EvtItgSimpsonIntegrator Class Reference

#include <EvtItgSimpsonIntegrator.hh>

Inheritance diagram for EvtItgSimpsonIntegrator:

Public Member Functions
	EvtItgSimpsonIntegrator (const EvtItgAbsFunction &, double precision=1.0e-5, int maxLoop=20)
virtual	~EvtItgSimpsonIntegrator ()
Public Member Functions inherited from EvtItgAbsIntegrator
	EvtItgAbsIntegrator (const EvtItgAbsFunction &)
virtual	~EvtItgAbsIntegrator ()
double	evaluate (double lower, double upper) const
double	normalisation () const

Protected Member Functions
virtual double	evaluateIt (double, double) const
Protected Member Functions inherited from EvtItgAbsIntegrator
double	trapezoid (double lower, double higher, int n, double &result) const
double	myFunction (double x) const

Detailed Description

Definition at line 34 of file EvtItgSimpsonIntegrator.hh.

Constructor & Destructor Documentation

EvtItgSimpsonIntegrator()

EvtItgSimpsonIntegrator::EvtItgSimpsonIntegrator	(	const EvtItgAbsFunction &	theFunction,
		double	precision = 1.0e-5,
		int	maxLoop = 20 )

Definition at line 47 of file EvtItgSimpsonIntegrator.cc.

    : EvtItgAbsIntegrator( theFunction ), _precision( precision ), _maxLoop( maxLoop ) {}

~EvtItgSimpsonIntegrator()

EvtItgSimpsonIntegrator::~EvtItgSimpsonIntegrator ( )

virtual

Definition at line 55 of file EvtItgSimpsonIntegrator.cc.

{}

Member Function Documentation

evaluateIt()

double EvtItgSimpsonIntegrator::evaluateIt ( double lower, double higher ) const

protectedvirtual

Implements EvtItgAbsIntegrator.

Definition at line 57 of file EvtItgSimpsonIntegrator.cc.

                                                                              {
 
  // report(INFO,"EvtGen")<<"in evaluate"<<endl;
  int    j;
  double result( 0.0 );
  double s, st, ost( 0.0 );
  for ( j = 1; j < 4; j++ )
  {
    st  = trapezoid( lower, higher, j, result );
    s   = ( 4.0 * st - ost ) / 3.0;
    ost = st;
  }
 
  double olds( s );
  st = trapezoid( lower, higher, j, result );
  s  = ( 4.0 * st - ost ) / 3.0;
 
  if ( fabs( s - olds ) < _precision * fabs( olds ) || ( s == 0.0 && olds == 0.0 ) ) return s;
 
  ost = st;
 
  for ( j = 5; j < _maxLoop; j++ )
  {
 
    st = trapezoid( lower, higher, j, result );
    s  = ( 4.0 * st - ost ) / 3.0;
 
    if ( fabs( s - olds ) < _precision * fabs( olds ) || ( s == 0.0 && olds == 0.0 ) )
      return s;
    olds = s;
    ost  = st;
  }
 
  report( ERROR, "EvtGen" )
      << "Severe error in EvtItgSimpsonIntegrator.  Failed to converge after loop with 2**"
      << _maxLoop << " calls to the integrand in." << endl;
 
  return 0.0;
}

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

• EvtItgSimpsonIntegrator.hh
• EvtItgSimpsonIntegrator.cc