Examples of MersenneTwister

cern.jet.random.engine.MersenneTwister
fsu.edu/~geo/diehard.html">diehard test of G. Marsaglia and the load test of P. Hellekalek and S. Wegenkittl.
Performance: Its speed is comparable to other modern generators (in particular, as fast as java.util.Random.nextFloat()). 2.5 million calls to raw() per second (Pentium Pro 200 Mhz, JDK 1.2, NT). Be aware, however, that there is a non-negligible amount of overhead required to initialize the data structures used by a MersenneTwister. Code like
```
 double sum = 0.0; for (int i=0; i<100000; ++i) { RandomElement twister = new MersenneTwister(new java.util.Date()); sum += twister.raw(); } 
```
will be wildly inefficient. Consider using
```
 double sum = 0.0; RandomElement twister = new MersenneTwister(new java.util.Date()); for (int i=0; i<100000; ++i) { sum += twister.raw(); } 
```
instead. This allows the cost of constructing the MersenneTwister object to be borne only once, rather than once for each iteration in the loop.
Implementation: After M. Matsumoto and T. Nishimura, "Mersenne Twister: A 623-Dimensionally Equidistributed Uniform Pseudo-Random Number Generator", ACM Transactions on Modeling and Computer Simulation, Vol. 8, No. 1, January 1998, pp 3--30.
More info on Masumoto's homepage.
More info on Pseudo-random number generators is on the Web.
Yet some more info.
The correctness of this implementation has been verified against the published output sequence mt19937-2.out of the C-implementation mt19937-2.c. (Call test(1000) to print the sequence).
Note that this implementation is not synchronized.
Details: MersenneTwister is designed with consideration of the flaws of various existing generators in mind. It is an improved version of TT800, a very successful generator. MersenneTwister is based on linear recurrences modulo 2. Such generators are very fast, have extremely long periods, and appear quite robust. MersenneTwister produces 32-bit numbers, and every k-dimensional vector of such numbers appears the same number of times as k successive values over the period length, for each k <= 623 (except for the zero vector, which appears one time less). If one looks at only the first n <= 16 bits of each number, then the property holds for even larger k, as shown in the following table (taken from the publication cited above):

n

1

2

3

4

5

6

7

8

9

10

11

12 .. 16

17 .. 32

k

19937

9968

6240

4984

3738

3115

2493

2492

1869

1869

1248

1246

623

MersenneTwister generates random numbers in batches of 624 numbers at a time, so the caching and pipelining of modern systems is exploited. The generator is implemented to generate the output by using the fastest arithmetic operations only: 32-bit additions and bit operations (no division, no multiplication, no mod). These operations generate sequences of 32 random bits (int's). long's are formed by concatenating two 32 bit int's. float's are formed by dividing the interval [0.0,1.0] into 2³² sub intervals, then randomly choosing one subinterval. double's are formed by dividing the interval [0.0,1.0] into 2⁶⁴ sub intervals, then randomly choosing one subinterval.
@author wolfgang.hoschek@cern.ch @version 1.0, 09/24/99 @see java.util.Random
de.yaams.extensions.basemap.tiled.util.MersenneTwister
ath.keio.ac.jp/matumoto/emt.html
email: matumoto@math.keio.ac.jp
@author Makoto Matsumoto (matumoto@math.keio.ac.jp) @author Takuji Nishimura
freenet.support.math.MersenneTwister
This is a synchronized wrapper around {@link org.spaceroots.mantissa.random.MersenneTwister}which also adds additional {@code setSeed()} methods. @author infinity0
jmt.engine.random.engine.MersenneTwister
ath.keio.ac.jp/matumoto/emt.html
email: matumoto@math.keio.ac.jp

@author (translated in java by) Federico Granata

org.apache.commons.math.random.MersenneTwister

ath.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html"> http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html.

This generator is described in a paper by Makoto Matsumoto and Takuji Nishimura in 1998: Mersenne Twister: A 623-Dimensionally Equidistributed Uniform Pseudo-Random Number Generator, ACM Transactions on Modeling and Computer Simulation, Vol. 8, No. 1, January 1998, pp 3--30

This class is mainly a Java port of the 2002-01-26 version of the generator written in C by Makoto Matsumoto and Takuji Nishimura. Here is their original copyright:

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
The names of its contributors may not be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

@version $Revision: 990655 $ $Date: 2010-08-29 23:49:40 +0200 (dim. 29 août 2010) $ @since 2.0

org.apache.commons.math3.random.MersenneTwister

ath.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html"> http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html.

This class is mainly a Java port of the 2002-01-26 version of the generator written in C by Makoto Matsumoto and Takuji Nishimura. Here is their original copyright:

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
The names of its contributors may not be used to endorse or promote products derived from this software without specific prior written permission.

@since 2.0

org.apache.mahout.math.jet.random.engine.MersenneTwister
@deprecated until unit tests are in place. Until this time, this class/interface is unsupported.
org.jamesii.core.math.random.generators.mersennetwister.MersenneTwister
This class implements the Mersenne Twister pseudo-random number generator algorithm MT19937 as described by Matsumoto and Nishimura.
The Mersenne Twister is a very high-quality PRNG specifically suited for stochastic sampling and simulation. It has very high-order of dimensional equidistribution and passes even the Diehard tests. The period of this algorithm is 2¹⁹⁹³⁷ − 1, so repetition is pretty far away. That said it is also pretty fast in average, except for the first number to be generated and if the internal pool runs out. It is not recommend for cryptographic purposes! @author Johannes Rössel
tiled.util.MersenneTwister
ath.keio.ac.jp/matumoto/emt.html
email: matumoto@math.keio.ac.jp
@author Makoto Matsumoto (matumoto@math.keio.ac.jp) @author Takuji Nishimura

Examples of org.apache.commons.math3.random.MersenneTwister

    }


    @Before
    public void setUp() {
        generator = createConvexHullGenerator(false);
        random = new MersenneTwister(10);
    }

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Examples of org.apache.commons.math3.random.MersenneTwister

 *  - allow editing of the point set
 */
public class GeometryExample {


    public static List<Vector2D> createRandomPoints(int size) {
        RandomGenerator random = new MersenneTwister();


        // create the cloud container
        List<Vector2D> points = new ArrayList<Vector2D>(size);
        // fill the cloud with a random distribution of points
        for (int i = 0; i < size; i++) {
            points.add(new Vector2D(FastMath.round(random.nextDouble() * 400 + 100),
                    FastMath.round(random.nextDouble() * 400 + 100)));
        }
        
        return points;
    }

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Examples of org.apache.commons.math3.random.MersenneTwister

                                   new GammaDistribution(5, 1),
                                   new GammaDistribution(9, 0.5));
            container.add(comp, c);


            c.gridx++;
            RandomGenerator rng = new MersenneTwister(0);
            comp = createComponent("Levy", 0, 3,
                                   new String[] { "c=0.5", "c=1", "c=2", "c=4", "c=8" },
                                   new LevyDistribution(rng, 0, 0.5),
                                   new LevyDistribution(rng, 0, 1),
                                   new LevyDistribution(rng, 0, 2),

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Examples of org.apache.commons.math3.random.MersenneTwister

            generators.add(new Pair<String, RandomVectorGenerator>("Uncorrelated\nUniform(JDK)",
                    new UncorrelatedRandomVectorGenerator(2, new UniformRandomGenerator(new JDKRandomGenerator()))));
            generators.add(new Pair<String, RandomVectorGenerator>("Independent\nRandom(MT)", new RandomVectorGenerator() {


                RandomGenerator[] rngs = new RandomGenerator[] {
                    new MersenneTwister(0),
                    new MersenneTwister(1)
                };
                
                public double[] nextVector() {
                    final double[] vector = new double[2];
                    vector[0] = rngs[0].nextDouble();

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Examples of org.apache.mahout.math.jet.random.engine.MersenneTwister

      // Simply make a list (0,1,..N-1) and randomize it, seeded with "p".
      // Note that this is perhaps not what you want...
      for (int i = N; --i >= 0;) {
        permutation[i] = i;
      }
      Uniform gen = new Uniform(new MersenneTwister((int) p));
      for (int i = 0; i < N - 1; i++) {
        int random = gen.nextIntFromTo(i, N - 1);


        //swap(i, random)
        int tmp = permutation[random];

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Examples of org.apache.mahout.math.jet.random.engine.MersenneTwister

  /**
   * Constructs a uniform distribution with the given minimum and maximum, using a {@link
   * org.apache.mahout.math.jet.random.engine.MersenneTwister} seeded with the given seed.
   */
  public Uniform(double min, double max, int seed) {
    this(min, max, new MersenneTwister(seed));
  }

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Examples of org.apache.mahout.math.jet.random.engine.MersenneTwister

      fraction = 1;
    }


    // random generator seeded with current time
    if (randomGenerator == null) {
      randomGenerator = new MersenneTwister((int) System.currentTimeMillis());
    }


    int ncols = (int) Math.round(matrix.size() * fraction);
    int max = ncols;
    long[] selected = new long[max]; // sampler works on long's, not int's

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Examples of org.apache.mahout.math.jet.random.engine.MersenneTwister

      columnFraction = 1;
    }


    // random generator seeded with current time
    if (randomGenerator == null) {
      randomGenerator = new MersenneTwister((int) System.currentTimeMillis());
    }


    int nrows = (int) Math.round(matrix.rows() * rowFraction);
    int ncols = (int) Math.round(matrix.columns() * columnFraction);
    int max = Math.max(nrows, ncols);

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Examples of org.apache.mahout.math.jet.random.engine.MersenneTwister

      columnFraction = 1;
    }


    // random generator seeded with current time
    if (randomGenerator == null) {
      randomGenerator = new MersenneTwister((int) System.currentTimeMillis());
    }


    int nslices = (int) Math.round(matrix.slices() * sliceFraction);
    int nrows = (int) Math.round(matrix.rows() * rowFraction);
    int ncols = (int) Math.round(matrix.columns() * columnFraction);

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Examples of org.apache.mahout.math.jet.random.engine.MersenneTwister

   * org.apache.mahout.math.jet.random.AbstractDistribution} are function objects, because they implement the proper
   * interfaces. Thus, if you are not happy with the default, just pass your favourite random generator to function
   * evaluating methods.
   */
  public static UnaryFunction random() {
    return new MersenneTwister(new Date());
  }

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n	1	2	3	4	5	6	7	8	9	10	11	12 .. 16	17 .. 32
k	19937	9968	6240	4984	3738	3115	2493	2492	1869	1869	1248	1246	623