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riso.approximation
Class GaussianMixApproximation  view GaussianMixApproximation download GaussianMixApproximation.java

java.lang.Object
  extended byriso.approximation.GaussianMixApproximation

public class GaussianMixApproximation
extends java.lang.Object

This class contains a public static method to create a Gaussian mixture approximation to an unconditional distribution.


Field Summary
static boolean debug
           
static double nequivalent
           
 
Constructor Summary
GaussianMixApproximation()
           
 
Method Summary
static riso.distributions.MixGaussians do_approximation(riso.distributions.Distribution target, riso.distributions.MixGaussians approximation, double[][] supports, double tolerance)
          This method creates a Gaussian mixture approximation to an unconditional distribution.
static void main(java.lang.String[] args)
          A main program to carry out the mixture approximation algorithm.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

nequivalent

public static double nequivalent

debug

public static boolean debug
Constructor Detail

GaussianMixApproximation

public GaussianMixApproximation()
Method Detail

do_approximation

public static riso.distributions.MixGaussians do_approximation(riso.distributions.Distribution target,
                                                               riso.distributions.MixGaussians approximation,
                                                               double[][] supports,
                                                               double tolerance)
                                                        throws java.lang.Exception
This method creates a Gaussian mixture approximation to an unconditional distribution. The approach is described in Sections 5.5 and 5.6 of my dissertation. Briefly, the usual expectation-maximization algorithm for fitting a mixture to data is generalized to fitting a mixture to a continuous density. Discrete summations are replaced by integrations -- integrands are constructed as instances of helper classes. An effort is made to simplify the resulting mixture by throwing out components which have little mass or which are redundant with another component.


main

public static void main(java.lang.String[] args)
A main program to carry out the mixture approximation algorithm. Usage:
   java riso.approximation.GaussianMixApproximation target approx0 x0 x1 N
 
where
  1. target File containing description of the target distribution.
  2. approx0 File containing description of the initial approximation.
  3. x0, x1 Endpoints of the interval over which to construct the approximation.
  4. N Equivalent sample size. This is essentially a regularization parameter.