Geant4  10.01.p01
G4LinInterpolation.cc
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27 // $Id: G4LinInterpolation.cc 66241 2012-12-13 18:34:42Z gunter $
28 //
29 // Author: Maria Grazia Pia (Maria.Grazia.Pia@cern.ch)
30 //
31 // History:
32 // -----------
33 // 31 Jul 2001 MGP Created
34 // 14 JUn 2009 NAK New Calculation method implemented to which logarithmic values
35 // from the G4EMLOW dataset are loaded directly to enhance performance
36 //
37 // -------------------------------------------------------------------
38 
39 #include "G4LinInterpolation.hh"
40 
41 // Constructor
42 
44 { }
45 
46 // Destructor
47 
49 { }
50 
51 
53 { return new G4LinInterpolation; }
54 
56  const G4DataVector& points,
57  const G4DataVector& data) const
58 {
59  //G4cout << "G4LinInterpolation is performed (2 arguments)" << G4endl;
60  G4int nBins = data.size() - 1;
61  G4double value = 0.;
62  if (x < points[0])
63  {
64  value = 0.;
65  }
66  else if (bin < nBins)
67  {
68  G4double e1 = points[bin];
69  G4double e2 = points[bin+1];
70  G4double d1 = data[bin];
71  G4double d2 = data[bin+1];
72  value = d1 + (d2 - d1)*(x - e1)/(e2 - e1);
73  }
74  else
75  {
76  value = data[nBins];
77  }
78  return value;
79 }
80 
81 
82 //Nicolas A. Karakatsanis: New Calculation method implemented to which logarithmic values
83 // from the G4EMLOW dataset are loaded directly to enhance performance
84 
86  const G4DataVector& points,
87  const G4DataVector& data,
88  const G4DataVector& log_points,
89  const G4DataVector& log_data) const
90 {
91 //Linear Interpolation is performed on loagarithmic data set
92 //Equivalent to log-log interpolation on non-loagarithmic data set
93  //G4cout << "G4LinInterpolation is performed - (4 arguments)" << G4endl;
94  G4int nBins = data.size() - 1;
95  G4double value = 0.;
96  G4double log_x = std::log10(x);
97  if (x < points[0])
98  {
99  value = 0.;
100  }
101  else if (bin < nBins)
102  {
103  G4double log_e1 = log_points[bin];
104  G4double log_e2 = log_points[bin+1];
105  G4double log_d1 = log_data[bin];
106  G4double log_d2 = log_data[bin+1];
107 
108 // Values e1, e2, d1 and d2 are the log values of the corresponding
109 // original energy and data values. Simple linear interpolation performed
110 // on loagarithmic data should be equivalent to log-log interpolation
111  value = log_d1 + (log_d2 - log_d1)*(log_x - log_e1)/(log_e2 - log_e1);
112 
113 // Delogarithmize to obtain interpolated value
114  value = std::pow(10.,value);
115  }
116  else
117  {
118  value = data[nBins];
119  }
120  return value;
121 }
static const G4double d1
G4double Calculate(G4double point, G4int bin, const G4DataVector &energies, const G4DataVector &data) const
static const G4double e2
int G4int
Definition: G4Types.hh:78
static const G4double e1
G4VDataSetAlgorithm * Clone() const
double G4double
Definition: G4Types.hh:76
static const G4double d2