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Reference Guide
ROOT::Minuit2::MnMachinePrecision Class Reference

Sets the relative floating point (double) arithmetic precision.

By default the precision values are obtained from the standard functions std::numeric_limits<double>::epsilon. The values can optionally be computed directly using the ComputePrecision() member function. For a IEEE standard floating point arithmetic the computed values and the one from std::numeric_limits<double>::epsilon are the same.

SetPrecision() method can instead be used to override Minuit's own determination, when the user knows that the {FCN} function Value is not calculated to the nominal machine accuracy.

Definition at line 33 of file MnMachinePrecision.h.

Public Member Functions

 MnMachinePrecision ()
 
void ComputePrecision ()
 compute Machine precision directly instead of using default values from std::numeric_limits More...
 
double Eps () const
 eps returns the smallest possible number so that 1.+eps > 1. More...
 
double Eps2 () const
 eps2 returns 2*sqrt(eps) More...
 
void SetPrecision (double prec)
 override Minuit's own determination More...
 

Private Attributes

double fEpsMa2
 
double fEpsMac
 

#include <Minuit2/MnMachinePrecision.h>

Constructor & Destructor Documentation

◆ MnMachinePrecision()

ROOT::Minuit2::MnMachinePrecision::MnMachinePrecision ( )

Definition at line 19 of file MnMachinePrecision.cxx.

Member Function Documentation

◆ ComputePrecision()

void ROOT::Minuit2::MnMachinePrecision::ComputePrecision ( )

compute Machine precision directly instead of using default values from std::numeric_limits

Definition at line 29 of file MnMachinePrecision.cxx.

◆ Eps()

double ROOT::Minuit2::MnMachinePrecision::Eps ( ) const
inline

eps returns the smallest possible number so that 1.+eps > 1.

Definition at line 41 of file MnMachinePrecision.h.

◆ Eps2()

double ROOT::Minuit2::MnMachinePrecision::Eps2 ( ) const
inline

eps2 returns 2*sqrt(eps)

Definition at line 44 of file MnMachinePrecision.h.

◆ SetPrecision()

void ROOT::Minuit2::MnMachinePrecision::SetPrecision ( double  prec)
inline

override Minuit's own determination

Definition at line 47 of file MnMachinePrecision.h.

Member Data Documentation

◆ fEpsMa2

double ROOT::Minuit2::MnMachinePrecision::fEpsMa2
private

Definition at line 59 of file MnMachinePrecision.h.

◆ fEpsMac

double ROOT::Minuit2::MnMachinePrecision::fEpsMac
private

Definition at line 58 of file MnMachinePrecision.h.

Libraries for ROOT::Minuit2::MnMachinePrecision:
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The documentation for this class was generated from the following files: