ROOT   6.08/07 Reference Guide
Interpolator.h
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1 // @(#)root/mathmore:$Id$
2 // Authors: L. Moneta, A. Zsenei 08/2005
3
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24
25 // Header file for class Interpolator
26 //
27 // Created by: moneta at Fri Nov 26 15:00:25 2004
28 //
29 // Last update: Fri Nov 26 15:00:25 2004
30 //
31 #ifndef ROOT_Math_Interpolator
32 #define ROOT_Math_Interpolator
33
35
36 #include <vector>
37 #include <string>
38
39 /**
40 @defgroup Interpolation Interpolation Classes
41
42 Classes for interpolation of points
43
44 @ingroup NumAlgo
45 */
46
47
48 namespace ROOT {
49 namespace Math {
50
51
52  class GSLInterpolator;
53
54 //_____________________________________________________________________________________
55  /**
56  Class for performing function interpolation of points.
57  The class is instantiated with an interpolation methods, passed as an enumeration in the constructor.
58  See Interpolation::Type for the available interpolation algorithms, which are implemented using GSL.
60  The class provides additional methods for computing derivatives and integrals of interpolating functions.
61
62  This class does not support copying.
63  @ingroup Interpolation
64  */
65
66 class Interpolator {
67
68 public:
69
70  /**
71  Constructs an interpolator class from number of data points and with Interpolation::Type type.
72  The data can be set later on with the SetData method.
73  In case the data size is not known, better using the default of zero or the next constructor later on.
74  The default interpolation type is Cubic spline
75  */
77
78  /**
79  Constructs an interpolator class from vector of data points \f$(x_i, y_i )\f$ and with Interpolation::Type type.
80  The method will compute a continuous interpolating function \f$y(x) \f$ such that \f$y_i = y ( x_i )\f$.
81  The default interpolation type is Cubic spline
82  */
83  Interpolator(const std::vector<double> & x, const std::vector<double> & y, Interpolation::Type type = Interpolation::kCSPLINE);
84
85  virtual ~Interpolator();
86
87 private:
88  // usually copying is non trivial, so we make this unaccessible
89  Interpolator(const Interpolator &);
91
92 public:
93
94  /**
95  Set the data vector ( x[] and y[] )
96  To be efficient, the size of the data must be the same of the value used in the constructor (ndata)
97  If this is not the case a new re-initialization is performed with the new data size
98  */
99  bool SetData(const std::vector<double> & x, const std::vector<double> & y);
100
101  /**
102  Set the data vector ( x[] and y[] )
103  To be efficient, the size of the data must be the same of the value used when constructing the class (ndata)
104  If this is not the case a new re-initialization is performed with the new data size.
105  */
106  bool SetData(unsigned int ndata, const double * x, const double * y);
107
108  /**
109  Return the interpolated value at point x
110  */
111  double Eval( double x ) const;
112
113  /**
114  Return the derivative of the interpolated function at point x
115  */
116  double Deriv( double x ) const;
117
118  /**
119  Return the second derivative of the interpolated function at point x
120  */
121  double Deriv2( double x ) const;
122
123  /**
124  Return the Integral of the interpolated function over the range [a,b]
125  */
126  double Integ( double a, double b) const;
127
128  /**
129  Return the type of interpolation method
130  */
131  std::string Type() const;
132  std::string TypeGet() const;
133
134 protected:
135
136
137 private:
138
139  GSLInterpolator * fInterp; // pointer to GSL interpolator class
140
141 };
142
143 } // namespace Math
144 } // namespace ROOT
145
146
147 #endif /* ROOT_Math_Interpolator */
const int ndata
double Integ(double a, double b) const
Return the Integral of the interpolated function over the range [a,b].
bool SetData(const std::vector< double > &x, const std::vector< double > &y)
Set the data vector ( x[] and y[] ) To be efficient, the size of the data must be the same of the val...
GSLInterpolator * fInterp
Definition: Interpolator.h:139
This namespace contains pre-defined functions to be used in conjuction with TExecutor::Map and TExecu...
Definition: StringConv.hxx:21
double Deriv(double x) const
Return the derivative of the interpolated function at point x.
Interpolator & operator=(const Interpolator &)
Class for performing function interpolation of points.
Definition: Interpolator.h:66
TArc * a
Definition: textangle.C:12
Double_t x[n]
Definition: legend1.C:17
std::string Type() const
Return the type of interpolation method.
Interpolation class based on GSL interpolation functions.
int type
Definition: TGX11.cxx:120
Type
Enumeration defining the types of interpolation methods availables.
Double_t y[n]
Definition: legend1.C:17
Namespace for new Math classes and functions.
double Deriv2(double x) const
Return the second derivative of the interpolated function at point x.
you should not use this method at all Int_t Int_t Double_t Double_t Double_t Int_t Double_t Double_t Double_t Double_t b
Definition: TRolke.cxx:630
double Eval(double x) const
Return the interpolated value at point x.
Interpolator(unsigned int ndata=0, Interpolation::Type type=Interpolation::kCSPLINE)
Constructs an interpolator class from number of data points and with Interpolation::Type type...
std::string TypeGet() const