distance.h

Go to the documentation of this file.

 
 
#ifndef CHEBYSHEV_DISTANCE_H
#define CHEBYSHEV_DISTANCE_H
#include <cmath>
 
 
namespace chebyshev {
namespace prec {
 
    namespace distance {
 
 
        template<typename Type = real_t>
        inline prec_t absolute(Type a, Type b) {
            const Type diff = b - a;
            return prec_t(diff > Type(0.0) ? diff : -diff);
        }
 
 
        template<typename Vector>
        inline prec_t euclidean(const Vector& v1, const Vector& v2) {
 
            if (v1.size() != v2.size() || !v1.size())
                return get_nan();
 
            auto sum = (v1[0] - v2[0]) * (v1[0] - v2[0]);
            for (size_t i = 1; i < v1.size(); i++) {
                sum += (v1[i] - v2[i]) * (v1[i] - v2[i]);
            }
 
            return std::sqrt(sum);
        }
 
 
        inline unsigned int hamming(const std::string& a, const std::string& b) {
 
            unsigned int sum = 0;
            for (size_t i = 0; i < std::min(a.size(), b.size()); i++)
                if (a[i] != b[i])
                    sum++;
 
            if (a.size() != b.size())
                sum += std::abs(int(a.size()) - int(b.size()));
 
            return sum;
        }
 
    }
 
}}
 
#endif