Class to perform template fit on TOP waveform data Minimzation method is described here http://wwwa1.kph.uni-mainz.de/Vorlesungen/SS11/Statistik/. More...

#include <TOPTemplateFitter.h>

Classes
struct	FitResult
	structure holding values from template fit More...

struct	MinimizationSums
	Variables used during template fit minimization. More...

struct	TemplateParameters
	Parameters of the template function. More...

Public Member Functions
	TOPTemplateFitter (const TOPRawWaveform &wf, const TOPSampleTimes &sampleTimes, const double averageRMS)
	full constructor

	~TOPTemplateFitter ()
	default destructor

double	getChisq () const
	Returns fit chi square.

const std::vector< double > &	getChisqVector () const
	Returns calculated chisq values.

const FitResult &	getFitResult () const
	Returns fitted values with errors.

void	performTemplateFit (const double risingEdgeStart, const double fitRange)
	Prepares data and performs the template fit in sample space.

Static Public Member Functions
static TemplateParameters &	getTemplateParameters ()
	Returns the template parameters.

static int	getTemplateSamples ()
	Returns the total number of template samples.

static int	getTemplateResolution ()
	Returns the template resolution.

static bool	getUseParabola ()
	Returns useParabola.

static void	setTemplateParameters (const TemplateParameters &params)
	Sets the template parameters.

static void	setTemplateSamples (int nSamples)
	Set the total number of template samples.

static void	setTemplateResolution (int resolution)
	Set the template resolution.

static void	setUseParabola (bool use)
	Enable Usage of parabola improvement.

static void	InitializeTemplateFit ()
	Intializes the template fit using default values.

Private Member Functions
void	PerformTemplateFitMinimize (const std::vector< short > &samples, const std::vector< short > &pedestals, const std::vector< float > &timingCorrection, const double risingEdgeCFD, const double fitRange)
	performs the template fit

double	ComputeMinimizedParametersAndChisq (const MinimizationSums &sums, FitResult &result)
	Compute the minimized parameters and chi square value.

void	CalculateParabolaVertex (const Point &p1, const Point &p2, const Point &p3, Point &vertex)
	Calculate vertex coordinates of parabola given three data points.

Private Attributes
const TOPRawWaveform	m_wf
	raw sampled waveforms

const TOPSampleTimes	m_sampleTimes
	provides timing correction

const double	m_averageRMS
	average RMS of waveform samples, no database for this

FitResult	m_result
	fit result from template fit

double	m_chisq = 0
	chi square value from template fit

std::vector< double >	m_chisq_vec
	all computed chi square values from template fit

Static Private Attributes
static int	s_totalTemplateSamples = 64
	number of samples used for template

static int	s_templateResolution = 4
	resolution of template with respect to normal sample spacing

static TemplateParameters	s_templateParameters
	parameters used for the template calculation

static std::vector< double >	s_templateSamples
	precomputed template samples

static int	s_fineOffsetRange = TOPTemplateFitter::s_templateResolution * 5
	range for offset between template and signal

static bool	s_templateReInitialize = true
	flag showing that the template samples have to be recomputed

static bool	s_useParabola = true
	try improving fit by making use of parabolic shape of chisq values

Detailed Description

Class to perform template fit on TOP waveform data Minimzation method is described here http://wwwa1.kph.uni-mainz.de/Vorlesungen/SS11/Statistik/.

Definition at line 30 of file TOPTemplateFitter.h.

Constructor & Destructor Documentation

◆ TOPTemplateFitter()

TOPTemplateFitter	(	const TOPRawWaveform &	wf,
		const TOPSampleTimes &	sampleTimes,
		const double	averageRMS
	)

full constructor

Parameters

wf	TOP raw waveform samples
sampleTimes	database object holding time correction
averageRMS	average sample RMS

Definition at line 28 of file TOPTemplateFitter.cc.

  : m_wf(wf), m_sampleTimes(sampleTimes), m_averageRMS(averageRMS)
{
  m_chisq = -1.;
  if (s_templateReInitialize) {
    InitializeTemplateFit();
  }
}

◆ ~TOPTemplateFitter()

~TOPTemplateFitter ( )

inline

default destructor

Definition at line 103 of file TOPTemplateFitter.h.

103{};

Member Function Documentation

◆ CalculateParabolaVertex()

void CalculateParabolaVertex	(	const Point &	p1,
		const Point &	p2,
		const Point &	p3,
		Point &	vertex
	)

private

Calculate vertex coordinates of parabola given three data points.

Parameters

p1	data point 1
p2	data point 2
p3	data point 3
vertex	vertex position

Definition at line 108 of file TOPTemplateFitter.cc.

{
  double denom = (p1.first - p2.first) * (p1.first - p3.first) * (p2.first - p3.first);
  double a     = (p3.first * (p2.second - p1.second) + p2.first * (p1.second - p3.second) + p1.first *
                  (p3.second - p2.second)) / denom;
  double b     = (p3.first * p3.first * (p1.second - p2.second) + p2.first * p2.first * (p3.second - p1.second)
                  + p1.first * p1.first * (p2.second - p3.second)) / denom;
  double c     = (p2.first * p3.first * (p2.first - p3.first) * p1.second + p3.first * p1.first * (p3.first - p1.first) * p2.second
                  + p1.first * p2.first * (p1.first - p2.first) * p3.second) / denom;
 
  vertex.first = -b / (2 * a);
  vertex.second = c - b * b / (4 * a);
}

◆ ComputeMinimizedParametersAndChisq()

double ComputeMinimizedParametersAndChisq	(	const MinimizationSums &	sums,
		FitResult &	result
	)

private

Compute the minimized parameters and chi square value.

Parameters

sums	minimization sums for chisq calculation
result	minimized parameters

Returns: chi square

Definition at line 165 of file TOPTemplateFitter.cc.

{
  const double determinant = sums.S1 * sums.Sxx - sums.Sx * sums.Sx;
  result.amplitude = (-sums.Sx * sums.Sy + sums.S1 * sums.Sxy) / determinant;
  result.backgroundOffset = (sums.Sxx * sums.Sy - sums.Sx * sums.Sxy) / determinant;
  result.amplitudeError = sums.S1 / determinant;
  result.backgroundOffsetError = sums.Sxx / determinant;
  return sums.Syy - result.backgroundOffset * sums.Sy - result.amplitude * sums.Sxy;
}

◆ getChisq()

double getChisq ( ) const

inline

Returns fit chi square.

Returns: fit chi square

Definition at line 109 of file TOPTemplateFitter.h.

109{return m_chisq;}

◆ getChisqVector()

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

inline

Returns calculated chisq values.

Returns: chisq vector

Definition at line 115 of file TOPTemplateFitter.h.

115{return m_chisq_vec;}

Belle2::TOP::TOPTemplateFitter::m_chisq_vec

std::vector< double > m_chisq_vec

all computed chi square values from template fit

Definition: TOPTemplateFitter.h:231

◆ getFitResult()

const FitResult & getFitResult ( ) const

inline

Returns fitted values with errors.

Returns: fitted values with errors

Definition at line 121 of file TOPTemplateFitter.h.

121{return m_result;}

Belle2::TOP::TOPTemplateFitter::m_result

FitResult m_result

fit result from template fit

Definition: TOPTemplateFitter.h:229

◆ getTemplateParameters()

static TemplateParameters & getTemplateParameters ( )

inlinestatic

Returns the template parameters.

Returns: template parameters

Definition at line 127 of file TOPTemplateFitter.h.

127{return s_templateParameters;}

Belle2::TOP::TOPTemplateFitter::s_templateParameters

static TemplateParameters s_templateParameters

parameters used for the template calculation

Definition: TOPTemplateFitter.h:222

◆ getTemplateResolution()

static int getTemplateResolution ( )

inlinestatic

Returns the template resolution.

Returns: template resolution

Definition at line 139 of file TOPTemplateFitter.h.

139{return s_templateResolution;}

Belle2::TOP::TOPTemplateFitter::s_templateResolution

static int s_templateResolution

resolution of template with respect to normal sample spacing

Definition: TOPTemplateFitter.h:221

◆ getTemplateSamples()

static int getTemplateSamples ( )

inlinestatic

Returns the total number of template samples.

Returns: total number of template samples

Definition at line 133 of file TOPTemplateFitter.h.

133{return s_totalTemplateSamples;}

Belle2::TOP::TOPTemplateFitter::s_totalTemplateSamples

static int s_totalTemplateSamples

number of samples used for template

Definition: TOPTemplateFitter.h:220

◆ getUseParabola()

static bool getUseParabola ( )

inlinestatic

Returns useParabola.

Returns: useParabola

Definition at line 145 of file TOPTemplateFitter.h.

145{return s_useParabola;}

Belle2::TOP::TOPTemplateFitter::s_useParabola

static bool s_useParabola

try improving fit by making use of parabolic shape of chisq values

Definition: TOPTemplateFitter.h:226

◆ InitializeTemplateFit()

void InitializeTemplateFit ( )

static

Intializes the template fit using default values.

Definition at line 59 of file TOPTemplateFitter.cc.

{
  s_templateSamples.clear();
  if (s_templateParameters.risingEdge < 0 || s_templateParameters.risingEdge > s_totalTemplateSamples) {
    B2FATAL("rising edge of template function invalid!");
  }
 
  const auto* geo = TOPGeometryPar::Instance()->getGeometry();
  const auto& signalShape = geo->getSignalShape();
  const auto& tdc = geo->getNominalTDC();
  const double dt = tdc.getSampleWidth();
 
  for (double x = 0; x < s_totalTemplateSamples; x += 1. / s_templateResolution) {
    s_templateSamples.push_back(s_templateParameters.amplitude * signalShape.getValue((x - s_templateParameters.risingEdge)*dt));
  }
 
  s_templateReInitialize = false;
}

◆ performTemplateFit()

void performTemplateFit	(	const double	risingEdgeStart,
		const double	fitRange
	)

Prepares data and performs the template fit in sample space.

Parameters

risingEdgeStart	initial guess for rising edge position from CFD
fitRange	range of template fit

Definition at line 78 of file TOPTemplateFitter.cc.

{
  if (s_templateReInitialize) {
    InitializeTemplateFit();
  }//do this here to make sure nobody changed template settings? -> thread safety?
 
  //access time base correction and calculate correction to waveform sample number
  vector<short> pedestals(m_wf.getSize(), m_averageRMS);//for now assume constant pedestals for TOP
  vector<float> timingCorrection(m_wf.getSize(),
                                 0.);//timing correction, should be relative to each sample in in units of samples -> pick correct template sample
 
  //perform template fit
  m_chisq_vec.clear();
  m_chisq = 1e6;
  PerformTemplateFitMinimize(m_wf.getWaveform(), pedestals, timingCorrection, risingEdgeStart, fitRange);
 
  //use paraboic shape of chi^2 distribution to improve fit result
  if (s_useParabola) {
    auto it = std::min_element(std::begin(m_chisq_vec), std::end(m_chisq_vec));
    int minidx = std::distance(std::begin(m_chisq_vec), it);
    if (minidx > 0 && minidx < (int)m_chisq_vec.size() - 1) {
      Point vertex;
      CalculateParabolaVertex({ -1, m_chisq_vec[minidx - 1]}, {0, m_chisq_vec[minidx]}, {1, m_chisq_vec[minidx + 1]}, vertex);
      m_chisq = vertex.second;
      m_result.risingEdge += vertex.first / s_templateResolution;
    }
  }
}

◆ PerformTemplateFitMinimize()

void PerformTemplateFitMinimize	(	const std::vector< short > &	samples,
		const std::vector< short > &	pedestals,
		const std::vector< float > &	timingCorrection,
		const double	risingEdgeCFD,
		const double	fitRange
	)

private

performs the template fit

Parameters

samples	sample vector
pedestals	pedestal vector
timingCorrection	timing correction for samples
risingEdgeCFD	rising edge from constant fraction discrimination
fitRange	fit range

Definition at line 122 of file TOPTemplateFitter.cc.

{
  if (samples.size() != pedestals.size() || samples.size() != timingCorrection.size()) {
    B2FATAL("Size of sample, pedestal and timing correction vectors has to be equal!");
  }
 
 
  MinimizationSums sums;
  FitResult result;
  int initialOffset = risingEdgeCFD - s_templateParameters.risingEdge;
  //offset search loop
  for (int fineOffset = -s_fineOffsetRange; fineOffset < s_fineOffsetRange; ++fineOffset) {
    sums.clear();
    int totalTemplateOffset = initialOffset * s_templateResolution + fineOffset;
    for (int signalSampleIndex = risingEdgeCFD - fitRange; signalSampleIndex < risingEdgeCFD + fitRange; ++signalSampleIndex) {
      if (signalSampleIndex < 0 || signalSampleIndex > (int)samples.size() - 1) continue;
      int templateIndex = signalSampleIndex * s_templateResolution - totalTemplateOffset + timingCorrection[signalSampleIndex];
      if (templateIndex < 0 || templateIndex > (int) s_templateSamples.size() - 1) continue;
      double weight = 1. / (pedestals[signalSampleIndex] * pedestals[signalSampleIndex]);
      double Sx = weight * s_templateSamples[templateIndex];
      double Sy = weight * samples[signalSampleIndex];
      sums.S1 += weight;
      sums.Sx += Sx;
      sums.Sy += Sy;
      sums.Sxx += Sx * s_templateSamples[templateIndex];
      sums.Sxy += Sy * s_templateSamples[templateIndex];
      sums.Syy += Sy * samples[signalSampleIndex];
    }
    double chisq = ComputeMinimizedParametersAndChisq(sums, result);
    m_chisq_vec.push_back(chisq);
    if (chisq < m_chisq) { //save minimal chisq result
      m_chisq = chisq;
      m_result = result;
      m_result.risingEdge = totalTemplateOffset;
    }
  }
  //template offset back to sample space and scale amplitude
  m_result.risingEdge = m_result.risingEdge / s_templateResolution + s_templateParameters.risingEdge;
  m_result.amplitude *= s_templateParameters.amplitude;
  m_result.amplitudeError *= s_templateParameters.amplitude;
}

◆ setTemplateParameters()

void setTemplateParameters ( const TemplateParameters & params )

static

Sets the template parameters.

Parameters

params template Parameters

Definition at line 39 of file TOPTemplateFitter.cc.

{
  s_templateParameters = params;
  s_templateReInitialize = true;
}

◆ setTemplateResolution()

void setTemplateResolution ( int resolution )

static

Set the template resolution.

Parameters

resolution template resolution

Definition at line 52 of file TOPTemplateFitter.cc.

{
  s_templateResolution = resolution;
  s_fineOffsetRange = resolution * 5;
  s_templateReInitialize = true;
}

◆ setTemplateSamples()

void setTemplateSamples ( int nSamples )

static

Set the total number of template samples.

Parameters

nSamples total number of template samples

Definition at line 45 of file TOPTemplateFitter.cc.

{
  s_totalTemplateSamples = nSamples;
  s_templateReInitialize = true;
 
}

◆ setUseParabola()

static void setUseParabola ( bool use )

inlinestatic

Enable Usage of parabola improvement.

Parameters

use	enable/disable usage

staticprivate

number of samples used for template

Definition at line 220 of file TOPTemplateFitter.h.

◆ s_useParabola

bool s_useParabola = true

staticprivate

try improving fit by making use of parabolic shape of chisq values

Definition at line 226 of file TOPTemplateFitter.h.

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

top/utilities/include/TOPTemplateFitter.h
top/utilities/src/TOPTemplateFitter.cc

Classes

Public Member Functions

Static Public Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ TOPTemplateFitter()

◆ ~TOPTemplateFitter()

Member Function Documentation

◆ CalculateParabolaVertex()

◆ ComputeMinimizedParametersAndChisq()

◆ getChisq()

◆ getChisqVector()

◆ getFitResult()

◆ getTemplateParameters()

◆ getTemplateResolution()

◆ getTemplateSamples()

◆ getUseParabola()

◆ InitializeTemplateFit()

◆ performTemplateFit()

◆ PerformTemplateFitMinimize()

◆ setTemplateParameters()

◆ setTemplateResolution()

◆ setTemplateSamples()

◆ setUseParabola()

Member Data Documentation

◆ m_averageRMS

◆ m_chisq

◆ m_chisq_vec

◆ m_result

◆ m_sampleTimes

◆ m_wf

◆ s_fineOffsetRange

◆ s_templateParameters

◆ s_templateReInitialize

◆ s_templateResolution

◆ s_templateSamples

◆ s_totalTemplateSamples

◆ s_useParabola