Examples of java.util.Random.nextDouble()

java.util.Random.nextDouble()
Returns the next pseudorandom, uniformly distributed {@code double} value between {@code 0.0} and{@code 1.0} from this random number generator's sequence.
The general contract of {@code nextDouble} is that one{@code double} value, chosen (approximately) uniformly from therange {@code 0.0d} (inclusive) to {@code 1.0d} (exclusive), ispseudorandomly generated and returned.
The method {@code nextDouble} is implemented by class {@code Random}as if by:
```
  {@code}public double nextDouble()  return (((long)next(26) << 27) + next(27)) / (double)(1L << 53); }}
```
The hedge "approximately" is used in the foregoing description only because the {@code next} method is only approximately an unbiasedsource of independently chosen bits. If it were a perfect source of randomly chosen bits, then the algorithm shown would choose {@code double} values from the stated range with perfect uniformity.
[In early versions of Java, the result was incorrectly calculated as:
```
  {@code return (((long)next(27) << 27) + next(27)) / (double)(1L << 54);}
```
This might seem to be equivalent, if not better, but in fact it introduced a large nonuniformity because of the bias in the rounding of floating-point numbers: it was three times as likely that the low-order bit of the significand would be 0 than that it would be 1! This nonuniformity probably doesn't matter much in practice, but we strive for perfection.] @return the next pseudorandom, uniformly distributed {@code double}value between {@code 0.0} and {@code 1.0} from thisrandom number generator's sequence @see Math#random

    Stopwatch.p();
    SparseMatrix A = Matrix.sparse(4000, 10000);
    Random rand = new Random(1);
    for (int i = 0; i < A.rowCount(); i++) {
      for (int j = 0; j < A.columnCount(); j++) {
        if (rand.nextDouble() > 0.2) continue;
        A.put(i, j, rand.nextDouble() * 23);
      }
    }
    SingularValues singular = new SingularValues(A, 10).decompose();
    Stopwatch.p();

View Full Code Here

    SparseMatrix A = Matrix.sparse(4000, 10000);
    Random rand = new Random(1);
    for (int i = 0; i < A.rowCount(); i++) {
      for (int j = 0; j < A.columnCount(); j++) {
        if (rand.nextDouble() > 0.2) continue;
        A.put(i, j, rand.nextDouble() * 23);
      }
    }
    SingularValues singular = new SingularValues(A, 10).decompose();
    Stopwatch.p();
    Out.puts(singular.value);

View Full Code Here

    managerUnderTest.addStrategy(mockedStrategy1, 0.2);
    managerUnderTest.addStrategy(mockedStrategy2, 0.8);
    
    Random mockedRandom = mock(Random.class);
    managerUnderTest.setRandom(mockedRandom);
    stub(mockedRandom.nextDouble()).toReturn(0.1);
    
    assertThat(managerUnderTest.getRandomStrategy(), is(mockedStrategy1));
    
  }

View Full Code Here

    managerUnderTest.addStrategy(mockedStrategy1, 0.2);
    managerUnderTest.addStrategy(mockedStrategy2, 0.8);
    
    Random mockedRandom = mock(Random.class);
    managerUnderTest.setRandom(mockedRandom);
    when(mockedRandom.nextDouble()).thenReturn(0.5);
    
    assertThat(managerUnderTest.getRandomStrategy(), is(mockedStrategy2));
    
  }

View Full Code Here

    managerUnderTest.addStrategy(mockedStrategy1, 0.2);
    managerUnderTest.addStrategy(mockedStrategy2, 0.8);
    
    Random mockedRandom = mock(Random.class);
    managerUnderTest.setRandom(mockedRandom);
    when(mockedRandom.nextDouble()).thenReturn(0.0);
    
    assertThat(managerUnderTest.getRandomStrategy(), is(mockedStrategy1));
    
  }

View Full Code Here

    public void fillRandoms() {
        Random random = new Random();
        for (int i = 0; i < TOTAL_RECORDS; i++) {
            for (int j = 0; j < NUM_ENTRIES_PER_RECORD; j++) {
                RANDOM_LONGS[i][j] = random.nextLong();
                RANDOM_DOUBLES[i][j] = random.nextDouble() * 1e10;
            }
            RANDOM_LONGS[i][0] = Long.MIN_VALUE;
            RANDOM_LONGS[i][1] = Long.MAX_VALUE;
            RANDOM_LONGS[i][2] = 0;
            RANDOM_DOUBLES[i][0] = 0;

View Full Code Here

          continue;
        }
        
        for (int i = 0; i < POINTS_PER_BOX; ++i) {
          
          double x = box.minX + boxSize * rand.nextDouble();
          double z = box.minZ + boxSize * rand.nextDouble();
          
          VectorXZ v = new VectorXZ(x, z);
          
          if (polygonWithHolesXZ.contains(v)) {

View Full Code Here

        }
        
        for (int i = 0; i < POINTS_PER_BOX; ++i) {
          
          double x = box.minX + boxSize * rand.nextDouble();
          double z = box.minZ + boxSize * rand.nextDouble();
          
          VectorXZ v = new VectorXZ(x, z);
          
          if (polygonWithHolesXZ.contains(v)) {

View Full Code Here

                // Write a new event. The minimum that you must set on an event is the stanza it is supposed to
                // go to (which you can skip if your modular input is not single instance, and the data of the
                // event.
                Event event = new Event();
                event.setStanza(inputName);
                event.setData("number=" + (randomGenerator.nextDouble() * (max - min) + min));


                try {
                    ew.writeEvent(event);
                } catch (MalformedDataException e) {
                    ew.synchronizedLog(EventWriter.ERROR, "MalformedDataException in writing event to input" +

View Full Code Here

        String msg;
        for(String func: mathFuncs) {
            evalFunc = (EvalFunc<Double>) Class.forName(udfPackage + func).newInstance();
            tup = TupleFactory.getInstance().newTuple(1);
            // double value between 0.0 and 1.0 
            input = generator.nextDouble();
            tup.set(0, input);
            mathMethod = Math.class.getDeclaredMethod(func.toLowerCase(), double.class);
            actual = evalFunc.exec(tup);
            expected = (Double)mathMethod.invoke(null, input);
            msg = "[Testing " + func + " on input: " + input + " ( (actual) " + actual + " == " + expected + " (expected) )]";

View Full Code Here

0 1 2 3 4 5 6 7 8 9

TOP

All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.