qm-dsp  1.8
CosineDistance.cpp
Go to the documentation of this file.
00001 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
00002 
00003 /*
00004     QM DSP Library
00005 
00006     Centre for Digital Music, Queen Mary, University of London.
00007     This file copyright 2008 Kurt Jacobson.
00008 
00009     This program is free software; you can redistribute it and/or
00010     modify it under the terms of the GNU General Public License as
00011     published by the Free Software Foundation; either version 2 of the
00012     License, or (at your option) any later version.  See the file
00013     COPYING included with this distribution for more information.
00014 */
00015 
00016 #include "CosineDistance.h"
00017 
00018 #include <iostream>
00019 #include <limits>
00020 
00021 using std::cerr;
00022 
00023 double CosineDistance::distance(const vector<double> &v1,
00024                                 const vector<double> &v2)
00025 {
00026     dist = 1.0; dDenTot = 0; dDen1 = 0; dDen2 = 0; dSum1 =0;
00027     double small = 1e-20;
00028 
00029     //check if v1, v2 same size
00030     if (v1.size() != v2.size())
00031     {
00032         cerr << "CosineDistance::distance: ERROR: vectors not the same size\n";
00033         return 1.0;
00034     }
00035     else
00036     {
00037         for(int i=0; i<v1.size(); i++)
00038         {
00039             dSum1 += v1[i]*v2[i];
00040             dDen1 += v1[i]*v1[i];
00041             dDen2 += v2[i]*v2[i];
00042         }
00043         dDenTot = sqrt(fabs(dDen1*dDen2)) + small;
00044         dist = 1-((dSum1)/dDenTot);
00045         return dist;
00046     }
00047 }