Jampack

Class Zhqrd

java.lang.Object

Jampack.Zhqrd

public class Zhqrd
extends Object

Computes a Householder QR decomposition.Specifically, given a matrix A there are is a unitary matrix U such that

    QA = R

where R is zero below its diagonal. In constructing this decomposition, Zhqrd represents Q as a product of Householder transformations with each transformation represented by a Z1. R is represented by a Zutmat. Methods are provided to apply the transformations to other matrices.
Comments: The routines to postmultiply by Q are soft coded and should ultimately be replaced.

Version:

Pre-alpha

Author:

G. W. Stewart

Field Summary

Fields

Modifier and Type	Field and Description
int	ncol The number of columns in A
int	nrow The number of rows in A
int	ntran The number of Householder transformations
Zutmat	R The R factor.
Z1[]	U An array containing the generating vectors for the Householder transformations.

Constructor Summary

Constructors

Constructor and Description
Zhqrd(Zmat A) Computes a Householder QR decomposition of a Zmat

Method Summary

Methods

Modifier and Type	Method and Description
Zmat	bq(Zmat B) Computes the product BQ.
Zmat	bqh(Zmat A, Zmat B) Computes the product BQH.
Zmat	qb(Zmat B) Computes the product QB.
Zmat	qhb(Zmat B) Computes the product QHB.

Methods inherited from class java.lang.Object

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

Field Detail

nrow

public int nrow

The number of rows in A

ncol

public int ncol

The number of columns in A

ntran

public int ntran

The number of Householder transformations

U

public Z1[] U

An array containing the generating vectors for the Householder transformations.

R

public Zutmat R

The R factor. If nrow>ncol then R is square of order ncol. Otherwise R has the same dimenstions as A.

Constructor Detail

Zhqrd

public Zhqrd(Zmat A)
      throws JampackException

Computes a Householder QR decomposition of a Zmat

Parameters:

A - A Zmat

Throws:

JampackException - Passed from below.

Method Detail

qb

public Zmat qb(Zmat B)
        throws JampackException

Computes the product QB. Throws JampackException for inconsistent dimenstions.

Parameters:

B - A Zmat

Returns:

QB

Throws:

JampackException - Thrown for inconsistent dimensions.

qhb

public Zmat qhb(Zmat B)
         throws JampackException

Computes the product Q^HB. Throws JampackException for inconsistent dimenstions.

Parameters:

B - A Zmat

Returns:

Q^HB

Throws:

JampackException - Thrown for inconsistent dimensions.

bq

public Zmat bq(Zmat B)
        throws JampackException

Computes the product BQ. Throws JampackException for inconsistent dimenstions.

Parameters:

B - A Zmat

Returns:

BQ

Throws:

JampackException - Thrown for inconsistent dimensions.

bqh

public Zmat bqh(Zmat A,
       Zmat B)
         throws JampackException

Computes the product BQ^H. Throws JampackException for inconsistent dimenstions.

Parameters:

B - A Zmat

Returns:

BQ^H

Throws:

JampackException - Thrown for inconsistent dimensions.