KD_test.cs

using System;
using System.Linq;
using Accord.MachineLearning.Structures;

namespace KD_test {
    class Program {
        public static void Main() {
            double[][] points = {
                new double[] {5, 5, 4},
                new double[] {4, 7, 5},
                new double[] {7, 2, 9},
                new double[] {2, 3, 5},
                new double[] {8, 5, 1},
                new double[] {9, 6, 5},
            };

             double[][] values = {
                new double[] {0, 1, 0},
                new double[] {1, 7, 5},
                new double[] {7, 1, 9},
                new double[] {2, 3, 1},
                new double[] {8, 5, 1},
                new double[] {9, 0, 5},
            };

             var tree = KDTree.FromData( points, values );

            var newPosition = new double[] {5, 5, 5};
            var speedValue = tree.ApproximateNearest(newPosition, 1 ).Value; // 90% probabilety

            var speedAsString = speedValue.Aggregate("", (s, d) =>s + d + " ");
            Console.WriteLine( speedAsString );

            Console.ReadLine();
        }
    }
}