C#或vb.net中的DBSCAN代码,用于Cluster Analysis

using System;
using System.Collections.Generic;
using System.Linq;

public class DBSCAN
{
    private readonly double eps;
    private readonly int minPts;

    public DBSCAN(double eps, int minPts)
    {
        this.eps = eps;
        this.minPts = minPts;
    }

    public List<Cluster> Run(IEnumerable<Point> points)
    {
        var clusters = new List<Cluster>();
        var visited = new HashSet<Point>();

        foreach (var point in points)
        {
            if (visited.Contains(point))
                continue;

            visited.Add(point);
            var neighbors = GetNeighbors(points, point);

            if (neighbors.Count < minPts)
            {
                // Noise point
                continue;
            }

            var cluster = new Cluster();
            ExpandCluster(points, visited, neighbors, cluster);
            clusters.Add(cluster);
        }

        return clusters;
    }

    private void ExpandCluster(IEnumerable<Point> points, HashSet<Point> visited, List<Point> neighbors, Cluster cluster)
    {
        foreach (var neighbor in neighbors)
        {
            if (!visited.Contains(neighbor))
            {
                visited.Add(neighbor);
                var neighborNeighbors = GetNeighbors(points, neighbor);

                if (neighborNeighbors.Count >= minPts)
                {
                    neighbors.AddRange(neighborNeighbors);
                }
            }

            if (!cluster.Points.Contains(neighbor))
            {
                cluster.Points.Add(neighbor);
            }
        }
    }

    private List<Point> GetNeighbors(IEnumerable<Point> points, Point point)
    {
        return points.Where(p => Distance(p, point) <= eps).ToList();
    }

    private double Distance(Point a, Point b)
    {
        return Math.Sqrt(Math.Pow(a.X - b.X, 2) + Math.Pow(a.Y - b.Y, 2));
    }
}

public class Point
{
    public double X { get; set; }
    public double Y { get; set; }
}

public class Cluster
{
    public List<Point> Points { get; set; } = new List<Point>();
}

Imports System
Imports System.Collections.Generic
Imports System.Linq

Public Class DBSCAN
    Private eps As Double
    Private minPts As Integer

    Public Sub New(eps As Double, minPts As Integer)
        Me.eps = eps
        Me.minPts = minPts
    End Sub

    Public Function Run(points As IEnumerable(Of Point)) As List(Of Cluster)
        Dim clusters As New List(Of Cluster)()
        Dim visited As New HashSet(Of Point)()

        For Each point In points
            If visited.Contains(point) Then Continue For

            visited.Add(point)
            Dim neighbors = GetNeighbors(points, point)

            If neighbors.Count < minPts Then
                ' Noise point
                Continue For
            End If

            Dim cluster As New Cluster()
            ExpandCluster(points, visited, neighbors, cluster)
            clusters.Add(cluster)
        Next

        Return clusters
    End Function

    Private Sub ExpandCluster(points As IEnumerable(Of Point), visited As HashSet(Of Point), neighbors As List(Of Point), cluster As Cluster)
        For Each neighbor In neighbors
            If Not visited.Contains(neighbor) Then
                visited.Add(neighbor)
                Dim neighborNeighbors = GetNeighbors(points, neighbor)

                If neighborNeighbors.Count >= minPts Then
                    neighbors.AddRange(neighborNeighbors)
                End If
            End If

            If Not cluster.Points.Contains(neighbor) Then
                cluster.Points.Add(neighbor)
            End If
        Next
    End Sub

    Private Function GetNeighbors(points As IEnumerable(Of Point), point As Point) As List(Of Point)
        Return points.Where(Function(p) Distance(p, point) <= eps).ToList()
    End Function

    Private Function Distance(a As Point, b As Point) As Double
        Return Math.Sqrt(Math.Pow(a.X - b.X, 2) + Math.Pow(a.Y - b.Y, 2))
    End Function
End Class

Public Class Point
    Public Property X As Double
    Public Property Y As Double
End Class

Public Class Cluster
    Public Property Points As New List(Of Point)()
End Class

// C# 示例
var points = new List<Point>
{
    new Point { X = 1, Y = 1 },
    new Point { X = 1, Y = 2 },
    new Point { X = 2, Y = 1 },
    new Point { X = 6, Y = 6 },
    new Point { X = 6, Y = 7 },
    new Point { X = 7, Y = 6 }
};

var dbscan = new DBSCAN(2, 2);
var clusters = dbscan.Run(points);

foreach (var cluster in clusters)
{
    Console.WriteLine($"Cluster with {cluster.Points.Count} points:");
    foreach (var point in cluster.Points)
    {
        Console.WriteLine($"({point.X}, {point.Y})");
    }
}

' VB.NET 示例
Dim points As New List(Of Point) From {
    New Point With {.X = 1, .Y = 1},
    New Point With {.X = 1, .Y = 2},
    New Point With {.X = 2, .Y = 1},
    New Point With {.X = 6, .Y = 6},
    New Point With {.X = 6, .Y = 7},
    New Point With {.X = 7, .Y = 6}
}

Dim dbscan As New DBSCAN(2, 2)
Dim clusters = dbscan.Run(points)

For Each cluster In clusters
    Console.WriteLine($"Cluster with {cluster.Points.Count} points:")
    For Each point In cluster.Points
        Console.WriteLine($"({point.X}, {point.Y})")
    Next
Next