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 32 of file MnMachinePrecision.h.

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

Private Attributes
double	fEpsMa2
double	fEpsMac

#include <Minuit2/MnMachinePrecision.h>

Constructor & Destructor Documentation

MnMachinePrecision()

ROOT::Minuit2::MnMachinePrecision::MnMachinePrecision

(

)

Definition at line 18 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 38 of file MnMachinePrecision.h.

Eps2()

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

inline

eps2 returns 2*sqrt(eps)

Definition at line 41 of file MnMachinePrecision.h.

SetPrecision()

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

inline

override Minuit's own determination

Definition at line 44 of file MnMachinePrecision.h.

Member Data Documentation

fEpsMa2

double ROOT::Minuit2::MnMachinePrecision::fEpsMa2

private

Definition at line 56 of file MnMachinePrecision.h.

fEpsMac

double ROOT::Minuit2::MnMachinePrecision::fEpsMac

private

Definition at line 55 of file MnMachinePrecision.h.

Libraries for ROOT::Minuit2::MnMachinePrecision:

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The documentation for this class was generated from the following files:

• math/minuit2/inc/Minuit2/MnMachinePrecision.h
• math/minuit2/src/MnMachinePrecision.cxx