jube-fork/Accord.MachineLearning/Collections/NodeDistance.cs

// Accord Machine Learning Library
// The Accord.NET Framework
// http://accord-framework.net
//
// Copyright © César Souza, 2009-2017
// cesarsouza at gmail.com
//
//    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 2.1 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; if not, write to the Free Software
//    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
//

namespace Accord.Collections
{
    using System;
    using System.Text;
    using Accord.Compat;

    /// <summary>
    ///   Node-distance pair.
    /// </summary>
    /// 
    /// <typeparam name="TNode">The class type for the nodes of the tree.</typeparam>
    /// 
    [Serializable]
    public struct NodeDistance<TNode> : IComparable<NodeDistance<TNode>>, IEquatable<NodeDistance<TNode>>
        where TNode : IEquatable<TNode>
    {
        private TNode node;
        private double distance;

        /// <summary>
        ///   Gets the node in this pair.
        /// </summary>
        /// 
        public TNode Node
        {
            get { return node; }
        }

        /// <summary>
        ///   Gets the distance of the node from the query point.
        /// </summary>
        /// 
        public double Distance
        {
            get { return distance; }
        }

        /// <summary>
        ///   Creates a new <see cref="NodeDistance&lt;T&gt;"/>.
        /// </summary>
        /// 
        /// <param name="node">The node value.</param>
        /// <param name="distance">The distance value.</param>
        /// 
        public NodeDistance(TNode node, double distance)
        {
            this.node = node;
            this.distance = distance;
        }

        /// <summary>
        ///   Determines whether the specified <see cref="System.Object"/>
        ///   is equal to this instance.
        /// </summary>
        /// 
        /// <param name="obj">The <see cref="System.Object"/> to compare
        ///   with this instance.</param>
        /// 
        /// <returns>
        ///   <c>true</c> if the specified <see cref="System.Object"/> is 
        ///   equal to this instance; otherwise, <c>false</c>.
        /// </returns>
        /// 
        public override bool Equals(object obj)
        {
            if (obj is NodeDistance<TNode>)
            {
                var b = (NodeDistance<TNode>)obj;
                return this.node.Equals(b.node) && this.distance == b.distance;
            }

            return false;
        }

        /// <summary>
        ///   Returns a hash code for this instance.
        /// </summary>
        /// 
        /// <returns>
        ///   A hash code for this instance, suitable for use in hashing
        ///   algorithms and data structures like a hash table. 
        /// </returns>
        /// 
        public override int GetHashCode()
        {
            int hash = 17;
            hash = hash * 23 + node.GetHashCode();
            hash = hash * 23 + distance.GetHashCode();
            return hash;
        }

        /// <summary>
        ///   Implements the equality operator.
        /// </summary>
        /// 
        public static bool operator ==(NodeDistance<TNode> a, NodeDistance<TNode> b)
        {
            return a.node.Equals(b.node) && a.distance == b.distance;
        }

        /// <summary>
        ///   Implements the inequality operator.
        /// </summary>
        /// 
        public static bool operator !=(NodeDistance<TNode> a, NodeDistance<TNode> b)
        {
            return !a.node.Equals(b.node) || a.distance != b.distance;
        }

        /// <summary>
        ///   Implements the lesser than operator.
        /// </summary>
        /// 
        public static bool operator <(NodeDistance<TNode> a, NodeDistance<TNode> b)
        {
            return a.distance < b.distance;
        }

        /// <summary>
        ///   Implements the greater than operator.
        /// </summary>
        /// 
        public static bool operator >(NodeDistance<TNode> a, NodeDistance<TNode> b)
        {
            return a.distance > b.distance;
        }

        /// <summary>
        ///   Determines whether the specified <see cref="NodeDistance{T}"/>
        ///   is equal to this instance.
        /// </summary>
        /// 
        /// <param name="other">The <see cref="NodeDistance{T}"/> to compare
        ///   with this instance.</param>
        /// 
        /// <returns>
        ///   <c>true</c> if the specified <see cref="NodeDistance{T}"/> is 
        ///   equal to this instance; otherwise, <c>false</c>.
        /// </returns>
        /// 
        public bool Equals(NodeDistance<TNode> other)
        {
            return distance == other.distance && node.Equals(other.node);
        }

        /// <summary>
        ///   Compares this instance to another node, returning an integer
        ///   indicating whether this instance has a distance that is less
        ///   than, equal to, or greater than the other node's distance.
        /// </summary>
        /// 
        public int CompareTo(NodeDistance<TNode> other)
        {
            return distance.CompareTo(other.distance);
        }

        /// <summary>
        ///   Compares this instance to another node, returning an integer
        ///   indicating whether this instance has a distance that is less
        ///   than, equal to, or greater than the other node's distance.
        /// </summary>
        /// 
        public int CompareTo(object obj)
        {
            return CompareTo((NodeDistance<TNode>)obj);
        }

        /// <summary>
        /// Returns a <see cref="System.String" /> that represents this instance.
        /// </summary>
        /// <returns>
        /// A <see cref="System.String" /> that represents this instance.
        /// </returns>
        public override string ToString()
        {
            return String.Format("<{0}, {1}>", node, distance);
        }
    }
}