TRobustLineFitter Class Reference

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

#include <TRobustLineFitter.h>

Inheritance diagram for TRobustLineFitter:

Public Member Functions
	TRobustLineFitter (const std::string &name)
	Constructor.
virtual	~TRobustLineFitter ()
	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 TLineFitter
	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 TRobustLineFitter.h.

Constructor & Destructor Documentation

TRobustLineFitter()

TRobustLineFitter::TRobustLineFitter

(

const std::string &

name

)

Constructor.

Definition at line 37 of file TRobustLineFitter.cxx.

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

~TRobustLineFitter()

TRobustLineFitter::~TRobustLineFitter ( )

virtual

Destructor.

Definition at line 41 of file TRobustLineFitter.cxx.

                                      {
}

Member Function Documentation

a()

double TRobustLineFitter::a ( void  ) const

inline

Definition at line 72 of file TRobustLineFitter.h.

                               {
    return _a;
}

b()

double TRobustLineFitter::b ( void  ) const

inline

Definition at line 78 of file TRobustLineFitter.h.

                               {
    return _b;
}

det()

double TRobustLineFitter::det ( void  ) const

inline

Definition at line 84 of file TRobustLineFitter.h.

                                 {
    return _det;
}

dump()

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

dumps debug information.

fit()

int TRobustLineFitter::fit ( TTrackBase &  t ) const

virtual

Reimplemented from TLineFitter.

Definition at line 45 of file TRobustLineFitter.cxx.

                                           {
    //...Initial guess...
    int err = TLineFitter::fit(t);
    if (err) return err;
 
    //...Check # of hits...
    const AList<TMLink> & links = t.links();
    _n = links.length();
    if (_n < 3) return 0;
 
    //...Standard deviation...
    _a = TLineFitter::a();
    _b = TLineFitter::b();
    _det = TLineFitter::det();
    double chisq = 0.;
    for (unsigned i = 0; i < _n; i++) {
    const HepPoint3D & p = links[i]->position();
    double tmp = p.y() - (_a * p.x() + _b);
    chisq += tmp * tmp;
    }
    double siga = sqrt(chisq / _det);
 
    //...Decide iteration step...
    double a1 = _a;
    double f1 = rofunc(t, a1);
    double a2 = _a + copysign(3.0 * siga, f1);
    double f2 = rofunc(t, a2);
 
    // if initial value f2 >f1, change the search direction
    if( f1 * f2 > 0. && fabs(f2) > fabs(f1) ){
    a2 = _a - copysign(3.0 * siga, f1);
    f2 = rofunc(t, a2);
    }
 
    int backwardSearch=0;
    while (f1 * f2 > 0. ) {
      _a = 2.0 * a2 - a1;
      a1 = a2;
      f1 = f2;
      a2 = _a;
      f2 = rofunc(t, a2);
 
      if( f1 * f2 > 0. && ( fabs(f2) > fabs(f1) || fabs(f2-f1)<0.01 ) ){
    backwardSearch++;
    if(backwardSearch==2){
      break;
    }
 
    double f=f2;
    a2 = a1;
    f2 = f1;
    a1 = _a;
    f1 = f;
      }
    }
 
    if(backwardSearch==2){
      // for case of  no zero cross
      //search minimun fabs(f)
 
      double siga1 = 0.01 * siga;
      double a21(fabs(a2-a1));
      while (a21 > siga1) {
    _a = 0.5 * (a1 + a2);
    if (_a == a1 || _a == a2) break;
    double f = rofunc(t, _a);
 
    if( f * f1 <0 ){
      f1=f;
      a1=_a;
      backwardSearch--;
      break;
    }
 
    if ( fabs(f) <= fabs(f1) && fabs(f) <= fabs(f2)) {
      if( fabs(f-f1) > fabs(f-f2) ){
        f1 = f;
        a1 = _a;
      }else{
        f2 = f;
        a2 = _a;
      }
    }else if( fabs(f) <= fabs(f1) ){
      f1 = f;
      a1 = _a;
    }else if ( fabs(f) <= fabs(f2) ){
      f2 = f;
      a2 = _a;
    }else{
      if( fabs(f2) > fabs(f1) ){
        f1=f;
        a1 = _a;
      }else{
        f2 = f;
        a2 = _a;
      }
    }
    if (fabs(a2-a1) >= a21) break;
    a21 = fabs(a2-a1);
      }
    }
 
    if(backwardSearch<=1){
 
      //search zero cross
      siga = 0.01 * siga;
 
      double a21(fabs(a2-a1));
      while (a21 > siga) {
    _a = 0.5 * (a1 + a2);
    if (_a == a1 || _a == a2) break;
    double f = rofunc(t, _a);
    if (f * f1 >= 0.) {
      f1 = f;
      a1 = _a;
    }
    else {
      f2 = f;
      a2 = _a;
    }
    if (fabs(a2-a1) >= a21) break;
    a21 = fabs(a2-a1);
      }
    }
 
    _det = _det / double(_n);
 
    if (t.objectType() == Line)
    ((TMLine &) t).property(_a, _b, _det);
    fitDone(t);
    return 0;
}

Referenced by TBuilder::buildStereo(), TBuilderCurl::buildStereo(), TBuilder::initialLine2(), and TBuilder::searchLine().

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

• TRobustLineFitter.h
• TRobustLineFitter.cxx