Waveform fitter class. More...

#include <WaveFitter.h>

Collaboration diagram for WaveFitter:

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Public Types
typedef std::function< double(double)>	wave_function_type
	Function type for waveform.

typedef std::vector< std::array< double, 6 > >	strip_data_type
	Function type for cluster data.

Public Member Functions
	WaveFitter (wave_function_type wave, std::array< double, 6 > times)
	Constructor creates an empty fitter with default settings. More...

void	addData (const std::array< double, 6 > &inpData, double rmsNoise)
	Add strip data to the fitter. More...

void	reset ()
	Reset fitter data.

double	getFittedTime ()
	Retrieve fitted time shift value after a fit. More...

double	getFittedTimeError ()
	Retrieve error of time shift value after a fit. More...

const std::vector< double > &	getFittedAmplitudes ()
	Retrieve strip amplitudes after a fit. More...

const std::vector< double > &	getFittedAmplitudeErrors ()
	Retrieve errors of strip amplitudes after a fit. More...

double	getFitLikelihood ()
	Return negative log-likelihood for the fit. More...

const strip_data_type &	getData () const
	Get original fitted data. More...

const strip_data_type &	getFitData ()
	Get fitted values for all samples. More...

double	getDt () const
	Get sampling interval.

const std::array< double, 6 > &	getTimes () const
	Get sample times.

double	Chi (double t)
	Get standardized chi2 for a given time shift. More...

double	negLogLikelihood (double t)
	Get negative profile log-likelihood for a given time shift. More...

double	pSignal ()
	Calculate probability of the hit being a signal, with given priors for signal and background.

double	lrSignal (double a, double b)
	Calculate likelihood ratio Lsignal/Lbackground for acceptance (signal) window given as arguments. More...

double	wave (double t) const
	Get unit waveform value at a given time.

Static Public Member Functions
static void	setPrecision (int ndigits)
	Set precision of the minimzer.

Private Member Functions
void	doFit ()
	Perform fit on the data.

void	calculateAmplitudes ()
	Calculate amplitudes.

void	calculateFitErrors ()
	Calculate fit errors. More...

void	calculateFittedData ()
	Calculate fitted data.

double	integral12 (double lower, double upper, std::function< double(double)> f)
	High-order Gauss-Legendre quadrature for likelihood integrals.

double	integral20 (double lower, double upper, std::function< double(double)> f)
	High-order Gauss-Legendre quadrature for likelihood integrals.

Private Attributes
bool	m_hasFit
	Are fit results available?

double	m_dt
	Time interval between samples.

strip_data_type	m_data
	Vector of sextets of APV samples.

std::vector< double >	m_noises
	RMS noise for strips.

std::array< double, 6 >	m_times
	Vector of sample times.

wave_function_type	m_wave
	Waveform function.

double	m_fittedTime
	Time from interval (-dt,+dt).

double	m_fittedTimeError
	Error estimate of the fitted time.

std::vector< double >	m_fittedAmplitudes
	Fitted amplitudes of the sample.

std::vector< double >	m_fittedAmplitudeErrors
	Fitted amplitude errors.

double	m_fittedLik
	Chi2 from the current fit.

int	m_ndf
	Degrees of freedom of the fit.

strip_data_type	m_fittedData
	Fitted values from current fit.

Static Private Attributes
static int	s_minimizer_precision = 6
	minimizer precision

Detailed Description

Waveform fitter class.

Definition at line 60 of file WaveFitter.h.

Constructor & Destructor Documentation

◆ WaveFitter()

WaveFitter	(	wave_function_type	wave,
		std::array< double, 6 >	times
	)

inline

Constructor creates an empty fitter with default settings.

Parameters

wave	Wave function to use for fitting data
times	array of points in time at which data are taken

Definition at line 72 of file WaveFitter.h.

Member Function Documentation

◆ addData()

void addData	(	const std::array< double, 6 > &	inpData,
		double	rmsNoise
	)

inline

Add strip data to the fitter.

Parameters

inpData	array of 6 APV signals.
rmsNoise	RMS noise for the strip.

Definition at line 82 of file WaveFitter.h.

◆ calculateFitErrors()

void calculateFitErrors ( )

private

Calculate fit errors.

This only calculates local (linearization) errors.

Definition at line 134 of file WaveFitter.cc.

 {
   // Errors on amplitudes - simple from the linear model
   double sum_w2 = 0;
   for (int i = 0; i < 6; ++i) {
     double wave = m_wave(m_times[i] - m_fittedTime);
     sum_w2 += wave * wave;
   }
   double one_by_sqrtSumw2 = 1.0 / sqrt(sum_w2);
   for (unsigned int row = 0; row < m_data.size(); ++row)
     m_fittedAmplitudeErrors.push_back(one_by_sqrtSumw2 * m_noises[row]);
   // For time: ignore correlation with amplitudes
   // We will need derivatives, calculate them numerically
   double timestep = 0.1 * m_dt;
   double dwave_sq = 0;
   for (int i = 0; i < 6; ++i) {
     double dwave = (wave(m_times[i] - m_fittedTime + 0.5 * timestep) - wave(m_times[i] - m_fittedTime - 0.5 * timestep)) / timestep;
     dwave_sq += dwave * dwave;
   }
   double sn_sq = 0;
   for (unsigned int row = 0; row < m_data.size(); ++row) {
     double sn = m_fittedAmplitudes[row] / m_noises[row];
     sn_sq += sn * sn;
   }
   m_fittedTimeError = 1.0 / sqrt(sn_sq * dwave_sq);
 }

◆ Chi()

double Chi ( double t )

Get standardized chi2 for a given time shift.

Parameters

t	time shift

Returns: chi2/ndf at a given time shift

Definition at line 24 of file WaveFitter.cc.

◆ getData()

const strip_data_type& getData ( void ) const

inline

Get original fitted data.

Returns: vector of arrays of strip data used in the fit.

Definition at line 152 of file WaveFitter.h.

◆ getFitData()

const strip_data_type& getFitData ( )

inline

Get fitted values for all samples.

Returns: vector of arrays of fit estimates of fitted data.

Definition at line 157 of file WaveFitter.h.

◆ getFitLikelihood()

double getFitLikelihood ( )

inline

Return negative log-likelihood for the fit.

Returns: negative log-likelihood for the fit

Definition at line 143 of file WaveFitter.h.

◆ getFittedAmplitudeErrors()

const std::vector<double>& getFittedAmplitudeErrors ( )

inline

Retrieve errors of strip amplitudes after a fit.

Returns: vector<double> of errors of strip amplitude estimates

Definition at line 134 of file WaveFitter.h.

◆ getFittedAmplitudes()

const std::vector<double>& getFittedAmplitudes ( )

inline

Retrieve strip amplitudes after a fit.

Returns: vector<double> of strip amplitude estimates

Definition at line 125 of file WaveFitter.h.

◆ getFittedTime()

double getFittedTime ( )

inline

Retrieve fitted time shift value after a fit.

Returns: time shift estimate

Definition at line 107 of file WaveFitter.h.

◆ getFittedTimeError()

double getFittedTimeError ( )

inline

Retrieve error of time shift value after a fit.

Returns: time shift estimate error

Definition at line 116 of file WaveFitter.h.

◆ lrSignal()

double lrSignal	(	double	a,
		double	b
	)

Calculate likelihood ratio Lsignal/Lbackground for acceptance (signal) window given as arguments.

Parameters

a	lower bound of the acceptance window
b	upper bound of the acceptance window

Returns: L(in acc. w.)/L(out of acc. w.)

Definition at line 257 of file WaveFitter.cc.

◆ negLogLikelihood()

double negLogLikelihood ( double t )

Get negative profile log-likelihood for a given time shift.

Parameters

t	the time shift at which to calculate the likelihood

Returns: log-likelihood integrated over amplitudes at the given t

Definition at line 52 of file WaveFitter.cc.

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

svd/reconstruction/include/WaveFitter.h
svd/reconstruction/src/WaveFitter.cc

Public Types

Public Member Functions

Static Public Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ WaveFitter()

Member Function Documentation

◆ addData()

◆ calculateFitErrors()

◆ Chi()

◆ getData()

◆ getFitData()

◆ getFitLikelihood()

◆ getFittedAmplitudeErrors()

◆ getFittedAmplitudes()

◆ getFittedTime()

◆ getFittedTimeError()

◆ lrSignal()

◆ negLogLikelihood()