Xorshiftアルゴリズムを使用して乱数を発生させるクラスです 初期化処理とか正規乱数周りとか結構いい加減だったり

Xorshift.java

public class Xorshift
{
	private long[] seed;
	
	private double nextGaussian;
	private boolean hasNextGaussian;
	
	public Xorshift()
	{
		long l = System.currentTimeMillis();
		seed = new long[]{l, l, l, l};
		for(long i = System.nanoTime() % 1000; i != 0; i--)
		{
			next();
		}
	}
	
	public Xorshift(long... seed)
	{
		setSeed(seed);
	}
	
	public Xorshift setSeed(long seed)
	{
		this.seed = new long[]{seed, seed, seed, seed};
		return this;
	}
	
	public Xorshift setSeed(long... seed)
	{
		if(seed.length < 4)
		{
			return setSeed(seed[0]);
		}
		this.seed = seed;
		return this;
	}
	
	public long next()
	{
		long t = seed[0] ^ (seed[0] << 11);
		seed[0] = seed[1];
		seed[1] = seed[2];
		seed[2] = seed[3];
		seed[3] = (seed[3] ^ (seed[3] >> 19)) ^ (t ^ (t >> 8));
		return seed[3];
	}
	
	public long nextLong()
	{
		long l = this.next();
		if(this.nextBoolean())
		{
			l = ~l + 1L;
		}
		return l;
	}
	
	public int nextInt()
	{
		return (int)this.next();
	}
	
	public int nextInt(int i)
	{
		double r = this.nextDouble();
		r *= i;
		r = Math.floor(r);
		return (int)r;
	}
	
	public float nextFloat()
	{
		return (float)this.next() / Long.MAX_VALUE;
	}
	
	public double nextDouble()
	{
		return (double)this.next() / Long.MAX_VALUE;
	}
	
	private long temp;
	private int cnt = 0;
	
	public boolean nextBoolean()
	{
		if(cnt == 63)
		{
			temp = this.next();
			cnt = 0;
		}
		boolean b = ((temp >> cnt) & 1L) == 0;
		cnt += 1;
		return b;
	}
	
	public void nextBytes(byte[] b)
	{
		long tmp = nextLong();
		int count = 0;
		for(int i = 0; i < b.length; i++)
		{
			if(count == 8)
			{
				count = 0;
				tmp = nextLong();
			}
			b[i] = (byte)(tmp >>> (count << 3));
			count += 1;
		}
	}
	
	public double nextGaussian()
	{
		if(hasNextGaussian)
		{
			hasNextGaussian = false;
			return nextGaussian;
		}
		double x = Math.sqrt(-2D * Math.log(this.nextDouble()));
		double y = 2D * Math.PI * this.nextDouble();
		double z = x * Math.sin(y);
		nextGaussian = x * Math.cos(y);
		hasNextGaussian = true;
		return z;
	}
	
}