G4Exp.hh File Reference

#include "G4Types.hh"
#include "G4IEEE754.hh"
#include <cstdint>
#include <limits>

Go to the source code of this file.

Namespaces
namespace	G4ExpConsts

Functions
G4double	G4ExpConsts::fpfloor (const G4double x)
G4float	G4ExpConsts::fpfloor (const G4float x)
G4double	G4Exp (G4double initial_x)
	Exponential Function double precision.
G4float	G4Expf (G4float initial_x)
	Exponential Function single precision.

Variables
const G4double	G4ExpConsts::EXP_LIMIT = 708
const G4double	G4ExpConsts::PX1exp = 1.26177193074810590878E-4
const G4double	G4ExpConsts::PX2exp = 3.02994407707441961300E-2
const G4double	G4ExpConsts::PX3exp = 9.99999999999999999910E-1
const G4double	G4ExpConsts::QX1exp = 3.00198505138664455042E-6
const G4double	G4ExpConsts::QX2exp = 2.52448340349684104192E-3
const G4double	G4ExpConsts::QX3exp = 2.27265548208155028766E-1
const G4double	G4ExpConsts::QX4exp = 2.00000000000000000009E0
const G4double	G4ExpConsts::LOG2E = 1.4426950408889634073599
const G4float	G4ExpConsts::MAXLOGF = 88.72283905206835f
const G4float	G4ExpConsts::MINLOGF = -88.f
const G4float	G4ExpConsts::C1F = 0.693359375f
const G4float	G4ExpConsts::C2F = -2.12194440e-4f
const G4float	G4ExpConsts::PX1expf = 1.9875691500E-4f
const G4float	G4ExpConsts::PX2expf = 1.3981999507E-3f
const G4float	G4ExpConsts::PX3expf = 8.3334519073E-3f
const G4float	G4ExpConsts::PX4expf = 4.1665795894E-2f
const G4float	G4ExpConsts::PX5expf = 1.6666665459E-1f
const G4float	G4ExpConsts::PX6expf = 5.0000001201E-1f
const G4float	G4ExpConsts::LOG2EF = 1.44269504088896341f

Function Documentation

G4Exp()

G4double G4Exp ( G4double initial_x )

inline

Exponential Function double precision.

Definition at line 132 of file G4Exp.hh.

{
  G4double x  = initial_x;
  G4double px = G4ExpConsts::fpfloor(G4ExpConsts::LOG2E * x + 0.5);
 
  const int32_t n = int32_t(px);
 
  x -= px * 6.93145751953125E-1;
  x -= px * 1.42860682030941723212E-6;
 
  const G4double xx = x * x;
 
  // px = x * P(x**2).
  px = G4ExpConsts::PX1exp;
  px *= xx;
  px += G4ExpConsts::PX2exp;
  px *= xx;
  px += G4ExpConsts::PX3exp;
  px *= x;
 
  // Evaluate Q(x**2).
  G4double qx = G4ExpConsts::QX1exp;
  qx *= xx;
  qx += G4ExpConsts::QX2exp;
  qx *= xx;
  qx += G4ExpConsts::QX3exp;
  qx *= xx;
  qx += G4ExpConsts::QX4exp;
 
  // e**x = 1 + 2x P(x**2)/( Q(x**2) - P(x**2) )
  x = px / (qx - px);
  x = 1.0 + 2.0 * x;
 
  // Build 2^n in double.
  x *= G4IEEE754::uint642dp((((uint64_t) n) + 1023) << 52);
 
  if(initial_x > G4ExpConsts::EXP_LIMIT)
    x = std::numeric_limits<G4double>::infinity();
  if(initial_x < -G4ExpConsts::EXP_LIMIT)
    x = 0.;
 
  return x;
}

Referenced by G4DynamicParticleMSC::AlongStepDoIt(), G4NuclNuclDiffuseElastic::AmplitudeGG(), G4NuclNuclDiffuseElastic::AmplitudeGla(), G4Nucleus::AnnihilationEvaporationEffects(), G4WilsonAbrasionModel::ApplyYourself(), G4DNAMolecularReactionData::ArrehniusParam(), G4EmCorrections::BarkasCorrection(), G4WilsonAblationModel::BreakItUp(), G4LightIonQMDMeanField::Cal2BodyQuantities(), G4LightIonQMDMeanField::Cal2BodyQuantities(), G4QMDMeanField::Cal2BodyQuantities(), G4QMDMeanField::Cal2BodyQuantities(), G4StatMFMacroBiNucleon::CalcMeanMultiplicity(), G4StatMFMacroMultiNucleon::CalcMeanMultiplicity(), G4StatMFMacroNucleon::CalcMeanMultiplicity(), G4StatMFMacroTetraNucleon::CalcMeanMultiplicity(), G4StatMFMacroTriNucleon::CalcMeanMultiplicity(), G4StatMFMicroPartition::CalcPartitionProbability(), G4LinLogInterpolation::Calculate(), G4LinLogInterpolation::Calculate(), G4ecpssrBaseKxsModel::CalculateCrossSection(), G4ecpssrBaseLixsModel::CalculateL1CrossSection(), G4OrlicLiXsModel::CalculateL1CrossSection(), G4ecpssrBaseLixsModel::CalculateL2CrossSection(), G4OrlicLiXsModel::CalculateL2CrossSection(), G4ecpssrBaseLixsModel::CalculateL3CrossSection(), G4OrlicLiXsModel::CalculateL3CrossSection(), G4PreCompoundTransitions::CalculateProbability(), G4PreCompoundTransitionsInt::CalculateProbability(), G4Reggeons::CalculateXs(), G4LightIonQMDCollision::CalFinalStateOfTheBinaryCollisionJQMD(), G4QMDCollision::CalFinalStateOfTheBinaryCollisionJQMD(), G4Reggeons::Chi_pomeron(), G4Reggeons::Chi_reggeon(), G4NucleiModel::choosePointAlongTraj(), G4Nucleus::Cinema(), G4Clebsch::ClebschGordanCoeff(), G4KalbachCrossSection::ComputeCrossSection(), G4GammaConversionToMuons::ComputeCrossSectionPerAtom(), G4KleinNishinaCompton::ComputeCrossSectionPerAtom(), G4KleinNishinaModel::ComputeCrossSectionPerAtom(), G4PenelopeGammaConversionModel::ComputeCrossSectionPerAtom(), G4PenelopePhotoElectricModel::ComputeCrossSectionPerAtom(), G4PenelopeRayleighModel::ComputeCrossSectionPerAtom(), G4PenelopeRayleighModelMI::ComputeCrossSectionPerAtom(), G4AnnihiToMuPair::ComputeCrossSectionPerElectron(), G4MuBetheBlochModel::ComputeCrossSectionPerElectron(), G4eDPWAElasticDCS::ComputeCSPerAtom(), G4KokoulinMuonNuclearXS::ComputeDDMicroscopicCrossSection(), G4MuBetheBlochModel::ComputeDEDXPerVolume(), G4MuonToMuonPairProductionModel::ComputeDMicroscopicCrossSection(), G4MuPairProductionModel::ComputeDMicroscopicCrossSection(), G4RiGeMuPairProductionModel::ComputeDMicroscopicCrossSection(), G4LivermoreBremsstrahlungModel::ComputeDXSectionPerAtom(), G4PhotoNuclearCrossSection::ComputeElementXSection(), G4UrbanAdjointMscModel::ComputeGeomPathLength(), G4UrbanMscModel::ComputeGeomPathLength(), G4WentzelVIModel::ComputeGeomPathLength(), G4MuBremsstrahlungModel::ComputeMicroscopicCrossSection(), G4MuPairProductionModel::ComputeMicroscopicCrossSection(), G4RiGeMuPairProductionModel::ComputeMicroscopicCrossSection(), G4EvaporationProbability::ComputeProbability(), G4UrbanAdjointMscModel::ComputeTheta0(), G4UrbanMscModel::ComputeTheta0(), G4UrbanAdjointMscModel::ComputeTrueStepLength(), G4UrbanMscModel::ComputeTrueStepLength(), G4RToEConvForElectron::ComputeValue(), G4RToEConvForGamma::ComputeValue(), G4RToEConvForPositron::ComputeValue(), G4MuPairProductionModel::ComputMuPairLoss(), G4RiGeMuPairProductionModel::ComputMuPairLoss(), G4DiffractiveExcitation::CreateStrings(), G4LowEXsection::CrossSection(), G4XpimNTotal::CrossSection(), G4XpipNTotal::CrossSection(), G4DNABornIonisationModel1::CrossSectionPerVolume(), G4DNABornIonisationModel2::CrossSectionPerVolume(), G4DNABornIonisationModel::CrossSectionPerVolume(), G4MuonToMuonPairProductionModel::DataCorrupted(), G4MuPairProductionModel::DataCorrupted(), G4RiGeMuPairProductionModel::DataCorrupted(), G4EquilibriumEvaporator::deExcite(), G4FissionParameters::DefineParameters(), G4EmCorrections::DensityCorrection(), G4AtimaFluctuations::Dispersion(), G4PenelopeRayleighModel::DumpFormFactorTable(), G4PenelopeRayleighModelMI::DumpFormFactorTable(), G4ionEffectiveCharge::EffectiveCharge(), G4FissionProbability::EmissionProbability(), G4PhysicsFreeVector::EnableLogBinSearch(), epsilon(), G4LegendrePolynomial::EvalAssocLegendrePoly(), G4Nucleus::EvaporationEffects(), G4Pow::expA(), G4ecpssrBaseKxsModel::ExpIntFunction(), G4ecpssrBaseLixsModel::ExpIntFunction(), G4QuasiElRatios::FetchElTot(), G4HadXSHelper::FillPeaksStructure(), G4NucleiModel::fillZoneRadii(), G4EmUtility::FindCrossSectionMax(), G4HadXSHelper::FindCrossSectionMax(), G4DNASmoluchowskiReactionModel::FindReaction(), G4JTPolynomialSolver::FindRoots(), G4AtimaEnergyLossModel::G4AtimaEnergyLossModel(), G4AtimaFluctuations::G4AtimaFluctuations(), G4InuclSpecialFunctions::G4cbrt(), G4ElasticHadrNucleusHE::G4ElasticHadrNucleusHE(), G4LightIonQMDGroundStateNucleus::G4LightIonQMDGroundStateNucleus(), G4MuBremsstrahlungModel::G4MuBremsstrahlungModel(), G4MuPairProductionModel::G4MuPairProductionModel(), G4ParticleHPFissionSpectrum::G4ParticleHPFissionSpectrum(), G4ParticleHPMadlandNixSpectrum::G4ParticleHPMadlandNixSpectrum(), G4ParticleHPSimpleEvapSpectrum::G4ParticleHPSimpleEvapSpectrum(), G4ParticleHPWattSpectrum::G4ParticleHPWattSpectrum(), G4PhysicsLogVector::G4PhysicsLogVector(), G4Poisson(), G4QMDGroundStateNucleus::G4QMDGroundStateNucleus(), G4RiGeMuPairProductionModel::G4RiGeMuPairProductionModel(), G4XNNElasticLowE::G4XNNElasticLowE(), G4XnpElasticLowE::G4XnpElasticLowE(), G4XnpTotalLowE::G4XnpTotalLowE(), G4FTFParameters::GammaElastic(), G4IntraNucleiCascader::generateCascade(), G4eeToHadronsModel::GenerateCMPhoton(), G4FissionStore::generateConfiguration(), G4CascadeFinalStateAlgorithm::GenerateCosTheta(), G4NucleiModel::generateInteractionLength(), G4AtomicFormFactor::Get(), G4ParticleHPInterpolator::GetBinIntegral(), G4DNASmoluchowskiDiffusion::GetCumulativeProbability(), G4IonisParamMat::GetDensityCorrection(), G4DNASmoluchowskiDiffusion::GetDensityProbability(), G4NuclearFermiDensity::GetDeriv(), G4DiffuseElastic::GetDiffElasticProb(), G4NuclNuclDiffuseElastic::GetDiffElasticProb(), G4DiffuseElastic::GetDiffElasticSumProb(), G4NuclNuclDiffuseElastic::GetDiffElasticSumProb(), G4DiffuseElastic::GetDiffElasticSumProbA(), G4DiffuseElasticV2::GetDiffElasticSumProbA(), G4NuclNuclDiffuseElastic::GetDiffElasticSumProbA(), G4DNASmoluchowskiDiffusion::GetDifferential(), G4PhotonEvaporation::GetEmissionProbability(), G4ElectroNuclearCrossSection::GetEquivalentPhotonEnergy(), G4ElectroNuclearCrossSection::GetEquivalentPhotonQ2(), G4NuclNuclDiffuseElastic::GetErfComp(), G4ChipsAntiBaryonElasticXS::GetExchangeT(), G4ChipsHyperonElasticXS::GetExchangeT(), G4ChipsPionMinusElasticXS::GetExchangeT(), G4ChipsPionPlusElasticXS::GetExchangeT(), G4NuclNuclDiffuseElastic::GetExpCos(), G4hhElastic::GetExpRatioF123(), G4NuclNuclDiffuseElastic::GetExpSin(), G4PenelopeCrossSection::GetHardCrossSection(), 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G4eBremsstrahlungRelModel::SampleSecondaries(), G4KleinNishinaCompton::SampleSecondaries(), G4KleinNishinaModel::SampleSecondaries(), G4LivermoreBremsstrahlungModel::SampleSecondaries(), G4LivermoreComptonModel::SampleSecondaries(), G4LivermoreNuclearGammaConversionModel::SampleSecondaries(), G4LivermorePolarizedComptonModel::SampleSecondaries(), G4LivermorePolarizedGammaConversionModel::SampleSecondaries(), G4LowEPComptonModel::SampleSecondaries(), G4LowEPPolarizedComptonModel::SampleSecondaries(), G4MuBremsstrahlungModel::SampleSecondaries(), G4MuonToMuonPairProductionModel::SampleSecondaries(), G4MuPairProductionModel::SampleSecondaries(), G4PenelopeComptonModel::SampleSecondaries(), G4PolarizedComptonModel::SampleSecondaries(), G4RiGeMuPairProductionModel::SampleSecondaries(), G4WentzelOKandVIxSection::SampleSingleScattering(), G4ChargeExchange::SampleT(), G4ChargeExchangeXS::SampleTforPion(), G4GoudsmitSaundersonTable::Sampling(), G4IonCoulombCrossSection::SetupTarget(), 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G4Expf()

G4float G4Expf ( G4float initial_x )

inline

Exponential Function single precision.

Definition at line 179 of file G4Exp.hh.

{
  G4float x = initial_x;
 
  G4float z =
    G4ExpConsts::fpfloor(G4ExpConsts::LOG2EF * x +
                         0.5f); /* std::floor() truncates toward -infinity. */
 
  x -= z * G4ExpConsts::C1F;
  x -= z * G4ExpConsts::C2F;
  const int32_t n = int32_t(z);
 
  const G4float x2 = x * x;
 
  z = x * G4ExpConsts::PX1expf;
  z += G4ExpConsts::PX2expf;
  z *= x;
  z += G4ExpConsts::PX3expf;
  z *= x;
  z += G4ExpConsts::PX4expf;
  z *= x;
  z += G4ExpConsts::PX5expf;
  z *= x;
  z += G4ExpConsts::PX6expf;
  z *= x2;
  z += x + 1.0f;
 
  /* multiply by power of 2 */
  z *= G4IEEE754::uint322sp((n + 0x7f) << 23);
 
  if(initial_x > G4ExpConsts::MAXLOGF)
    z = std::numeric_limits<G4float>::infinity();
  if(initial_x < G4ExpConsts::MINLOGF)
    z = 0.f;
 
  return z;
}