KVImpactParameters::algebraic_fitting_function Class Reference

Detailed Description

Algebraic relationship between mean value of observable and centrality.

This class implements the relationship between the mean value of an observable and centrality

\[ k(c_b) = (k_{\mathrm{max}}-k_{\mathrm{min}})\left[ 1 - {c_b}^{\alpha}\right]^{\gamma} + k_{\mathrm{min}} \]

used in Frankland et al., Phys. Rev. C xx, yy(2020), describing the centrality dependence of the mean value of an observable which decreases monotonically with impact parameter. This function is guaranteed to be mononotonic in the range \(c_b=[0,1]\) for all values of the parameters \(\alpha,\gamma>0\).

See also

bayesian_estimator

Definition at line 25 of file algebraic_fitting_function.h.

#include <algebraic_fitting_function.h>

Classes
class	bce_fit_results
	Contains fit parameters for algebraic impact parameter dependence. More...

Public Member Functions
	algebraic_fitting_function ()
	algebraic_fitting_function (const algebraic_fitting_function &)
	Copy parameters from other. More...
	algebraic_fitting_function (double alph, double gam, double thet, double Xmi, double Xma)
void	backup_params ()
void	fill_array_from_params (double *p) const
void	fill_params_from_array (double *p)
double	k_cb (double cb) const
double	meanX (double cb) const
void	normalise_shape_function ()
int	npar () const
void	print_fit_params () const
double	redVar (double) const
void	restore_params ()
void	set_initial_parameters (TH1 *h, TF1 &f)
void	set_par_names (TF1 &f) const
double	theta () const

Private Attributes
class KVImpactParameters::algebraic_fitting_function::bce_fit_results	param_backup
class KVImpactParameters::algebraic_fitting_function::bce_fit_results	params

Constructor & Destructor Documentation

algebraic_fitting_function() [1/3]

KVImpactParameters::algebraic_fitting_function::algebraic_fitting_function ( )

inline

Definition at line 75 of file algebraic_fitting_function.h.

algebraic_fitting_function() [2/3]

KVImpactParameters::algebraic_fitting_function::algebraic_fitting_function

(

const algebraic_fitting_function &

other

)

Copy parameters from other.

Definition at line 11 of file algebraic_fitting_function.cpp.

algebraic_fitting_function() [3/3]

KVImpactParameters::algebraic_fitting_function::algebraic_fitting_function	(	double	alph,
		double	gam,
		double	thet,
		double	Xmi,
		double	Xma
	)

Use parameter values from previous fit

Parameters

[in]	alph	\(\alpha\)
[in]	gam	\(\gamma\)
[in]	thet	\(\theta\)
[in]	Xmi	\(X_{min}\)
[in]	Xma	\(X_{max}\)

Definition at line 26 of file algebraic_fitting_function.cpp.

Member Function Documentation

backup_params()

void KVImpactParameters::algebraic_fitting_function::backup_params ( )

inline

Store current values of parameters

Definition at line 78 of file algebraic_fitting_function.h.

fill_array_from_params()

void KVImpactParameters::algebraic_fitting_function::fill_array_from_params

(

double *

p

)

const

Copy values of parameters into the array (interface to ROOT TF1)

Parameters

[in]	p	address of an array of size given by npar()
[in]	p[0]	\(\theta\)
[in]	p[1]	\(X_{max}\)
[in]	p[2]	\(X_{min}\)
[in]	p[3]	\(\alpha\)
[in]	p[4]	\(\gamma\)

Definition at line 80 of file algebraic_fitting_function.cpp.

fill_params_from_array()

void KVImpactParameters::algebraic_fitting_function::fill_params_from_array

(

double *

p

)

Set values of parameters from values in the array (interface to ROOT TF1)

Parameters

[in]	p	address of an array of size given by npar()
[in]	p[0]	\(\theta\)
[in]	p[1]	\(X_{max}\)
[in]	p[2]	\(X_{min}\)
[in]	p[3]	\(\alpha\)
[in]	p[4]	\(\gamma\)

Definition at line 59 of file algebraic_fitting_function.cpp.

k_cb()

double KVImpactParameters::algebraic_fitting_function::k_cb

(

double

cb

)

const

Calculate and return value of \(k(c_b)\) for given centrality

Parameters

[in]

cb

centrality

Definition at line 38 of file algebraic_fitting_function.cpp.

meanX()

double KVImpactParameters::algebraic_fitting_function::meanX ( double  cb ) const

inline

Definition at line 113 of file algebraic_fitting_function.h.

normalise_shape_function()

void KVImpactParameters::algebraic_fitting_function::normalise_shape_function ( )

inline

Modify values of parameters so that \(k(c_b)\) varies between 1 at \(c_b=0\) to 0 at \(c_b=1\).

Definition at line 88 of file algebraic_fitting_function.h.

npar()

int KVImpactParameters::algebraic_fitting_function::npar ( ) const

inline

Definition at line 96 of file algebraic_fitting_function.h.

print_fit_params()

void KVImpactParameters::algebraic_fitting_function::print_fit_params ( ) const

inline

Definition at line 109 of file algebraic_fitting_function.h.

redVar()

double KVImpactParameters::algebraic_fitting_function::redVar ( double  ) const

inline

Definition at line 117 of file algebraic_fitting_function.h.

restore_params()

void KVImpactParameters::algebraic_fitting_function::restore_params ( )

inline

Restore previously stored parameter values

Definition at line 83 of file algebraic_fitting_function.h.

set_initial_parameters()

void KVImpactParameters::algebraic_fitting_function::set_initial_parameters	(	TH1 *	h,
		TF1 &	f
	)

Set initial values for parameters in TF1 object based on data in histogram h

Parameters

[in]	h	histogram with data (inclusive distribution of observable, \(P(X)\)) to be fitted
[in,out]	f	ROOT function using this implementation of \(k(c_b)\)

Definition at line 107 of file algebraic_fitting_function.cpp.

set_par_names()

void KVImpactParameters::algebraic_fitting_function::set_par_names

(

TF1 &

f

)

const

Set name of parameters in TF1 object

Parameters

[in,out]

f

ROOT function using this implementation of \(k(c_b)\)

Definition at line 95 of file algebraic_fitting_function.cpp.

theta()

double KVImpactParameters::algebraic_fitting_function::theta ( ) const

inline

Definition at line 103 of file algebraic_fitting_function.h.

Member Data Documentation

param_backup

class KVImpactParameters::algebraic_fitting_function::bce_fit_results KVImpactParameters::algebraic_fitting_function::param_backup

private

params

class KVImpactParameters::algebraic_fitting_function::bce_fit_results KVImpactParameters::algebraic_fitting_function::params

private