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Reference Guide
MinimizerVariableTransformation.cxx
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1// @(#)root/mathmore:$Id$
2// Author: L. Moneta 2009
3
4// Implementation file for all the MinimizerVariableTransormation's
5// (implementations taken from minuit2 classes)
6
7
9#include <cmath>
10#include <limits>
11
12namespace ROOT {
13
14 namespace Math {
15
16// implementations for the class SinVariableTransformation
17
18double SinVariableTransformation::Int2ext(double value, double lower, double upper) const {
19 // transformation from internal (unlimited) to external values (limited by lower/upper )
20 return lower + 0.5*(upper - lower)*(std::sin(value) + 1.);
21}
22
23double SinVariableTransformation::Ext2int(double value, double lower, double upper) const {
24 // transformation from external (limited by lower/upper ) to internal (unlimited) values given the lower/upper limits
25
26 double piby2 = 2.*std::atan(1.);
27 static const double eps = std::numeric_limits<double>::epsilon();
28 double distnn = 8.*std::sqrt(eps);
29 double vlimhi = piby2 - distnn;
30 double vlimlo = -piby2 + distnn;
31
32 double yy = 2.*(value - lower)/(upper - lower) - 1.;
33 double yy2 = yy*yy;
34 if(yy2 > (1. - 8 * eps) ) {
35 if(yy < 0.) {
36 // lower limit
37 // std::cout<<"SinVariableTransformation warning: is at its lower allowed limit. "<<value<<std::endl;
38 return vlimlo;
39 } else {
40 // upper limit
41 // std::cout<<"SinVariableTransformation warning: is at its upper allowed limit."<<std::endl;
42 return vlimhi;
43 }
44
45 } else {
46 return std::asin(yy);
47 }
48}
49
50double SinVariableTransformation::DInt2Ext(double value, double lower, double upper) const {
51 // return the derivative of the internal to external transformation (Int2Ext) : d Int2Ext / d Int
52 return 0.5*((upper - lower)*std::cos(value));
53}
54
55// sqrt up
56// implementations for the class SqrtUpVariableTransformation
57
58
59 double SqrtLowVariableTransformation::Int2ext(double value, double lower, double) const {
60 /// internal to external transformation
61 double val = lower - 1. + std::sqrt( value*value + 1.);
62 return val;
63}
64
65
66double SqrtLowVariableTransformation::Ext2int(double value, double lower, double ) const {
67 // external to internal transformation
68 double yy = value - lower + 1.;
69 double yy2 = yy*yy;
70 if (yy2 < 1. )
71 return 0;
72 else
73 return std::sqrt( yy2 -1);
74}
75
76double SqrtLowVariableTransformation::DInt2Ext(double value, double, double) const {
77 // derivative of internal to external transofrmation : d (Int2Ext) / d Int
78 double val = value/( std::sqrt( value*value + 1.) );
79 return val;
80}
81
82// sqrt up
83// implementations for the class SqrtUpVariableTransformation
84
85double SqrtUpVariableTransformation::Int2ext(double value, double upper, double) const {
86 // internal to external transformation
87 double val = upper + 1. - std::sqrt( value*value + 1.);
88 return val;
89}
90
91
92double SqrtUpVariableTransformation::Ext2int(double value, double upper, double ) const {
93 // external to internal transformation
94 double yy = upper - value + 1.;
95 double arg = yy*yy - 1;
96 return ( arg < 0 ) ? 0 : std::sqrt(arg);
97}
98
99
100double SqrtUpVariableTransformation::DInt2Ext(double value, double, double) const {
101 // derivative of internal to external transofrmation : d Ext / d Int
102 double val = - value/( std::sqrt( value*value + 1.) );
103 return val;
104}
105
106
107 } // end namespace Math
108
109} // end namespace ROOT
110
Option_t Option_t TPoint TPoint const char GetTextMagnitude GetFillStyle GetLineColor GetLineWidth GetMarkerStyle GetTextAlign GetTextColor GetTextSize void value
double Int2ext(double value, double lower, double upper) const override
double Ext2int(double value, double lower, double upper) const override
double DInt2Ext(double value, double lower, double upper) const override
double DInt2Ext(double value, double lower, double upper) const override
double Int2ext(double value, double lower, double upper) const override
double Ext2int(double value, double lower, double upper) const override
double DInt2Ext(double value, double lower, double upper) const override
double Int2ext(double value, double lower, double upper) const override
double Ext2int(double value, double lower, double upper) const override
RVec< PromoteType< T > > cos(const RVec< T > &v)
Definition: RVec.hxx:1789
RVec< PromoteType< T > > asin(const RVec< T > &v)
Definition: RVec.hxx:1791
RVec< PromoteType< T > > atan(const RVec< T > &v)
Definition: RVec.hxx:1793
RVec< PromoteType< T > > sin(const RVec< T > &v)
Definition: RVec.hxx:1788
Namespace for new Math classes and functions.
VecExpr< UnaryOp< Sqrt< T >, VecExpr< A, T, D >, T >, T, D > sqrt(const VecExpr< A, T, D > &rhs)
This file contains a specialised ROOT message handler to test for diagnostic in unit tests.
double epsilon
Definition: triangle.c:618