OpenMS  2.8.0
SplineBisection.h
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31 // $Maintainer: Hannes Roest $
32 // $Authors: Hannes Roest $
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34 
35 #pragma once
36 
37 #include <OpenMS/config.h>
38 
39 #include <limits>
40 #include <cmath>
41 
42 namespace OpenMS
43 {
50  namespace Math
51  {
52 
53  template <class T>
54  void spline_bisection(const T & peak_spline,
55  double const left_neighbor_mz,
56  double const right_neighbor_mz,
57  double & max_peak_mz,
58  double & max_peak_int,
59  double const threshold = 1e-6)
60  {
61  // calculate maximum by evaluating the spline's 1st derivative
62  // (bisection method)
63  double lefthand = left_neighbor_mz;
64  double righthand = right_neighbor_mz;
65 
66  bool lefthand_sign = true;
67  double eps = std::numeric_limits<double>::epsilon();
68 
69  // bisection
70  do
71  {
72  double mid = (lefthand + righthand) / 2.0;
73  double midpoint_deriv_val = peak_spline.derivative(mid);
74 
75  // if deriv nearly zero then maximum already found
76  if (!(std::fabs(midpoint_deriv_val) > eps))
77  {
78  break;
79  }
80 
81  bool midpoint_sign = (midpoint_deriv_val < 0.0) ? false : true;
82 
83  if (lefthand_sign ^ midpoint_sign)
84  {
85  righthand = mid;
86  }
87  else
88  {
89  lefthand = mid;
90  }
91  }
92  while (righthand - lefthand > threshold);
93 
94  max_peak_mz = (lefthand + righthand) / 2;
95  max_peak_int = peak_spline.eval(max_peak_mz);
96  }
97 
98  }
99 }
void spline_bisection(const T &peak_spline, double const left_neighbor_mz, double const right_neighbor_mz, double &max_peak_mz, double &max_peak_int, double const threshold=1e-6)
Definition: SplineBisection.h:54
Main OpenMS namespace.
Definition: FeatureDeconvolution.h:47