Generic Entropy Class
using System;
using System.Collections.Generic;
using System.Text;
public class EntropyEx<T>
{
private const double NaturalLogOfTwo = 0.69314718055994530941723212145818;
private readonly Dictionary<T, int> _histograpm = new Dictionary<T, int>();
private bool _histograpmStatus;
private readonly int _size;
public EntropyEx()
{
_histograpm.Clear();
_histograpmStatus = false;
_size = GetSize();
}
public double Entropy(string str)
{
var s = str.GetBytes(Encoding.Default);
var histograpmL = new Dictionary<byte, int>();
foreach (var c in s)
if (!histograpmL.ContainsKey(c))
histograpmL.Add(c, 1);
else
histograpmL[c] += 1;
var e = 0.0;
foreach (var v in histograpmL.Values)
{
if (v <= 0)
continue;
var r = v / (double)s.Length;
e -= r * (Math.Log(r) / NaturalLogOfTwo);
}
return e / 8 * 100.0;
}
public double Entropy(T[] s)
{
if (_histograpmStatus)
{
_histograpm.Clear();
_histograpmStatus = false;
}
foreach (var c in s)
if (!_histograpm.ContainsKey(c))
_histograpm.Add(c, 1);
else
_histograpm[c] += 1;
_histograpmStatus = true;
var e = 0.0;
foreach (var v in _histograpm.Values)
{
if (v <= 0)
continue;
var r = v / (double) s.Length;
e -= r * (Math.Log(r) / NaturalLogOfTwo);
}
return e / _size * 100.0;
}
private byte[] ConvertTypeByteArray(T[] ia)
{
switch (Type.GetTypeCode(typeof(T)))
{
case TypeCode.Boolean:
break;
case TypeCode.Char:
break;
case TypeCode.SByte:
break;
case TypeCode.Byte:
break;
case TypeCode.Int16:
break;
case TypeCode.UInt16:
break;
case TypeCode.Int32:
break;
case TypeCode.UInt32:
break;
case TypeCode.Single:
break;
case TypeCode.String:
break;
case TypeCode.Decimal:
break;
case TypeCode.Int64:
break;
case TypeCode.UInt64:
break;
case TypeCode.Double:
break;
case TypeCode.DateTime:
break;
default:
throw new ArgumentException("Type is not a valid primitive.");
}
return ia.GetBytes();
}
private int GetSize()
{
var size = 0;
switch (Type.GetTypeCode(typeof(T)))
{
case TypeCode.Boolean:
size = 1;
break;
case TypeCode.Char:
size = 16;
break;
case TypeCode.SByte:
size = 8;
break;
case TypeCode.Byte:
size = 8;
break;
case TypeCode.Int16:
size = 16;
break;
case TypeCode.UInt16:
size = 16;
break;
case TypeCode.Int32:
size = 32;
break;
case TypeCode.UInt32:
size = 32;
break;
case TypeCode.Single:
size = 32;
break;
case TypeCode.String:
size = 32;
break;
case TypeCode.Decimal:
size = 192;
break;
case TypeCode.Int64:
size = 64;
break;
case TypeCode.UInt64:
size = 64;
break;
case TypeCode.Double:
size = 64;
break;
case TypeCode.DateTime:
size = 64;
break;
default:
throw new ArgumentException("Type is not a valid primitive within this context.");
}
return size;
}
}