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FastRandomRandomization.cs
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FastRandomRandomization.cs
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using System;
using System.Threading;
using SharpNeatLib.Maths;
namespace GeneticSharp
{
/// <summary>
/// An IRandomization using FastRandom has pseudo-number generator.
/// <see href="http://www.codeproject.com/Articles/9187/A-fast-equivalent-for-System-Random"/>
/// </summary>
public class FastRandomRandomization : RandomizationBase
{
private static readonly FastRandom _globalRandom = new FastRandom(DateTime.Now.Millisecond);
private static readonly object _globalLock = new object();
private static int? _seed;
/// <summary>
/// Random number generator
/// </summary>
private static ThreadLocal<FastRandom> _threadRandom = new ThreadLocal<FastRandom>(NewRandom);
/// <summary>
/// Creates a new instance of FastRandom. The seed is derived
/// from a global (static) instance of Random, rather
/// than time.
/// </summary>
private static FastRandom NewRandom()
{
lock (_globalLock)
{
return new FastRandom(_seed ?? _globalRandom.Next(0, int.MaxValue));
}
}
/// <summary>
/// Returns an instance of Random which can be used freely
/// within the current thread.
/// </summary>
private static FastRandom Instance { get { return _threadRandom.Value; } }
/// <summary>
/// Resets the pseudorandom number generator (SharpNeatLib.Maths.FastRandom) initial seed.
/// </summary>
/// <param name="seed">The seed. Use null to reset to default one.</param>
/// <remarks>
/// Can be useful on situation where you need to generate the same result with the same parameter.
/// </remarks>
public static void ResetSeed(int? seed)
{
_seed = seed;
_threadRandom = new ThreadLocal<FastRandom>(NewRandom);
}
/// <summary>
/// Gets an integer value between minimum value (inclusive) and maximum value (exclusive).
/// </summary>
/// <returns>The integer.</returns>
/// <param name="min">Minimum value (inclusive).</param>
/// <param name="max">Maximum value (exclusive).</param>
public override int GetInt(int min, int max)
{
return Instance.Next(min, max);
}
/// <summary>
/// Gets a float value between 0.0 and 1.0.
/// </summary>
/// <returns>
/// The float value.
/// </returns>
public override float GetFloat()
{
return (float)Instance.NextDouble();
}
/// <summary>
/// Gets a double value between 0.0 and 1.0.
/// </summary>
/// <returns>The double value.</returns>
public override double GetDouble()
{
return Instance.NextDouble();
}
}
}