SimilarityFunctions.hpp

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/* 
 * SimilarityFunctions.hpp 
 *
 * This file is part of the Chemical Data Processing Toolkit
 *
 * Copyright (C) 2003 Thomas Seidel <thomas.seidel@univie.ac.at>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; see the file COPYING. If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 
#ifndef CDPL_DESCR_SIMILARITYFUNCTIONS_HPP
#define CDPL_DESCR_SIMILARITYFUNCTIONS_HPP
 
#include <cstddef>
#include <cmath>
 
#include "CDPL/Descr/APIPrefix.hpp"
#include "CDPL/Util/BitSet.hpp"
#include "CDPL/Math/VectorExpression.hpp"
 
 
namespace CDPL
{
 
    namespace Descr
    {
      
        CDPL_DESCR_API double calcTanimotoSimilarity(const Util::BitSet& bs1, const Util::BitSet& bs2);
 
        template <typename V>
        inline double calcTanimotoSimilarity(const V& v1, const V& v2);
 
        CDPL_DESCR_API double calcCosineSimilarity(const Util::BitSet& bs1, const Util::BitSet& bs2);
 
        template <typename V>
        inline double calcCosineSimilarity(const V& v1, const V& v2);
        
        CDPL_DESCR_API double calcEuclideanSimilarity(const Util::BitSet& bs1, const Util::BitSet& bs2);
 
        CDPL_DESCR_API double calcManhattanSimilarity(const Util::BitSet& bs1, const Util::BitSet& bs2);
 
        CDPL_DESCR_API double calcDiceSimilarity(const Util::BitSet& bs1, const Util::BitSet& bs2);
 
        CDPL_DESCR_API double calcTverskySimilarity(const Util::BitSet& bs1, const Util::BitSet& bs2, double a, double b);
 
        CDPL_DESCR_API std::size_t calcHammingDistance(const Util::BitSet& bs1, const Util::BitSet& bs2);
 
        template <typename V>
        inline double calcManhattanDistance(const V& v1, const V& v2);
        
        CDPL_DESCR_API double calcEuclideanDistance(const Util::BitSet& bs1, const Util::BitSet& bs2);
 
        template <typename V>
        inline double calcEuclideanDistance(const V& v1, const V& v2);
        
    } // namespace Descr
} // namespace CDPL
 
 
// Implementation
 
template <typename V>
inline double CDPL::Descr::calcTanimotoSimilarity(const V& v1, const V& v2)
{
    double ep12 = innerProd(v1, v2);
 
    return (ep12 / (innerProd(v1, v1) + innerProd(v2, v2) - ep12));
}
 
template <typename V>
inline double CDPL::Descr::calcCosineSimilarity(const V& v1, const V& v2)
{
    return angleCos(v1, v2, double(norm2(v1) * norm2(v2)));
}
 
template <typename V>
inline double CDPL::Descr::calcManhattanDistance(const V& v1, const V& v2)
{
    return norm1(v1 - v2);
}
 
template <typename V>
inline double CDPL::Descr::calcEuclideanDistance(const V& v1, const V& v2)
{
    auto dv = v1 - v2;
    
    return std::sqrt(double(innerProd(dv, dv)));
}
 
#endif // CDPL_DESCR_SIMILARITYFUNCTIONS_HPP