org.lcsim.hmatrix
Class HMatrix

java.lang.Object
  org.lcsim.hmatrix.HMatrix

All Implemented Interfaces:

java.io.Serializable

public class HMatrix

extends java.lang.Object

implements java.io.Serializable

This class allows one to calculate how well a measurement agrees with expectations. The vector of average values and the associated covariance matrix is used to construct the HMatrix. The degree of agreement is calculated as a chi-squared of a measurement vector against the expectations. The covariance matrix is defined as:

Mij =

1 N

N å n = 1

(Ei(n) -

E

i

)(Ej(n) -

E

j

)

The H(essian)Matrix is the inverse of the covariance matrix. The chi-squared is then calculated via

zm º

N å i,j = 1

(Ei(m) -

E

i

)Hij (Ej(m) -

E

j

)

Methods to persist the HMatrix are provided in both plain ASCII format and Java serialized format.

Author:

Norman A. Graf

See Also:

Serialized Form

Constructor Summary

HMatrix(int dim, int key, double[] vec, double[][] cov)
Constructor

Method Summary

double	chisquared(double[] dat) Calculates the chi-squared for the measurement compared to the expected values and covariances represented by the HMatrix.
static HMatrix	read(java.lang.String filename) Reads the HMatrix from an ASCII file
static HMatrix	readSerialized(java.lang.String filename) Reads the HMatrix from a Serialized file
java.lang.String	toString() Output stream
void	write(java.lang.String filename, java.lang.String comment) Writes out the HMatrix to an ASCII file
void	writeSerialized(java.lang.String filename) Writes the HMatrix to a Serialized file

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

HMatrix

public HMatrix(int dim,
               int key,
               double[] vec,
               double[][] cov)

Constructor

Parameters:

key - the key for indexing this HMatrix

vec - The array of average values for the measurement space.

cov - The inverse of the covariance matrix for the averages.

Method Detail

chisquared

public double chisquared(double[] dat)

Calculates the chi-squared for the measurement compared to the expected values and covariances represented by the HMatrix.

Parameters:

dat - The array of measured values

Returns:

The value of chi-squared.

toString

public java.lang.String toString()

Output stream

Returns:

A String representation of the object.

writeSerialized

public void writeSerialized(java.lang.String filename)

Writes the HMatrix to a Serialized file

readSerialized

public static HMatrix readSerialized(java.lang.String filename)

Reads the HMatrix from a Serialized file

write

public void write(java.lang.String filename,
                  java.lang.String comment)

Writes out the HMatrix to an ASCII file

read

public static HMatrix read(java.lang.String filename)

Reads the HMatrix from an ASCII file