Class edu.cornell.lassp.houle.RngPack.RandomElement
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Class edu.cornell.lassp.houle.RngPack.RandomElement
java.lang.Object

+edu.cornell.lassp.houle.RngPack.RandomElement
 public class RandomElement
 extends Object
RandomElement is an abstract class that encapsulates random number
generators. To base a class on it, you must define the method
raw()
as described below. It is also likely that you
will want to define a constructor or another mechanism for seeding the
the generator. The other classes defined in RandomElement
add value to the numbers generated by raw()
Source code is available.
 Version:
 1.0
 Author:
 Paul Houle (Email: houle@msc.cornell.edu)
 See Also:
 RandomJava, RandomShuffle

RandomElement()


choose(int)


choose(int, int)


gaussian()

gaussian() uses the BoxMuller algorithm to transform raw()'s into
gaussian deviates.

gaussian(double)


powlaw(double, double)

generate a powerlaw distribution with exponent
alpha
and lower cutoff
cut

raw()
 The abstract method that must be defined to make a working RandomElement.

raw(double[], int)
 Fill part or all of an array with doubles.

raw(double[])
 Fill an entire array with doubles.

uniform(double, double)

RandomElement
public RandomElement()
raw
public abstract double raw()
 The abstract method that must be defined to make a working RandomElement.
See the class
RandomJava
for an example of how to do this.
 Returns:
 a random double in the range [0,1]
 See Also:
 RandomJava
raw
public void raw(double d[],
int n)
 Fill part or all of an array with doubles. The method defined here uses multiple calls to
raw()
to fill the array. You can eliminate the overhead of
multiple method calls by subclassing this with a version of the generator
that fills the array. On our system this improves the efficiency of
Ranecu
by 20% when filling large arrays.
 Parameters:
 d  array to be filled with doubles
 n  number of doubles to generate
raw
public void raw(double d[])
 Fill an entire array with doubles. This method calls
raw(double d[],int n)
with d=d.length
. Since this adds little overhead for d.length
large, it is only necessary to override raw(double d[],int n)
 Parameters:
 d  array to be filled with doubles.
choose
public int choose(int hi)
 Parameters:
 hi  upper limit of range
 Returns:
 a random integer in the range 1,2,... ,hi
choose
public int choose(int lo,
int hi)
 Parameters:
 lo  lower limit of range
 hi  upper limit of range
 Returns:
 a random integer in the range lo, lo+1, ... ,hi
uniform
public double uniform(double lo,
double hi)
 Parameters:
 lo  lower limit of range
 hi  upper limit of range
 Returns:
 a uniform random real in the range [lo,hi]
gaussian
public double gaussian()
 gaussian() uses the BoxMuller algorithm to transform raw()'s into
gaussian deviates.
 Returns:
 a random real with a gaussian distribution, standard deviation
gaussian
public double gaussian(double sd)
 Parameters:
 sd  standard deviation
 Returns:
 a gaussian distributed random real with standard deviation sd
powlaw
public double powlaw(double alpha,
double cut)
 generate a powerlaw distribution with exponent
alpha
and lower cutoff
cut
 Parameters:
 alpha  the exponent
 cut  the lower cutoff
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