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G4LinInterpolation.cc
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25 //
26 //
27 //
28 // Author: Maria Grazia Pia (Maria.Grazia.Pia@cern.ch)
29 //
30 // History:
31 // -----------
32 // 31 Jul 2001 MGP Created
33 // 14 JUn 2009 NAK New Calculation method implemented to which logarithmic values
34 // from the G4EMLOW dataset are loaded directly to enhance performance
35 //
36 // -------------------------------------------------------------------
37 
38 #include "G4LinInterpolation.hh"
39 
40 // Constructor
41 
43 { }
44 
45 // Destructor
46 
48 { }
49 
50 
52 { return new G4LinInterpolation; }
53 
55  const G4DataVector& points,
56  const G4DataVector& data) const
57 {
58  //G4cout << "G4LinInterpolation is performed (2 arguments)" << G4endl;
59  G4int nBins = data.size() - 1;
60  G4double value = 0.;
61  if (x < points[0])
62  {
63  value = 0.;
64  }
65  else if (bin < nBins)
66  {
67  G4double e1 = points[bin];
68  G4double e2 = points[bin+1];
69  G4double d1 = data[bin];
70  G4double d2 = data[bin+1];
71  value = d1 + (d2 - d1)*(x - e1)/(e2 - e1);
72  }
73  else
74  {
75  value = data[nBins];
76  }
77  return value;
78 }
79 
80 
81 //Nicolas A. Karakatsanis: New Calculation method implemented to which logarithmic values
82 // from the G4EMLOW dataset are loaded directly to enhance performance
83 
85  const G4DataVector& points,
86  const G4DataVector& data,
87  const G4DataVector& log_points,
88  const G4DataVector& log_data) const
89 {
90 //Linear Interpolation is performed on loagarithmic data set
91 //Equivalent to log-log interpolation on non-loagarithmic data set
92  //G4cout << "G4LinInterpolation is performed - (4 arguments)" << G4endl;
93  G4int nBins = data.size() - 1;
94  G4double value = 0.;
95  G4double log_x = std::log10(x);
96  if (x < points[0])
97  {
98  value = 0.;
99  }
100  else if (bin < nBins)
101  {
102  G4double log_e1 = log_points[bin];
103  G4double log_e2 = log_points[bin+1];
104  G4double log_d1 = log_data[bin];
105  G4double log_d2 = log_data[bin+1];
106 
107 // Values e1, e2, d1 and d2 are the log values of the corresponding
108 // original energy and data values. Simple linear interpolation performed
109 // on loagarithmic data should be equivalent to log-log interpolation
110  value = log_d1 + (log_d2 - log_d1)*(log_x - log_e1)/(log_e2 - log_e1);
111 
112 // Delogarithmize to obtain interpolated value
113  value = std::pow(10.,value);
114  }
115  else
116  {
117  value = data[nBins];
118  }
119  return value;
120 }