distance_point_point.h

// Description: Distance between two points

#ifndef PASTELGEOMETRY_DISTANCE_POINT_POINT_H
#define PASTELGEOMETRY_DISTANCE_POINT_POINT_H

#include "pastel/math/normbijection/normbijection_concept.h"
#include "pastel/sys/point/point_concept.h"

// Template defaults

#include "pastel/math/normbijection/euclidean_normbijection.h"
#include "pastel/sys/indicator/all_indicator.h"

namespace Pastel
{

    //! Computes the norm-bijection distance between points.
    template <
        typename A_Point,
        typename B_Point, 
        // We need to use Point_Real_F instead of Point_Real to
        // avoid a bug in Visual Studio 2015 Update 1.
        typename Real = typename Point_Real_F<A_Point, B_Point>::type,
        typename... ArgumentSet,
        Requires<
            Models<A_Point, Point_Concept>,
            Models<B_Point, Point_Concept>
        > = 0>
    Real distance2(
        const A_Point& aPoint,
        const B_Point& bPoint,
        ArgumentSet&&... argumentSet)
    {
        auto&& normBijection = 
            PASTEL_ARG(
                normBijection, 
                [](){return Euclidean_NormBijection<Real>();},
                [](auto input) {return implicitArgument(Models<decltype(input), NormBijection_Concept>());}
            );

        auto&& keepGoing = 
            PASTEL_ARG(
                keepGoing, 
                []() {return allIndicator();},
                [](auto input) {return Models<decltype(input), Indicator_Concept(Real)>();}
            );

        PENSURE_OP(dimension(aPoint), ==, dimension(bPoint));

        Real result = 0;

        integer n = dimension(aPoint);
        for (integer i = 0;i < n && keepGoing(result);++i)
        {
            result = normBijection.addAxis(result, 
                normBijection.signedAxis(
                    pointAxis(bPoint, i) - pointAxis(aPoint, i)));
        }

        return result;
    }

}

#endif