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

                            rand = new Random();
                        }


                        try
                        {
                            Thread.sleep(500l + (long)(500l * rand.nextDouble()));
                        }
                        catch (InterruptedException e1)
                        {


                        }

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    rnm2 = svd_ddot(n, wptr[0], 1, wptr[0], 1);
    Random random = new Random(918273L + step); // irand = 918273 + step;
    r = wptr[0];
    for (id = 0; id < 3; id++) {
      if (id > 0 || step > 0 || rnm2 == 0) 
        for (i = 0; i < n; i++) r[i] = random.nextDouble(); // svd_random2(&irand);
      svd_dcopy(n, wptr[0], 1, wptr[3], 1);


      /* apply operator to put r in range (essential if m singular) */
      svd_opb(A, wptr[3], wptr[0], OPBTemp);
      svd_dcopy(n, wptr[0], 1, wptr[3], 1);

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      while (idx < orig.length) {
        float val = rand.nextFloat();
        orig[idx] = val;
        fromEmpty.set(idx, val);
        idx += 1;
        while (rand.nextDouble() > density) {
          idx++;
        }
      }
      float[] copy = new float[orig.length];
      System.arraycopy(orig, 0, copy, 0, orig.length);

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      AffineTransform currentAf = properties.getAffineTransform();
      AffineTransform af = new AffineTransform();
      af.scale(properties.getAffineTransform().getScaleX(), currentAf.getScaleY());


      if (currentAf.getTranslateX() != 0 || currentAf.getTranslateY() != 0) {
          af.translate(r.nextDouble() * currentAf.getTranslateX(), r.nextDouble() * currentAf.getTranslateY());
      }


      if (currentAf.getShearX() != 0 || currentAf.getShearY() != 0) {
          af.shear(r.nextDouble() * currentAf.getShearX(), r.nextDouble() * currentAf.getShearY());
      }

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      AffineTransform currentAf = properties.getAffineTransform();
      AffineTransform af = new AffineTransform();
      af.scale(properties.getAffineTransform().getScaleX(), currentAf.getScaleY());


      if (currentAf.getTranslateX() != 0 || currentAf.getTranslateY() != 0) {
          af.translate(r.nextDouble() * currentAf.getTranslateX(), r.nextDouble() * currentAf.getTranslateY());
      }


      if (currentAf.getShearX() != 0 || currentAf.getShearY() != 0) {
          af.shear(r.nextDouble() * currentAf.getShearX(), r.nextDouble() * currentAf.getShearY());
      }

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      if (currentAf.getTranslateX() != 0 || currentAf.getTranslateY() != 0) {
          af.translate(r.nextDouble() * currentAf.getTranslateX(), r.nextDouble() * currentAf.getTranslateY());
      }


      if (currentAf.getShearX() != 0 || currentAf.getShearY() != 0) {
          af.shear(r.nextDouble() * currentAf.getShearX(), r.nextDouble() * currentAf.getShearY());
      }


      if (properties.getMaxRotationAngle() != 0) {
          af.rotate(r.nextDouble() / 360);
      }

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      if (currentAf.getTranslateX() != 0 || currentAf.getTranslateY() != 0) {
          af.translate(r.nextDouble() * currentAf.getTranslateX(), r.nextDouble() * currentAf.getTranslateY());
      }


      if (currentAf.getShearX() != 0 || currentAf.getShearY() != 0) {
          af.shear(r.nextDouble() * currentAf.getShearX(), r.nextDouble() * currentAf.getShearY());
      }


      if (properties.getMaxRotationAngle() != 0) {
          af.rotate(r.nextDouble() / 360);
      }

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      if (currentAf.getShearX() != 0 || currentAf.getShearY() != 0) {
          af.shear(r.nextDouble() * currentAf.getShearX(), r.nextDouble() * currentAf.getShearY());
      }


      if (properties.getMaxRotationAngle() != 0) {
          af.rotate(r.nextDouble() / 360);
      }


      AffineTransformOp op = new AffineTransformOp(af, AffineTransformOp.TYPE_BILINEAR);
      BufferedImage dest = new BufferedImage((int) (i.getWidth() / af.getScaleX()), (int) (i.getHeight() / af.getScaleY()), BufferedImage.TYPE_3BYTE_BGR);
      op.filter(i, dest);

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      int count = 0;
      while (idx < orig.length) {
        orig[idx] = rand.nextFloat();
        count++;
        idx += 1;
        while (rand.nextDouble() > density) {
          idx++;
        }
      }
      assertTrue("count was bad: " + count, count > 100 && count < orig.length / 2);
      System.out.println("float array with " + count + " out of " + orig.length

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        rnm2 = svd_ddot(n, wptr[0], 1, wptr[0], 1);
        Random random = new Random(918273L + step); // irand = 918273 + step;
        r = wptr[0];
        for (id = 0; id < 3; id++) {
            if (id > 0 || step > 0 || rnm2 == 0) 
                for (i = 0; i < n; i++) r[i] = random.nextDouble(); // svd_random2(&irand);
            svd_dcopy(n, wptr[0], 1, wptr[3], 1);


            /* apply operator to put r in range (essential if m singular) */
            svd_opb(A, wptr[3], wptr[0], OPBTemp);
            svd_dcopy(n, wptr[0], 1, wptr[3], 1);

View Full Code Here

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