl;
        if (XBias == false) {
                // X is not biased
                G4double rndm = G4UniformRand();
                return (rndm);
        } else {
                // X is biased
                if (IPDFXBias == false) {
                        // IPDF has not been created, so create it
                        G4double bins[1024], vals[1024], sum;
                        G4int ii;
                        G4int maxbin = G4int(XBiasH.GetVectorLength());
                        bins[0] = XBiasH.GetLowEdgeEnergy(size_t(0));
                        vals[0] = XBiasH(size_t(0));
                        sum = vals[0];
                        for (ii = 1; ii < maxbin; ii++) {
                                bins[ii] = XBiasH.GetLowEdgeEnergy(size_t(ii));
                                vals[ii] = XBiasH(size_t(ii)) + vals[ii - 1];
                                sum = sum + XBiasH(size_t(ii));
                        }

                        for (ii = 0; ii < maxbin; ii++) {
                                vals[ii] = vals[ii] / sum;
                                IPDFXBiasH.InsertValues(bins[ii], vals[ii]);
                        }
                        // Make IPDFXBias = true
                        IPDFXBias = true;
                }
                // IPDF has been create so carry on
                G4double rndm = G4UniformRand();

                // Calculate the weighting: Find the bin that the determined
                // rndm is in and the weigthing will be the difference in the
                // natural probability (from the x-axis) divided by the
                // difference in the biased probability (the area).
                size_t numberOfBin = IPDFXBiasH.GetVectorLength();
                G4int biasn1 = 0;
                G4int biasn2 = numberOfBin / 2;
                G4int biasn3 = numberOfBin - 1;
                while (biasn1 != biasn3 - 1) {
                        if (rndm > IPDFXBiasH(biasn2))
                                biasn1 = biasn2;
                        else
                                biasn3 = biasn2;
                        biasn2 = biasn1 + (biasn3 - biasn1 + 1) / 2;
                }
                // retrieve the areas and then the x-axis values
                bweights[0] = IPDFXBiasH(biasn2) - IPDFXBiasH(biasn2 - 1);
                G4double xaxisl = IPDFXBiasH.GetLowEdgeEnergy(size_t(biasn2 - 1));
                G4double xaxisu = IPDFXBiasH.GetLowEdgeEnergy(size_t(biasn2));
                G4double NatProb = xaxisu - xaxisl;
                //G4cout << "X Bin weight " << bweights[0] << " " << rndm << G4endl;
                //G4cout << "lower and upper xaxis vals "<<xaxisl<<" "<<xaxisu<<G4endl;
                bweights[0] = NatProb / bweights[0];
                if (verbosityLevel >= 1)
                        G4cout << "X bin weight " << bweights[0] << " " << rndm << G4endl;
                return (IPDFXBiasH.GetEnergy(rndm));
        }
}

G4double G4SPSRandomGenerator::GenRandY() {
        if (verbosityLevel >= 1)
                G4cout << "In GenRandY" << G4endl;
        if (YBias == false) {
                // Y is not biased
                G4double rndm = G4UniformRand();
                return (rndm);
        } else {
                // Y is biased
                if (IPDFYBias == false) {
                        // IPDF has not been created, so create it
                        G4double bins[1024], vals[1024], sum;
                        G4int ii;
                        G4int maxbin = G4int(YBiasH.GetVectorLength());
                        bins[0] = YBiasH.GetLowEdgeEnergy(size_t(0));
                        vals[0] = YBiasH(size_t(0));
                        sum = vals[0];
                        for (ii = 1; ii < maxbin; ii++) {
                                bins[ii] = YBiasH.GetLowEdgeEnergy(size_t(ii));
                                vals[ii] = YBiasH(size_t(ii)) + vals[ii - 1];
                                sum = sum + YBiasH(size_t(ii));
                        }

                        for (ii = 0; ii < maxbin; ii++) {
                                vals[ii] = vals[ii] / sum;
                                IPDFYBiasH.InsertValues(bins[ii], vals[ii]);
                        }
                        // Make IPDFYBias = true
                        IPDFYBias = true;
                }
                // IPDF has been create so carry on
                G4double rndm = G4UniformRand();
                size_t numberOfBin = IPDFYBiasH.GetVectorLength();
                G4int biasn1 = 0;
                G4int biasn2 = numberOfBin / 2;
                G4int biasn3 = numberOfBin - 1;
                while (biasn1 != biasn3 - 1) {
                        if (rndm > IPDFYBiasH(biasn2))
                                biasn1 = biasn2;
                        else
                                biasn3 = biasn2;
                        biasn2 = biasn1 + (biasn3 - biasn1 + 1) / 2;
                }
                bweights[1] = IPDFYBiasH(biasn2) - IPDFYBiasH(biasn2 - 1);
                G4double xaxisl = IPDFYBiasH.GetLowEdgeEnergy(size_t(biasn2 - 1));
                G4double xaxisu = IPDFYBiasH.GetLowEdgeEnergy(size_t(biasn2));
                G4double NatProb = xaxisu - xaxisl;
                bweights[1] = NatProb / bweights[1];
                if (verbosityLevel >= 1)
                        G4cout << "Y bin weight " << bweights[1] << " " << rndm << G4endl;
                return (IPDFYBiasH.GetEnergy(rndm));
        }
}

G4double G4SPSRandomGenerator::GenRandZ() {
        if (verbosityLevel >= 1)
                G4cout << "In GenRandZ" << G4endl;
        if (ZBias == false) {
                // Z is not biased
                G4double rndm = G4UniformRand();
                return (rndm);
        } else {
                // Z is biased
                if (IPDFZBias == false) {
                        // IPDF has not been created, so create it
                        G4double bins[1024], vals[1024], sum;
                        G4int ii;
                        G4int maxbin = G4int(ZBiasH.GetVectorLength());
                        bins[0] = ZBiasH.GetLowEdgeEnergy(size_t(0));
                        vals[0] = ZBiasH(size_t(0));
                        sum = vals[0];
                        for (ii = 1; ii < maxbin; ii++) {
                                bins[ii] = ZBiasH.GetLowEdgeEnergy(size_t(ii));
                                vals[ii] = ZBiasH(size_t(ii)) + vals[ii - 1];
                                sum = sum + ZBiasH(size_t(ii));
                        }

                        for (ii = 0; ii < maxbin; ii++) {
                                vals[ii] = vals[ii] / sum;
                                IPDFZBiasH.InsertValues(bins[ii], vals[ii]);
                        }
                        // Make IPDFZBias = true
                        IPDFZBias = true;
                }
                // IPDF has been create so carry on
                G4double rndm = G4UniformRand();
                //      size_t weight_bin_no = IPDFZBiasH.FindValueBinLocation(rndm);
                size_t numberOfBin = IPDFZBiasH.GetVectorLength();
                G4int biasn1 = 0;
                G4int biasn2 = numberOfBin / 2;
                G4int biasn3 = numberOfBin - 1;
                while (biasn1 != biasn3 - 1) {
                        if (rndm > IPDFZBiasH(biasn2))
                                biasn1 = biasn2;
                        else
                                biasn3 = biasn2;
                        biasn2 = biasn1 + (biasn3 - biasn1 + 1) / 2;
                }
                bweights[2] = IPDFZBiasH(biasn2) - IPDFZBiasH(biasn2 - 1);
                G4double xaxisl = IPDFZBiasH.GetLowEdgeEnergy(size_t(biasn2 - 1));
                G4double xaxisu = IPDFZBiasH.GetLowEdgeEnergy(size_t(biasn2));
                G4double NatProb = xaxisu - xaxisl;
                bweights[2] = NatProb / bweights[2];
                if (verbosityLevel >= 1)
                        G4cout << "Z bin weight " << bweights[2] << " " << rndm << G4endl;
                return (IPDFZBiasH.GetEnergy(rndm));
        }
}

G4double G4SPSRandomGenerator::GenRandTheta() {
        if (verbosityLevel >= 1) {
                G4cout << "In GenRandTheta" << G4endl;
                G4cout << "Verbosity " << verbosityLevel << G4endl;
        }
        if (ThetaBias == false) {
                // Theta is not biased
                G4double rndm = G4UniformRand();
                return (rndm);
        } else {
                // Theta is biased
                if (IPDFThetaBias == false) {
                        // IPDF has not been created, so create it
                        G4double bins[1024], vals[1024], sum;
                        G4int ii;
                        G4int maxbin = G4int(ThetaBiasH.GetVectorLength());
                        bins[0] = ThetaBiasH.GetLowEdgeEnergy(size_t(0));
                        vals[0] = ThetaBiasH(size_t(0));
                        sum = vals[0];
                        for (ii = 1; ii < maxbin; ii++) {
                                bins[ii] = ThetaBiasH.GetLowEdgeEnergy(size_t(ii));
                                vals[ii] = ThetaBiasH(size_t(ii)) + vals[ii - 1];
                                sum = sum + ThetaBiasH(size_t(ii));
                        }

                        for (ii = 0; ii < maxbin; ii++) {
                                vals[ii] = vals[ii] / sum;
                                IPDFThetaBiasH.InsertValues(bins[ii], vals[ii]);
                        }
                        // Make IPDFThetaBias = true
                        IPDFThetaBias = true;
                }
                // IPDF has been create so carry on
                G4double rndm = G4UniformRand();
                //      size_t weight_bin_no = IPDFThetaBiasH.FindValueBinLocation(rndm);
                size_t numberOfBin = IPDFThetaBiasH.GetVectorLength();
                G4int biasn1 = 0;
                G4int biasn2 = numberOfBin / 2;
                G4int biasn3 = numberOfBin - 1;
                while (biasn1 != biasn3 - 1) {
                        if (rndm > IPDFThetaBiasH(biasn2))
                                biasn1 = biasn2;
                        else
                                biasn3 = biasn2;
                        biasn2 = biasn1 + (biasn3 - biasn1 + 1) / 2;
                }
                bweights[3] = IPDFThetaBiasH(biasn2) - IPDFThetaBiasH(biasn2 - 1);
                G4double xaxisl = IPDFThetaBiasH.GetLowEdgeEnergy(size_t(biasn2 - 1));
                G4double xaxisu = IPDFThetaBiasH.GetLowEdgeEnergy(size_t(biasn2));
                G4double NatProb = xaxisu - xaxisl;
                bweights[3] = NatProb / bweights[3];
                if (verbosityLevel >= 1)
                        G4cout << "Theta bin weight " << bweights[3] << " " << rndm
                                        << G4endl;
                return (IPDFThetaBiasH.GetEnergy(rndm));
        }
}

G4double G4SPSRandomGenerator::GenRandPhi() {
        if (verbosityLevel >= 1)
                G4cout << "In GenRandPhi" << G4endl;
        if (PhiBias == false) {
                // Phi is not biased
                G4double rndm = G4UniformRand();
                return (rndm);
        } else {
                // Phi is biased
                if (IPDFPhiBias == false) {
                        // IPDF has not been created, so create it
                        G4double bins[1024], vals[1024], sum;
                        G4int ii;
                        G4int maxbin = G4int(PhiBiasH.GetVectorLength());
                        bins[0] = PhiBiasH.GetLowEdgeEnergy(size_t(0));
                        vals[0] = PhiBiasH(size_t(0));
                        sum = vals[0];
                        for (ii = 1; ii < maxbin; ii++) {
                                bins[ii] = PhiBiasH.GetLowEdgeEnergy(size_t(ii));
                                vals[ii] = PhiBiasH(size_t(ii)) + vals[ii - 1];
                                sum = sum + PhiBiasH(size_t(ii));
                        }

                        for (ii = 0; ii < maxbin; ii++) {
                                vals[ii] = vals[ii] / sum;
                                IPDFPhiBiasH.InsertValues(bins[ii], vals[ii]);
                        }
                        // Make IPDFPhiBias = true
                        IPDFPhiBias = true;
                }
                // IPDF has been create so carry on
                G4double rndm = G4UniformRand();
                //      size_t weight_bin_no = IPDFPhiBiasH.FindValueBinLocation(rndm);
                size_t numberOfBin = IPDFPhiBiasH.GetVectorLength();
                G4int biasn1 = 0;
                G4int biasn2 = numberOfBin / 2;
                G4int biasn3 = numberOfBin - 1;
                while (biasn1 != biasn3 - 1) {
                        if (rndm > IPDFPhiBiasH(biasn2))
                                biasn1 = biasn2;
                        else
                                biasn3 = biasn2;
                        biasn2 = biasn1 + (biasn3 - biasn1 + 1) / 2;
                }
                bweights[4] = IPDFPhiBiasH(biasn2) - IPDFPhiBiasH(biasn2 - 1);
                G4double xaxisl = IPDFPhiBiasH.GetLowEdgeEnergy(size_t(biasn2 - 1));
                G4double xaxisu = IPDFPhiBiasH.GetLowEdgeEnergy(size_t(biasn2));
                G4double NatProb = xaxisu - xaxisl;
                bweights[4] = NatProb / bweights[4];
                if (verbosityLevel >= 1)
                        G4cout << "Phi bin weight " << bweights[4] << " " << rndm << G4endl;
                return (IPDFPhiBiasH.GetEnergy(rndm));
        }
}

G4double G4SPSRandomGenerator::GenRandEnergy() {
        if (verbosityLevel >= 1)
                G4cout << "In GenRandEnergy" << G4endl;
        if (EnergyBias == false) {
                // Energy is not biased
                G4double rndm = G4UniformRand();
                return (rndm);
        } else {
                // ENERGY is biased
                if (IPDFEnergyBias == false) {
                        // IPDF has not been created, so create it
                        G4double bins[1024], vals[1024], sum;
                        G4int ii;
                        G4int maxbin = G4int(EnergyBiasH.GetVectorLength());
                        bins[0] = EnergyBiasH.GetLowEdgeEnergy(size_t(0));
                        vals[0] = EnergyBiasH(size_t(0));
                        sum = vals[0];
                        for (ii = 1; ii < maxbin; ii++) {
                                bins[ii] = EnergyBiasH.GetLowEdgeEnergy(size_t(ii));
                                vals[ii] = EnergyBiasH(size_t(ii)) + vals[ii - 1];
                                sum = sum + EnergyBiasH(size_t(ii));
                        }
                        IPDFEnergyBiasH = ZeroPhysVector;
                        for (ii = 0; ii < maxbin; ii++) {
                                vals[ii] = vals[ii] / sum;
                                IPDFEnergyBiasH.InsertValues(bins[ii], vals[ii]);
                        }
                        // Make IPDFEnergyBias = true
                        IPDFEnergyBias = true;
                }
                // IPDF has been create so carry on
                G4double rndm = G4UniformRand();
                //  size_t weight_bin_no = IPDFEnergyBiasH.FindValueBinLocation(rndm);
                size_t numberOfBin = IPDFEnergyBiasH.GetVectorLength();
                G4int biasn1 = 0;
                G4int biasn2 = numberOfBin / 2;
                G4int biasn3 = numberOfBin - 1;
                while (biasn1 != biasn3 - 1) {
                        if (rndm > IPDFEnergyBiasH(biasn2))
                                biasn1 = biasn2;
                        else
                                biasn3 = biasn2;
                        biasn2 = biasn1 + (biasn3 - biasn1 + 1) / 2;
                }
                bweights[5] = IPDFEnergyBiasH(biasn2) - IPDFEnergyBiasH(biasn2 - 1);
                G4double xaxisl = IPDFEnergyBiasH.GetLowEdgeEnergy(size_t(biasn2 - 1));
                G4double xaxisu = IPDFEnergyBiasH.GetLowEdgeEnergy(size_t(biasn2));
                G4double NatProb = xaxisu - xaxisl;
                bweights[5] = NatProb / bweights[5];
                if (verbosityLevel >= 1)
                        G4cout << "Energy bin weight " << bweights[5] << " " << rndm
                                        << G4endl;
                return (IPDFEnergyBiasH.GetEnergy(rndm));
        }
}

G4double G4SPSRandomGenerator::GenRandPosTheta() {
        if (verbosityLevel >= 1) {
                G4cout << "In GenRandPosTheta" << G4endl;
                G4cout << "Verbosity " << verbosityLevel << G4endl;
        }
        if (PosThetaBias == false) {
                // Theta is not biased
                G4double rndm = G4UniformRand();
                return (rndm);
        } else {
                // Theta is biased
                if (IPDFPosThetaBias == false) {
                        // IPDF has not been created, so create it
                        G4double bins[1024], vals[1024], sum;
                        G4int ii;
                        G4int maxbin = G4int(PosThetaBiasH.GetVectorLength());
                        bins[0] = PosThetaBiasH.GetLowEdgeEnergy(size_t(0));
                        vals[0] = PosThetaBiasH(size_t(0));
                        sum = vals[0];
                        for (ii = 1; ii < maxbin; ii++) {
                                bins[ii] = PosThetaBiasH.GetLowEdgeEnergy(size_t(ii));
                                vals[ii] = PosThetaBiasH(size_t(ii)) + vals[ii - 1];
                                sum = sum + PosThetaBiasH(size_t(ii));
                        }

                        for (ii = 0; ii < maxbin; ii++) {
                                vals[ii] = vals[ii] / sum;
                                IPDFPosThetaBiasH.InsertValues(bins[ii], vals[ii]);
                        }
                        // Make IPDFThetaBias = true
                        IPDFPosThetaBias = true;
                }
                // IPDF has been create so carry on
                G4double rndm = G4UniformRand();
                //      size_t weight_bin_no = IPDFThetaBiasH.FindValueBinLocation(rndm);
                size_t numberOfBin = IPDFPosThetaBiasH.GetVectorLength();
                G4int biasn1 = 0;
                G4int biasn2 = numberOfBin / 2;
                G4int biasn3 = numberOfBin - 1;
                while (biasn1 != biasn3 - 1) {
                        if (rndm > IPDFPosThetaBiasH(biasn2))
                                biasn1 = biasn2;
                        else
                                biasn3 = biasn2;
                        biasn2 = biasn1 + (biasn3 - biasn1 + 1) / 2;
                }
                bweights[6] = IPDFPosThetaBiasH(biasn2) - IPDFPosThetaBiasH(biasn2 - 1);
                G4double xaxisl =
                                IPDFPosThetaBiasH.GetLowEdgeEnergy(size_t(biasn2 - 1));
                G4double xaxisu = IPDFPosThetaBiasH.GetLowEdgeEnergy(size_t(biasn2));
                G4double NatProb = xaxisu - xaxisl;
                bweights[6] = NatProb / bweights[6];
                if (verbosityLevel >= 1)
                        G4cout << "PosTheta bin weight " << bweights[6] << " " << rndm
                                        << G4endl;
                return (IPDFPosThetaBiasH.GetEnergy(rndm));
        }
}

G4double G4SPSRandomGenerator::GenRandPosPhi() {
        if (verbosityLevel >= 1)
                G4cout << "In GenRandPosPhi" << G4endl;
        if (PosPhiBias == false) {
                // PosPhi is not biased
                G4double rndm = G4UniformRand();
                return (rndm);
        } else {
                // PosPhi is biased
                if (IPDFPosPhiBias == false) {
                        // IPDF has not been created, so create it
                        G4double bins[1024], vals[1024], sum;
                        G4int ii;
                        G4int maxbin = G4int(PosPhiBiasH.GetVectorLength());
                        bins[0] = PosPhiBiasH.GetLowEdgeEnergy(size_t(0));
                        vals[0] = PosPhiBiasH(size_t(0));
                        sum = vals[0];
                        for (ii = 1; ii < maxbin; ii++) {
                                bins[ii] = PosPhiBiasH.GetLowEdgeEnergy(size_t(ii));
                                vals[ii] = PosPhiBiasH(size_t(ii)) + vals[ii - 1];
                                sum = sum + PosPhiBiasH(size_t(ii));
                        }

                        for (ii = 0; ii < maxbin; ii++) {
                                vals[ii] = vals[ii] / sum;
                                IPDFPosPhiBiasH.InsertValues(bins[ii], vals[ii]);
                        }
                        // Make IPDFPosPhiBias = true
                        IPDFPosPhiBias = true;
                }
                // IPDF has been create so carry on
                G4double rndm = G4UniformRand();
                //      size_t weight_bin_no = IPDFPosPhiBiasH.FindValueBinLocation(rndm);
                size_t numberOfBin = IPDFPosPhiBiasH.GetVectorLength();
                G4int biasn1 = 0;
                G4int biasn2 = numberOfBin / 2;
                G4int biasn3 = numberOfBin - 1;
                while (biasn1 != biasn3 - 1) {
                        if (rndm > IPDFPosPhiBiasH(biasn2))
                                biasn1 = biasn2;
                        else
                                biasn3 = biasn2;
                        biasn2 = biasn1 + (biasn3 - biasn1 + 1) / 2;
                }
                bweights[7] = IPDFPosPhiBiasH(biasn2) - IPDFPosPhiBiasH(biasn2 - 1);
                G4double xaxisl = IPDFPosPhiBiasH.GetLowEdgeEnergy(size_t(biasn2 - 1));
                G4double xaxisu = IPDFPosPhiBiasH.GetLowEdgeEnergy(size_t(biasn2));
                G4double NatProb = xaxisu - xaxisl;
                bweights[7] = NatProb / bweights[7];
                if (verbosityLevel >= 1)
                        G4cout << "PosPhi bin weight " << bweights[7] << " " << rndm
                                        << G4endl;
                return (IPDFPosPhiBiasH.GetEnergy(rndm));
        }
}

---