Algorithms/LinearAlgebra/Distances/Manhattan.cs

using System;
using System.Linq;

namespace Algorithms.LinearAlgebra.Distances;

//github.com/ <summary>
//github.com/ Implementation fo Manhattan distance.
//github.com/ It is the sum of the lengths of the projections of the line segment between the points onto the coordinate axes.
//github.com/ In other words, it is the sum of absolute difference between the measures in all dimensions of two points.
//github.com/
//github.com/ Its commonly used in regression analysis.
//github.com/ </summary>
public static class Manhattan
{
    //github.com/ <summary>
    //github.com/ Calculate Manhattan distance for two N-Dimensional points.
    //github.com/ </summary>
    //github.com/ <param name="point1">First N-Dimensional point.</param>
    //github.com/ <param name="point2">Second N-Dimensional point.</param>
    //github.com/ <returns>Calculated Manhattan distance.</returns>
    public static double Distance(double[] point1, double[] point2)
    {
        if (point1.Length != point2.Length)
        {
            throw new ArgumentException("Both points should have the same dimensionality");
        }

        // distance = |x1-y1| + |x2-y2| + ... + |xn-yn|
        return point1.Zip(point2, (x1, x2) => Math.Abs(x1 - x2)).Sum();
    }
}