lib/fpa/Common/IncrementalMeanAndVariance.cxx

   1 // =========================================================================
   2 // @author Leonardo Florez Valencia
   3 // @email florez-l@javeriana.edu.co
   4 // =========================================================================
   5 #include <fpa/Common/IncrementalMeanAndVariance.h>
   6 #include <cmath>
   7
   8 // -------------------------------------------------------------------------
   9 fpa::Common::IncrementalMeanAndVariance::
  10 IncrementalMeanAndVariance( )
  11 {
  12   this->Clear( );
  13 }
  14
  15 // -------------------------------------------------------------------------
  16 fpa::Common::IncrementalMeanAndVariance::
  17 ~IncrementalMeanAndVariance( )
  18 {
  19 }
  20
  21 // -------------------------------------------------------------------------
  22 double fpa::Common::IncrementalMeanAndVariance::
  23 GetMean( ) const
  24 {
  25   return( this->m_M );
  26 }
  27
  28 // -------------------------------------------------------------------------
  29 double fpa::Common::IncrementalMeanAndVariance::
  30 GetVariance( ) const
  31 {
  32   return( this->m_V );
  33 }
  34
  35 // -------------------------------------------------------------------------
  36 double fpa::Common::IncrementalMeanAndVariance::
  37 GetDeviation( ) const
  38 {
  39   return( std::sqrt( this->m_V ) );
  40 }
  41
  42 // -------------------------------------------------------------------------
  43 unsigned long fpa::Common::IncrementalMeanAndVariance::
  44 GetNumberOfSamples( ) const
  45 {
  46   return( ( unsigned long )( this->m_N ) );
  47 }
  48
  49 // -------------------------------------------------------------------------
  50 void fpa::Common::IncrementalMeanAndVariance::
  51 Clear( )
  52 {
  53   this->m_M = double( 0 );
  54   this->m_V = double( 0 );
  55   this->m_N = double( 0 );
  56 }
  57
  58 // -------------------------------------------------------------------------
  59 void fpa::Common::IncrementalMeanAndVariance::
  60 AddValue( double v )
  61 {
  62   this->m_N += double( 1 );
  63   double d = v - this->m_M;
  64   if( this->m_N > double( 1 ) )
  65   {
  66     double o = ( this->m_N - double( 2 ) ) / ( this->m_N - double( 1 ) );
  67     this->m_V = ( o * this->m_V ) + ( ( d * d ) / this->m_N );
  68   }
  69   else
  70     this->m_V = double( 0 );
  71   this->m_M += d / this->m_N;
  72 }
  73
  74 // eof - $RCSfile$