jmathlib.toolbox.jmathlib.matrix._private.Jampack
Class Zhqrd

java.lang.Object
  extended by jmathlib.toolbox.jmathlib.matrix._private.Jampack.Zhqrd

public class Zhqrd
extends java.lang.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
 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
Zhqrd(Zmat A)
          Computes a Householder QR decomposition of a Zmat
 
Method Summary
 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 QHB. Throws JampackException for inconsistent dimenstions.

Parameters:
B - A Zmat
Returns:
QHB
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 BQH. Throws JampackException for inconsistent dimenstions.

Parameters:
B - A Zmat
Returns:
BQH
Throws:
JampackException - Thrown for inconsistent dimensions.

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