libs/qm-dsp/maths/Correlation.cpp

   1 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
   2
   3 /*
   4     QM DSP Library
   5
   6     Centre for Digital Music, Queen Mary, University of London.
   7     This file 2005-2006 Christian Landone.
   8
   9     This program is free software; you can redistribute it and/or
  10     modify it under the terms of the GNU General Public License as
  11     published by the Free Software Foundation; either version 2 of the
  12     License, or (at your option) any later version.  See the file
  13     COPYING included with this distribution for more information.
  14 */
  15
  16 #include "Correlation.h"
  17
  18 //////////////////////////////////////////////////////////////////////
  19 // Construction/Destruction
  20 //////////////////////////////////////////////////////////////////////
  21
  22 Correlation::Correlation()
  23 {
  24
  25 }
  26
  27 Correlation::~Correlation()
  28 {
  29
  30 }
  31
  32 void Correlation::doAutoUnBiased(double *src, double *dst, unsigned int length)
  33 {
  34     double tmp = 0.0;
  35     double outVal = 0.0;
  36
  37     unsigned int i,j;
  38
  39     for( i = 0; i <  length; i++)
  40     {
  41         for( j = i; j < length; j++)
  42         {
  43             tmp += src[ j-i ] * src[ j ];
  44         }
  45
  46
  47         outVal = tmp / ( length - i );
  48
  49         if( outVal <= 0 )
  50             dst[ i ] = EPS;
  51         else
  52             dst[ i ] = outVal;
  53
  54         tmp = 0.0;
  55     }
  56 }