Examples of com.orientechnologies.common.util.MersenneTwisterFast

Package com.orientechnologies.common.util

Examples of com.orientechnologies.common.util.MersenneTwisterFast

com.orientechnologies.common.util.MersenneTwisterFast
ath.keio.ac.jp/matumoto/emt.html"> The Mersenne Twister Home Page, with the initialization improved using the new 2002/1/26 initialization algorithm By Sean Luke, October 2004.
MersenneTwister is a drop-in subclass replacement for java.util.Random. It is properly synchronized and can be used in a multithreaded environment. On modern VMs such as HotSpot, it is approximately 1/3 slower than java.util.Random.
MersenneTwisterFast is not a subclass of java.util.Random. It has the same public methods as Random does, however, and it is algorithmically identical to MersenneTwister. MersenneTwisterFast has hard-code inlined all of its methods directly, and made all of them final (well, the ones of consequence anyway). Further, these methods are not synchronized, so the same MersenneTwisterFast instance cannot be shared by multiple threads. But all this helps MersenneTwisterFast achieve well over twice the speed of MersenneTwister. java.util.Random is about 1/3 slower than MersenneTwisterFast.
About the Mersenne Twister

This is a Java version of the C-program for MT19937: Integer version. The MT19937 algorithm was created by Makoto Matsumoto and Takuji Nishimura, who ask: "When you use this, send an email to: matumoto@math.keio.ac.jp with an appropriate reference to your work". Indicate that this is a translation of their algorithm into Java.
Reference. Makato Matsumoto and Takuji 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.
About this Version

Changes since V16: Added nextDouble(includeZero, includeOne) and nextFloat(includeZero, includeOne) to allow for half-open, fully-closed, and fully-open intervals.
Changes Since V15: Added serialVersionUID to quiet compiler warnings from Sun's overly verbose compilers as of JDK 1.5.
Changes Since V14: made strictfp, with StrictMath.log and StrictMath.sqrt in nextGaussian instead of Math.log and Math.sqrt. This is largely just to be safe, as it presently makes no difference in the speed, correctness, or results of the algorithm.
Changes Since V13: clone() method CloneNotSupportedException removed.
Changes Since V12: clone() method added.
Changes Since V11: stateEquals(...) method added. MersenneTwisterFast is equal to other MersenneTwisterFasts with identical state; likewise MersenneTwister is equal to other MersenneTwister with identical state. This isn't equals(...) because that requires a contract of immutability to compare by value.
Changes Since V10: A documentation error suggested that setSeed(int[]) required an int[] array 624 long. In fact, the array can be any non-zero length. The new version also checks for this fact.
Changes Since V9: readState(stream) and writeState(stream) provided.
Changes Since V8: setSeed(int) was only using the first 28 bits of the seed; it should have been 32 bits. For small-number seeds the behavior is identical.
Changes Since V7: A documentation error in MersenneTwisterFast (but not MersenneTwister) stated that nextDouble selects uniformly from the full-open interval [0,1]. It does not. nextDouble's contract is identical across MersenneTwisterFast, MersenneTwister, and java.util.Random, namely, selection in the half-open interval [0,1). That is, 1.0 should not be returned. A similar contract exists in nextFloat.
Changes Since V6: License has changed from LGPL to BSD. New timing information to compare against java.util.Random. Recent versions of HotSpot have helped Random increase in speed to the point where it is faster than MersenneTwister but slower than MersenneTwisterFast (which should be the case, as it's a less complex algorithm but is synchronized).
Changes Since V5: New empty constructor made to work the same as java.util.Random -- namely, it seeds based on the current time in milliseconds.
Changes Since V4: New initialization algorithms. See (see http://www.math.keio.ac.jp/matumoto/MT2002/emt19937ar.html)
The MersenneTwister code is based on standard MT19937 C/C++ code by Takuji Nishimura, with suggestions from Topher Cooper and Marc Rieffel, July 1997. The code was originally translated into Java by Michael Lecuyer, January 1999, and the original code is Copyright (c) 1999 by Michael Lecuyer.
Java notes

This implementation implements the bug fixes made in Java 1.2's version of Random, which means it can be used with earlier versions of Java. See the JDK 1.2 java.util.Random documentation for further documentation on the random-number generation contracts made. Additionally, there's an undocumented bug in the JDK java.util.Random.nextBytes() method, which this code fixes.
Just like java.util.Random, this generator accepts a long seed but doesn't use all of it. java.util.Random uses 48 bits. The Mersenne Twister instead uses 32 bits (int size). So it's best if your seed does not exceed the int range.
MersenneTwister can be used reliably on JDK version 1.1.5 or above. Earlier Java versions have serious bugs in java.util.Random; only MersenneTwisterFast (and not MersenneTwister nor java.util.Random) should be used with them.
License
Copyright (c) 2003 by Sean Luke.
Portions copyright (c) 1993 by Michael Lecuyer.
All rights reserved.

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.
- Neither the name of the copyright owners, their employers, nor the names of its contributors may 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 OWNERS 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 17

      ORecordVersion recordVersion = OVersionFactory.instance().createVersion();
      recordVersion.increment();
      recordVersion.increment();


      final byte[] bigChunk = new byte[OClusterPage.MAX_ENTRY_SIZE / 2];
      final MersenneTwisterFast mersenneTwisterFast = new MersenneTwisterFast();
      mersenneTwisterFast.nextBytes(bigChunk);


      int position = localPage.appendRecord(recordVersion, bigChunk, false);
      Assert.assertEquals(position, 0);
      Assert.assertEquals(localPage.getRecordVersion(0), recordVersion);

View Full Code Here

    ODirectMemoryPointer pagePointer = new ODirectMemoryPointer(new byte[OClusterPage.PAGE_SIZE + ODurablePage.PAGE_PADDING]);
    OCachePointer cachePointer = new OCachePointer(pagePointer, new OLogSequenceNumber(0, 0));
    cachePointer.incrementReferrer();


    OCacheEntry cacheEntry = new OCacheEntry(0, 0, cachePointer, false);
    final MersenneTwisterFast mersenneTwister = new MersenneTwisterFast();
    try {
      OClusterPage localPage = new OClusterPage(cacheEntry, true, ODurablePage.TrackMode.FULL);


      Set<Integer> positions = new HashSet<Integer>();


      int lastPosition;
      byte counter = 0;
      int freeSpace = localPage.getFreeSpace();


      ORecordVersion recordVersion = OVersionFactory.instance().createVersion();
      recordVersion.increment();


      do {
        lastPosition = localPage.appendRecord(recordVersion, new byte[] { counter, counter, counter }, false);
        if (lastPosition >= 0) {
          Assert.assertEquals(lastPosition, positions.size());
          positions.add(lastPosition);
          counter++;


          Assert.assertEquals(localPage.getFreeSpace(), freeSpace - (19 + OVersionFactory.instance().getVersionSize()));
          freeSpace = localPage.getFreeSpace();
        }
      } while (lastPosition >= 0);


      int filledRecordsCount = positions.size();
      Assert.assertEquals(localPage.getRecordsCount(), filledRecordsCount);


      for (int i = 0; i < filledRecordsCount; i++) {
        if (mersenneTwister.nextBoolean()) {
          localPage.deleteRecord(i);
          positions.remove(i);
        }
      }

View Full Code Here

    ODirectMemoryPointer pagePointer = new ODirectMemoryPointer(new byte[OClusterPage.PAGE_SIZE + ODurablePage.PAGE_PADDING]);
    OCachePointer cachePointer = new OCachePointer(pagePointer, new OLogSequenceNumber(0, 0));
    cachePointer.incrementReferrer();


    OCacheEntry cacheEntry = new OCacheEntry(0, 0, cachePointer, false);
    final MersenneTwisterFast mersenneTwister = new MersenneTwisterFast();
    try {
      OClusterPage localPage = new OClusterPage(cacheEntry, true, ODurablePage.TrackMode.FULL);


      Set<Integer> positions = new HashSet<Integer>();


      int lastPosition;
      byte counter = 0;
      int freeSpace = localPage.getFreeSpace();


      ORecordVersion recordVersion = OVersionFactory.instance().createVersion();
      recordVersion.increment();


      do {
        lastPosition = localPage.appendRecord(recordVersion, new byte[] { counter, counter, counter }, false);
        if (lastPosition >= 0) {
          Assert.assertEquals(lastPosition, positions.size());
          positions.add(lastPosition);
          counter++;


          Assert.assertEquals(localPage.getFreeSpace(), freeSpace - (19 + OVersionFactory.instance().getVersionSize()));
          freeSpace = localPage.getFreeSpace();
        }
      } while (lastPosition >= 0);


      int filledRecordsCount = positions.size();
      Assert.assertEquals(localPage.getRecordsCount(), filledRecordsCount);


      for (int i = 0; i < filledRecordsCount; i++) {
        if (mersenneTwister.nextBoolean()) {
          localPage.deleteRecord(i);
          positions.remove(i);
        }
      }

View Full Code Here

    Assert.assertEquals(rawBuffer.recordType, 1);
  }


  public void testAddOneBigRecord() throws IOException {
    byte[] bigRecord = new byte[2 * 65536 + 100];
    MersenneTwisterFast mersenneTwisterFast = new MersenneTwisterFast();
    mersenneTwisterFast.nextBytes(bigRecord);


    ORecordVersion recordVersion = OVersionFactory.instance().createVersion();
    recordVersion.increment();
    recordVersion.increment();

View Full Code Here


  }


  public void testKeyPutRandomUniform() throws Exception {
    final NavigableSet<Integer> keys = new TreeSet<Integer>();
    final MersenneTwisterFast random = new MersenneTwisterFast();


    while (keys.size() < KEYS_COUNT) {
      int key = random.nextInt(Integer.MAX_VALUE);
      sbTree.put(key, new ORecordId(key % 32000, OClusterPositionFactory.INSTANCE.valueOf(key)));
      keys.add(key);


      Assert.assertEquals(sbTree.get(key), new ORecordId(key % 32000, OClusterPositionFactory.INSTANCE.valueOf(key)));
    }

View Full Code Here


  public void testAddManySmallRecords() throws IOException {
    final int records = 10000;


    long seed = System.currentTimeMillis();
    MersenneTwisterFast mersenneTwisterFast = new MersenneTwisterFast(seed);
    System.out.println("testAddManySmallRecords seed : " + seed);


    Map<OClusterPosition, byte[]> positionRecordMap = new HashMap<OClusterPosition, byte[]>();


    ORecordVersion recordVersion = OVersionFactory.instance().createVersion();
    recordVersion.increment();
    recordVersion.increment();


    for (int i = 0; i < records; i++) {
      int recordSize = mersenneTwisterFast.nextInt(OClusterPage.MAX_RECORD_SIZE - 1) + 1;
      byte[] smallRecord = new byte[recordSize];
      mersenneTwisterFast.nextBytes(smallRecord);


      final OPhysicalPosition physicalPosition = paginatedCluster.createRecord(smallRecord, recordVersion, (byte) 2);


      positionRecordMap.put(physicalPosition.clusterPosition, smallRecord);
    }

View Full Code Here

    NavigableSet<Integer> keys = new TreeSet<Integer>();
    long seed = System.currentTimeMillis();


    System.out.println("testKeyPutRandomGaussian seed : " + seed);


    MersenneTwisterFast random = new MersenneTwisterFast(seed);


    while (keys.size() < KEYS_COUNT) {
      int key = generateGaussianKey(mx, dx, random);


      sbTree.put(key, new ORecordId(key % 32000, OClusterPositionFactory.INSTANCE.valueOf(key)));

View Full Code Here

    NavigableSet<Integer> keys = new TreeSet<Integer>();


    long seed = System.currentTimeMillis();


    System.out.println("testKeyDeleteRandomGaussian seed : " + seed);
    MersenneTwisterFast random = new MersenneTwisterFast(seed);


    while (keys.size() < KEYS_COUNT) {
      int key = generateGaussianKey(mx, dx, random);


      sbTree.put(key, new ORecordId(key % 32000, OClusterPositionFactory.INSTANCE.valueOf(key)));

View Full Code Here


  public void testAddManyBigRecords() throws IOException {
    final int records = 5000;


    long seed = System.currentTimeMillis();
    MersenneTwisterFast mersenneTwisterFast = new MersenneTwisterFast(seed);


    System.out.println("testAddManyBigRecords seed : " + seed);


    Map<OClusterPosition, byte[]> positionRecordMap = new HashMap<OClusterPosition, byte[]>();


    ORecordVersion recordVersion = OVersionFactory.instance().createVersion();
    recordVersion.increment();
    recordVersion.increment();


    for (int i = 0; i < records; i++) {
      int recordSize = mersenneTwisterFast.nextInt(2 * OClusterPage.MAX_RECORD_SIZE) + OClusterPage.MAX_RECORD_SIZE + 1;
      byte[] bigRecord = new byte[recordSize];
      mersenneTwisterFast.nextBytes(bigRecord);


      final OPhysicalPosition physicalPosition = paginatedCluster.createRecord(bigRecord, recordVersion, (byte) 2);


      positionRecordMap.put(physicalPosition.clusterPosition, bigRecord);
    }

View Full Code Here

    }
  }


  public void testValuesMajor() {
    NavigableMap<Integer, ORID> keyValues = new TreeMap<Integer, ORID>();
    MersenneTwisterFast random = new MersenneTwisterFast();


    while (keyValues.size() < KEYS_COUNT) {
      int key = random.nextInt(Integer.MAX_VALUE);


      sbTree.put(key, new ORecordId(key % 32000, OClusterPositionFactory.INSTANCE.valueOf(key)));
      keyValues.put(key, new ORecordId(key % 32000, OClusterPositionFactory.INSTANCE.valueOf(key)));
    }

View Full Code Here

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Examples of com.orientechnologies.common.util.MersenneTwisterFast

About the Mersenne Twister

About this Version

Java notes

License

Related Classes of com.orientechnologies.common.util.MersenneTwisterFast