Chris@26: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@26: 
Chris@26: /*
Chris@26:     Vamp feature extraction plugin using the MATCH audio alignment
Chris@26:     algorithm.
Chris@26: 
Chris@26:     Centre for Digital Music, Queen Mary, University of London.
Chris@26:     This file copyright 2007 Simon Dixon, Chris Cannam and QMUL.
Chris@26:     
Chris@26:     This program is free software; you can redistribute it and/or
Chris@26:     modify it under the terms of the GNU General Public License as
Chris@26:     published by the Free Software Foundation; either version 2 of the
Chris@26:     License, or (at your option) any later version.  See the file
Chris@26:     COPYING included with this distribution for more information.
Chris@26: */
Chris@26: 
Chris@26: #include "DistanceMetric.h"
Chris@26: 
Chris@26: #include <cassert>
Chris@26: #include <cmath>
Chris@26: 
Chris@26: using std::vector;
Chris@26: 
Chris@26: double
Chris@26: DistanceMetric::calcDistance(const vector<double> &f1,
Chris@26: 			     const vector<double> &f2)
Chris@26: {
Chris@26:     double d = 0;
Chris@26:     double sum = 0;
Chris@26: 
Chris@26:     int featureSize = f1.size();
Chris@26:     assert(int(f2.size()) == featureSize);
Chris@26:     
Chris@26:     for (int i = 0; i < featureSize; i++) {
Chris@26:         d += fabs(f1[i] - f2[i]);
Chris@116:         sum += fabs(f1[i]) + fabs(f2[i]);
Chris@26:     }
Chris@26: 
Chris@26:     if (sum == 0)
Chris@26:         return 0;
Chris@26:     if (m_norm == NormaliseDistanceToSum)
Chris@26:         return d / sum; // 0 <= d/sum <= 2
Chris@26:     if (m_norm != NormaliseDistanceToLogSum)
Chris@26:         return d;
Chris@26: 
Chris@26:     // note if this were to be restored, it would have to use
Chris@26:     // totalEnergies vector instead of f1[freqMapSize] which used to
Chris@26:     // store the total energy:
Chris@26:     //	double weight = (5 + Math.log(f1[freqMapSize] + f2[freqMapSize]))/10.0;
Chris@26: 
Chris@26:     double weight = (8 + log(sum)) / 10.0;
Chris@26: 
Chris@26:     if (weight < 0) weight = 0;
Chris@26:     else if (weight > 1) weight = 1;
Chris@26: 
Chris@26:     return d / sum * weight;
Chris@26: }
Chris@26: