SMS Class Reference

#include <SMS.h>

Public Types
enum	SMSType { None = 0, Interpolate = 1, Iterate = 2, Weighted = 4 }

Public Member Functions
GlobalPoint	location (const std::vector< GlobalPoint > &) const
GlobalPoint	location (const std::vector< std::pair< GlobalPoint, float > > &) const
	SMS (SMSType tp=(SMSType)(Interpolate|Iterate|Weighted), float q=0.5)

Private Attributes
float	theRatio
SMSType	theType

Detailed Description

Class to compute the SMS location estimator The SMS estimator is the mean value of a set of observations with Small Median of Squared distances.

Definition at line 16 of file SMS.h.

Member Enumeration Documentation

enum SMS::SMSType

Enumerator
None
Interpolate
Iterate
Weighted

Definition at line 19 of file SMS.h.

               { None        = 0,
                 Interpolate = 1,
                 Iterate     = 2,
                 Weighted    = 4 };

Constructor & Destructor Documentation

SMS::SMS	(	SMSType	tp = (SMSType) (Interpolate | Iterate | Weighted),
		float	q = 0.5
	)

Constructor.

Parameters

tp	What specific kind of SMS algorithm do you want?
q	What fraction of data points are considered for the "next step"?

Definition at line 73 of file SMS.cc.

: theType(tp) , theRatio(q) {}

Member Function Documentation

GlobalPoint SMS::location

(

const std::vector< GlobalPoint > &

data

)

const

Definition at line 76 of file SMS.cc.

References PDRates::average, gather_cfg::cout, i, Interpolate, Iterate, j, mag2(), theRatio, theType, tmp, and Weighted.

Referenced by SmsModeFinder3d::operator()().

{
  if ( theType & Weighted )
  {
    std::cout << "[SMS] warning: Weighted SMS was asked for, but data are "
              << "weightless!" << std::endl;
  };
  int nobs=data.size();
  int nq=(int) ceil( theRatio*nobs);
  // cout << "nobs= " << nobs << "  nq= " << nq << endl;

  // Compute distances
  std::vector<MyPair> pairs;

  for ( std::vector< GlobalPoint >::const_iterator i=data.begin(); i!=data.end() ; ++i )
  {
    std::vector < float > D;
    // Compute squared distances to all points
    for ( std::vector< GlobalPoint >::const_iterator j=data.begin(); j!=data.end() ; ++j )
    { D.push_back ( (*j - *i).mag2() ); }
    // Find q-quantile in each row of the distance matrix
    sort( D.begin(), D.end() );
    MyPair tmp (  D[nq-1], &(*i) );
    pairs.push_back ( tmp );
  };

  // Sort pairs by first element
  sort( pairs.begin(), pairs.end(), Sorter() );
  if ( !(theType & SMS::Interpolate) &&
       !(theType & SMS::Iterate) )
  {
    // we dont interpolate, we dont iterate, so we can stop right here.
    // cout << "No interpolation, no iteration" << endl;
    return *(pairs.begin()->second);
  };

  // we dont iterate, or we dont have anything to iterate (anymore?)
  // so we stop here

  // cout << "nobs= " << nobs << "  nq= " << nq << endl;
  if (!(theType & SMS::Iterate) || nq<=2)
    return average ( pairs, nq );

  // we iterate (recursively)

  std::vector < GlobalPoint > data1;
  std::vector<MyPair>::iterator j;

  for ( j=pairs.begin(); j-pairs.begin()<nq; ++j)
     data1.push_back(*(j->second));

  return this->location( data1 );

}

GlobalPoint SMS::location

(

const std::vector< std::pair< GlobalPoint, float > > &

)

const

Member Data Documentation

float SMS::theRatio

private

Definition at line 36 of file SMS.h.

Referenced by location().

SMSType SMS::theType

private

Definition at line 35 of file SMS.h.

Referenced by location().