TLineFitter Class Reference

A class to fit a TTrackBase object to a line. More...

#include <TLineFitter.h>

Inheritance diagram for TLineFitter:

Public Member Functions
	TLineFitter (const std::string &name)
	Constructor.
virtual	~TLineFitter ()
	Destructor.
void	dump (const std::string &message=std::string(""), const std::string &prefix=std::string("")) const
	dumps debug information.
double	a (void) const
double	b (void) const
double	det (void) const
virtual int	fit (TTrackBase &) const
Public Member Functions inherited from TMFitter
	TMFitter (const std::string &name)
	Constructor.
virtual	~TMFitter ()
	Destructor.
const std::string &	name (void) const
	returns name.
void	dump (const std::string &message=std::string(""), const std::string &prefix=std::string("")) const
virtual int	fit (TTrackBase &) const =0

Additional Inherited Members
Protected Member Functions inherited from TMFitter
void	fitDone (TTrackBase &) const
	sets the fitted flag. (Bad implementation)

Detailed Description

A class to fit a TTrackBase object to a line.

Definition at line 28 of file TLineFitter.h.

Constructor & Destructor Documentation

TLineFitter()

TLineFitter::TLineFitter

(

const std::string &

name

)

Constructor.

Definition at line 18 of file TLineFitter.cxx.

: TMFitter(name), _a(0.), _b(0.), _det(0.) {
}

~TLineFitter()

TLineFitter::~TLineFitter ( )

virtual

Destructor.

Definition at line 22 of file TLineFitter.cxx.

                          {
}

Member Function Documentation

a()

double TLineFitter::a ( void  ) const

inline

Definition at line 67 of file TLineFitter.h.

                         {
    return _a;
}

Referenced by TRobustLineFitter::fit().

b()

double TLineFitter::b ( void  ) const

inline

Definition at line 73 of file TLineFitter.h.

                         {
    return _b;
}

Referenced by TRobustLineFitter::fit().

det()

double TLineFitter::det ( void  ) const

inline

Definition at line 79 of file TLineFitter.h.

                           {
    return _det;
}

Referenced by TRobustLineFitter::fit().

dump()

void TLineFitter::dump	(	const std::string &	message = std::string(""),
		const std::string &	prefix = std::string("")
	)		const

dumps debug information.

fit()

int TLineFitter::fit ( TTrackBase &  t ) const

virtual

Implements TMFitter.

Reimplemented in TRobustLineFitter.

Definition at line 26 of file TLineFitter.cxx.

                                     {
 
    //...Already fitted ?...
    if (t.fitted()) return TFitAlreadyFitted;
 
    //...Check # of hits...
    if (t.links().length() < 2) return TFitErrorFewHits;
 
    unsigned n = t.links().length();
    if (_det == 0. && n == 2) {
    double x0 = t.links()[0]->position().x();
    double y0 = t.links()[0]->position().y();
    double x1 = t.links()[1]->position().x();
    double y1 = t.links()[1]->position().y();
    if (x0 == x1) return TFitFailed;
    _a = (y0 - y1) / (x0 - x1);
    _b = - _a * x1 + y1;
    }
    else {
    double sum = (double) n;
    double sumX = 0., sumY = 0., sumX2 = 0., sumXY = 0., sumY2 = 0.;
    for (unsigned i = 0; i < n; i++) {
        const HepPoint3D & p = t.links()[i]->position();
        double x = p.x();
        double y = p.y();
        sumX  += x;
        sumY  += y;
        sumX2 += x * x;
        sumXY += x * y;
        sumY2 += y * y;
    }
 
    _det = sum * sumX2 - sumX * sumX;
#ifdef TRKRECO_DEBUG_DETAIL
    cout << "        TLineFitter::fit ... det=" << _det << std::endl;
#endif
    if (_det == 0.) {
        return TFitFailed;
    }
    else {
        _a = (sumXY * sum - sumX * sumY) / _det;
        _b = (sumX2 * sumY - sumX * sumXY) / _det;
    }
    }
 
    if (t.objectType() == Line)
    ((TMLine &) t).property(_a, _b, _det);
    fitDone(t);
    return 0;
}

Referenced by TRobustLineFitter::fit().

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

• TLineFitter.h
• TLineFitter.cxx