Import Geant4 10.0.0 source tree

source/processes/biasing/generic/src/G4InteractionLawPhysical.cc

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+//
+// ********************************************************************
+// * License and Disclaimer                                           *
+// *                                                                  *
+// * The  Geant4 software  is  copyright of the Copyright Holders  of *
+// * the Geant4 Collaboration.  It is provided  under  the terms  and *
+// * conditions of the Geant4 Software License,  included in the file *
+// * LICENSE and available at  http://cern.ch/geant4/license .  These *
+// * include a list of copyright holders.                             *
+// *                                                                  *
+// * Neither the authors of this software system, nor their employing *
+// * institutes,nor the agencies providing financial support for this *
+// * work  make  any representation or  warranty, express or implied, *
+// * regarding  this  software system or assume any liability for its *
+// * use.  Please see the license in the file  LICENSE  and URL above *
+// * for the full disclaimer and the limitation of liability.         *
+// *                                                                  *
+// * This  code  implementation is the result of  the  scientific and *
+// * technical work of the GEANT4 collaboration.                      *
+// * By using,  copying,  modifying or  distributing the software (or *
+// * any work based  on the software)  you  agree  to acknowledge its *
+// * use  in  resulting  scientific  publications,  and indicate your *
+// * acceptance of all terms of the Geant4 Software license.          *
+// ********************************************************************
+//
+#include "G4InteractionLawPhysical.hh"
+#include "Randomize.hh"
+
+G4InteractionLawPhysical::G4InteractionLawPhysical(G4String name)
+  : G4VBiasingInteractionLaw(name),
+    fCrossSection(0.0),
+    fCrossSectionDefined(false),
+    fNumberOfInteractionLength(-1.0)
+{}
+
+G4InteractionLawPhysical::~G4InteractionLawPhysical()
+{}
+
+void G4InteractionLawPhysical::SetPhysicalCrossSection(G4double crossSection)
+{
+  if (crossSection < 0.0)
+    {
+      G4Exception("G4InteractionLawPhysical::SetPhysicalCrossSection(..)",
+		  "BIAS.GEN.14",
+		  JustWarning,
+		  "Cross-section value passed is negative. It is set to zero !");
+      crossSection = 0.0;
+    }
+  fCrossSectionDefined = true;
+  fCrossSection        = crossSection;
+}
+
+G4double G4InteractionLawPhysical::ComputeEffectiveCrossSectionAt(G4double) const
+{
+  if (!fCrossSectionDefined) G4Exception("G4InteractionLawPhysical::ComputeEffectiveCrossSection(..)",
+					 "BIAS.GEN.15",
+					 JustWarning,
+					 "Cross-section value requested, but has not been defined yet. Assumes 0 !");
+  return fCrossSection;
+}
+
+G4double G4InteractionLawPhysical::ComputeNonInteractionProbabilityAt(G4double stepLength) const
+{
+  if (!fCrossSectionDefined) G4Exception("G4InteractionLawPhysical::ComputeNonInteractionProbability(..)",
+					 "BIAS.GEN.16",
+					 JustWarning,
+					 "Non interaction probabitlity value requested, but cross section has not been defined yet. Assumes it to be 0 !");
+  // -- allows zero cross-section case, by convention:
+  if ( fCrossSection == 0.0 ) return 1.0;
+  else return std::exp(-fCrossSection*stepLength);
+}
+
+G4double G4InteractionLawPhysical::SampleInteractionLength()
+{
+  if ( !fCrossSectionDefined || fCrossSection < 0.0 )  G4Exception("G4InteractionLawPhysical::Sample(..)",
+								   "BIAS.GEN.17",
+								   FatalException,
+								   "Trying to sample while cross-section is not defined or < 0 !");
+  if ( fCrossSection == 0.0 ) return DBL_MAX;
+
+  fNumberOfInteractionLength =  -std::log( G4UniformRand() );
+  return fNumberOfInteractionLength/fCrossSection;
+}
+
+
+G4double G4InteractionLawPhysical::UpdateInteractionLengthForStep(G4double       truePathLength)
+{
+  fNumberOfInteractionLength -= truePathLength*fCrossSection;
+  if ( fNumberOfInteractionLength < 0 ) 
+    {
+      G4ExceptionDescription ed;
+      ed << " Negative number of interaction length for `" << GetName() << "' " << fNumberOfInteractionLength << ", set it to zero !" << G4endl; 
+      G4Exception("G4InteractionLawPhysical::UpdateInteractionLengthForStep(...)",
+		  "BIAS.GEN.13",
+		  JustWarning,
+		  ed);
+      fNumberOfInteractionLength = 0.;
+    }
+  return  fNumberOfInteractionLength;
+}