How to use

MersenneTwister

in

smile.math.random

@Override
public void nextDoubles(double[] d) {
  int n = d.length;
  for (int i = 0; i < n; i++) {
    d[i] = nextDouble();
  }
}
 

/**
 * Returns a random integer.
 */
public int nextInt() {
  return twister.nextInt();
}

public long nextLong() {
  return twister.nextLong();
}

/**
 * Initialize with default random number generator engine.
 */
public Random() {
  real = new UniversalGenerator();
  twister = new MersenneTwister();
}

/**
 * Constructor.
 */
public MersenneTwister(int seed) {
  setSeed(seed);
}

@Override
public int nextInt(int n) {
  if (n <= 0) {
    throw new IllegalArgumentException("n must be positive");
  }
  // n is a power of 2
  if ((n & -n) == n) {
    return (int) ((n * (long) next(31)) >> 31);
  }
  int bits, val;
  do {
    bits = next(31);
    val = bits % n;
  } while (bits - val + (n - 1) < 0);
  
  return val;
}

/**
 * Initialize with given seed for default random number generator engine.
 */
public Random(long seed) {
  real = new UniversalGenerator(seed);
  twister = new MersenneTwister(seed);
}

@Override
public void setSeed(long seed) {
  setSeed((int) (seed % UniversalGenerator.BIG_PRIME));
}

@Nonnull
public static PRNG createPRNG(@Nonnull PRNGType type) {
  final PRNG rng;
  switch (type) {
    case java:
      rng = new JavaRandom();
      break;
    case secure:
      rng = new JavaRandom(new SecureRandom());
      break;
    case smile:
      rng = new SmileRandom();
      break;
    case smileMT:
      rng = new SmileRandom(new smile.math.random.MersenneTwister());
      break;
    case smileMT64:
      rng = new SmileRandom(new smile.math.random.MersenneTwister64());
      break;
    case commonsMath3MT:
      rng = new CommonsMathRandom(new org.apache.commons.math3.random.MersenneTwister());
      break;
    default:
      throw new IllegalStateException("Unexpected type: " + type);
  }
  return rng;
}

/**
 * Returns a random integer in [0, n).
 */
public int nextInt(int n) {
  return twister.nextInt(n);
}

/**
 * Constructor.
 */
public MersenneTwister(long seed) {
  setSeed(seed);
}

@Nonnull
public static PRNG createPRNG(@Nonnull PRNGType type, long seed) {
  final PRNG rng;
  switch (type) {
    case java:
      rng = new JavaRandom(seed);
      break;
    case secure:
      rng = new JavaRandom(new SecureRandom(Primitives.toBytes(seed)));
      break;
    case smile:
      rng = new SmileRandom(seed);
      break;
    case smileMT:
      rng = new SmileRandom(
        new smile.math.random.MersenneTwister(Primitives.hashCode(seed)));
      break;
    case smileMT64:
      rng = new SmileRandom(new smile.math.random.MersenneTwister64(seed));
      break;
    case commonsMath3MT:
      rng = new CommonsMathRandom(
        new org.apache.commons.math3.random.MersenneTwister(seed));
      break;
    default:
      throw new IllegalStateException("Unexpected type: " + type);
  }
  return rng;
}

  @Override
  public long nextLong() {
    long x = nextInt();
    return (x << 32) | nextInt();
  }
}

/**
 * Initialize the random generator with a seed.
 */
public void setSeed(long seed) {
  real.setSeed(seed);
  twister.setSeed(seed);
}

@Override
public int next(int numbits) {
  return nextInt() >>> (32 - numbits);
}
 

@Override
public double nextDouble() {
  return (nextInt() >>> 1) / (double) Integer.MAX_VALUE;
}