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java.lang.Object  +Utility.RandomNumber
The RandomNumber class implements a random number
generator. It behaves as a uniform distribution in [0,1)
that gnerates doubles. It provides no support for
directly generating random integers.
It is intended to be used a parent class for other random
numbers.
Extending this class ...
When creating a subclass, be sure to use the
sample01() function instead of the nextDouble() function.
Both discrete and continuous distributions exist. The
sampleInt() function is intended to be used with discrete
distributions and the sampleDouble() function is intended
to be used with continuous distributions. To make the
class easier to use, it will not be considered an error
to call sampleDouble() for a discrete distribution. The integer
returned from sampleInt() can easily be cast to a double.
But,
in the case of calling sampleInt() for a continous
distribution, a RuntimeException will be thrown. So when
in doubt, use the sampleDouble() function.
Thus, users should pay attention to whether or not a
distribution they are using is continuous or discrete.
The RandomNumber class is treated as a continuous
distribution  Uniform [0,1).
Tests Performed
1000 samples were generated and the means and variances
were examined. Subjectively, they seemed correct.
A goodness of fit test was performed with 100 samples
and 10 intervals. It succeeded about 19/20 times.
Constructor Summary  
RandomNumber()

Method Summary  
boolean 
goodnessOfFitTest(int sampleSize,
double[] seperators,
double[] expected)
Run a chi squared Goodness of Fit Test. 
boolean 
goodnessOfFitTest(int sampleSize,
double[] seperators,
double[] expected,
int estimatedParams)
Let the user specify how many parameters had to be estimated. 
static int 
randomMixer()

static void 
resetRandomMixer(int mixer)
Reset the random_mixer to a value greater than 5, default value is 5 
protected double 
sample01()
This function returns a uniform double in the interval [0,1). 
double 
sampleDouble()
Draw a random sample. 
int 
sampleInt()
Draw a random sample. 
Methods inherited from class java.lang.Object 
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait 
Constructor Detail 
public RandomNumber()
Method Detail 
public static void resetRandomMixer(int mixer)
mixer
 Should be an integer >= 5, it denotes the
number of times mix the random number seeds.public static int randomMixer()
public double sampleDouble()
public int sampleInt()
protected double sample01()
public boolean goodnessOfFitTest(int sampleSize, double[] seperators, double[] expected)
sampleSize
 The number of samples to draw.seperators
 The upper bounds of the intervals. The
last upper bound is always +infinity, (and thus not specified).
The bounds are included in the intervals. Ex: seperators[] =
{3,4,5} would indicate four intervals: (inf,3], (3,4],
(4,5], and (5,+inf).expected
 How many observations are expected to fall in
each of the given intervals.
java.lang.RuntimeException
 Thrown if the length of the
expected array is not one bigger than the length of the
seperators array.public boolean goodnessOfFitTest(int sampleSize, double[] seperators, double[] expected, int estimatedParams)
goodnessOfFitTest(int,double,double).


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