ROOT::Minuit2::MnParabola Class Reference

Description

This class defines a parabola of the form a*x*x + b*x + c

Author

Fred James and Matthias Winkler; comments added by Andras Zsenei and Lorenzo Moneta

Definition at line 31 of file MnParabola.h.

Public Member Functions
	MnParabola (double a, double b, double c)
	~MnParabola ()
double	A () const
double	B () const
double	C () const
double	Min () const
double	X_neg (double y) const
double	X_pos (double y) const
double	Y (double x) const
double	YMin () const

Private Attributes
double	fA
double	fB
double	fC

Constructor & Destructor Documentation

MnParabola()

ROOT::Minuit2::MnParabola::MnParabola ( double  a, double  b, double  c  )

inline

Constructor that initializes the parabola with its three parameters.

Parameters

a	the coefficient of the quadratic term
b	the coefficient of the linear term
c	the constant

Definition at line 46 of file MnParabola.h.

: fA(a), fB(b), fC(c) {}

~MnParabola()

ROOT::Minuit2::MnParabola::~MnParabola ( )

inline

Definition at line 49 of file MnParabola.h.

{}

Member Function Documentation

A()

double ROOT::Minuit2::MnParabola::A ( ) const

inline

Accessor to the coefficient of the quadratic term.

Returns

the coefficient of the quadratic term.

Definition at line 138 of file MnParabola.h.

{return fA;}

References fA.

B()

double ROOT::Minuit2::MnParabola::B ( ) const

inline

Accessor to the coefficient of the linear term.

Returns

the coefficient of the linear term.

Definition at line 149 of file MnParabola.h.

{return fB;}

References fB.

C()

double ROOT::Minuit2::MnParabola::C ( ) const

inline

Accessor to the coefficient of the constant term.

Returns

the coefficient of the constant term.

Definition at line 160 of file MnParabola.h.

{return fC;}

References fC.

Min()

double ROOT::Minuit2::MnParabola::Min ( ) const

inline

Calculates the x coordinate of the Minimum of the parabola.

Returns

x coordinate of the Minimum.

Definition at line 116 of file MnParabola.h.

{return -fB/(2.*fA);}

References fA, and fB.

Referenced by X_neg(), and X_pos().

X_neg()

double ROOT::Minuit2::MnParabola::X_neg ( double  y ) const

inline

Calculates the smaller of the two x values corresponding to the given y Value.

???????!!!!!!!!! And when there is none?? it looks like it will crash?? what is sqrt (-1.0) ?

Parameters

y	the y Value for which the x Value is to be calculated.

Returns

the smaller one of the two corresponding values.

Definition at line 105 of file MnParabola.h.

{return (-sqrt(y/fA + Min()*Min() - fC/fA) + Min());}

References fA, fC, and Min().

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X_pos()

double ROOT::Minuit2::MnParabola::X_pos ( double  y ) const

inline

Calculates the bigger of the two x values corresponding to the given y Value.

???????!!!!!!!!! And when there is none?? it looks like it will crash?? what is sqrt (-1.0) ?

Parameters

y	the y Value for which the x Value is to be calculated.

Returns

the bigger one of the two corresponding values.

Definition at line 83 of file MnParabola.h.

{return (sqrt(y/fA + Min()*Min() - fC/fA) + Min());}

References fA, fC, and Min().

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Y()

double ROOT::Minuit2::MnParabola::Y ( double  x ) const

inline

Evaluates the parabola a the point x.

Parameters

x	the coordinate where the parabola needs to be evaluated.

Returns

the y coordinate of the parabola corresponding to x.

Definition at line 62 of file MnParabola.h.

{return (fA*x*x + fB*x +fC);}

References fA, fB, and fC.

YMin()

double ROOT::Minuit2::MnParabola::YMin ( ) const

inline

Calculates the y coordinate of the Minimum of the parabola.

Returns

y coordinate of the Minimum.

Definition at line 127 of file MnParabola.h.

{return (-fB*fB/(4.*fA) + fC);}

References fA, fB, and fC.

Member Data Documentation

fA

double ROOT::Minuit2::MnParabola::fA

private

Definition at line 164 of file MnParabola.h.

Referenced by A(), Min(), X_neg(), X_pos(), Y(), and YMin().

fB

double ROOT::Minuit2::MnParabola::fB

private

Definition at line 165 of file MnParabola.h.

Referenced by B(), Min(), Y(), and YMin().

fC

double ROOT::Minuit2::MnParabola::fC

private

Definition at line 166 of file MnParabola.h.

Referenced by C(), X_neg(), X_pos(), Y(), and YMin().

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

• /home/build/builds/o5h8MZZm/0/mlz/bornagain/Fit/3rdparty/RootMinimizers/Minuit2/MnParabola.h