Jampack

Class House

java.lang.Object

Jampack.House

public class House
extends Object

House provides static methods to generate and apply Householder transformations.

Version:

Pre-alpha

Author:

G. W. Stewart

Constructor Summary

Constructors

Constructor and Description
House()

Method Summary

Methods

Modifier and Type	Method and Description
static Zmat	au(Zmat A, Z1 u, int r1, int r2, int c1, int c2) Postmultiplies the Householder transformation contained in a Z1 into a Zmat A[r1:r2,c1:c2] and overwrites Zmat A[r1:r2,c1:c2] with the results.
static Zmat	au(Zmat A, Z1 u, int r1, int r2, int c1, int c2, Z1 v) Postmultiplies the Householder transformation contained in a Z1 into a Zmat A[r1:r2,c1:c2] and overwrites Zmat A[r1:r2,c1:c2] with the results.
static Z1	genc(Zmat A, int r1, int r2, int c) Generates a Householder transformation from within the part of column c of a Zmat (altered) extending from rows r1 to r2.
static Z1	genr(Zmat A, int r, int c1, int c2) Generates a Householder transformation from within the part of row r of a Zmat (altered) extending from columns c1 to c2.
static Zmat	ua(Z1 u, Zmat A, int r1, int r2, int c1, int c2) Premultiplies the Householder transformation contained in a Z1 into a Zmat A[r1:r2,c1:c2] and overwrites Zmat A[r1:r2,c1:c2] with the results.
static Zmat	ua(Z1 u, Zmat A, int r1, int r2, int c1, int c2, Z1 v) Premultiplies the Householder transformation contained in a Z1 into a Zmat A[r1:r2,c1:c2] and overwrites Zmat A[r1:r2,c1:c2] with the results.

Methods inherited from class java.lang.Object

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

Constructor Detail

House

public House()

Method Detail

genc

public static Z1 genc(Zmat A,
      int r1,
      int r2,
      int c)
               throws JampackException

Generates a Householder transformation from within the part of column c of a Zmat (altered) extending from rows r1 to r2. The method overwrites the column with the result of applying the transformation.

Parameters:

A - The matrix from which the transformation is to be generated (altered)

r1 - The index of the row in which the generating column begins

r2 - The index of the row in which the generating column ends

c - The index of the generating column

Returns:

A Z1 of length r2-r1+1 containing the Householder vector

Throws:

JampackException - Passed from below.

genr

public static Z1 genr(Zmat A,
      int r,
      int c1,
      int c2)
               throws JampackException

Generates a Householder transformation from within the part of row r of a Zmat (altered) extending from columns c1 to c2. The method overwrites the row with the result of applying the transformation.

Parameters:

A - The matrix from which the transformation is to be generated (altered)

r - The index of the generating row

c1 - The index of the column in which the generating row begins

c2 - The index of the column in which the generating row ends

Returns:

A Z1 of length r2-r1+1 containing the Householder vector

Throws:

JampackException - Passed from below.

ua

public static Zmat ua(Z1 u,
      Zmat A,
      int r1,
      int r2,
      int c1,
      int c2,
      Z1 v)
               throws JampackException

Premultiplies the Householder transformation contained in a Z1 into a Zmat A[r1:r2,c1:c2] and overwrites Zmat A[r1:r2,c1:c2] with the results. If r1 > r2 or c1 > c2 the method does nothing.

Parameters:

u - The Householder vector

A - The Zmat to which the transformation is to be applied (altered)

r1 - The index of the first row to which the transformation is to be applied

r2 - The index of the last row to which the transformation is to be applied

c1 - The index of the first column to which the transformation is index of the to be applied

c2 - The index of the last column to which the transformation is to be applied

v - A work array of length at least c2-c1+1

Returns:

The transformed Zmat A

Throws:

JampackException - Thrown if either u or v is too short.

ua

public static Zmat ua(Z1 u,
      Zmat A,
      int r1,
      int r2,
      int c1,
      int c2)
               throws JampackException

Premultiplies the Householder transformation contained in a Z1 into a Zmat A[r1:r2,c1:c2] and overwrites Zmat A[r1:r2,c1:c2] with the results. If r1 > r2 or c1 > c2 the method does nothing.

Parameters:

u - The Householder vector

A - The Zmat to which the transformation is to be applied (altered)

r1 - The index of the first row to which the transformation is to be applied

r2 - The index of the last row to which the transformation is to be applied

c1 - The index of the first column to which the transformation is index of the to be applied

c2 - The index of the last column to which the transformation is to be applied

Returns:

The transformed Zmat A

Throws:

JampackException - Passed from below.

au

public static Zmat au(Zmat A,
      Z1 u,
      int r1,
      int r2,
      int c1,
      int c2,
      Z1 v)
               throws JampackException

Postmultiplies the Householder transformation contained in a Z1 into a Zmat A[r1:r2,c1:c2] and overwrites Zmat A[r1:r2,c1:c2] with the results. If r1 > r2 or c1 > c2 the method does nothing.

Parameters:

u - The Householder vector

A - The Zmat to which the transformation is to be applied (altered)

r1 - The index of the first row to which the transformation is to be applied

r2 - The index of the last row to which the transformation is to be applied

c1 - The index of the first column to which the transformation is index of the to be applied

c2 - The index of the last column to which the transformation is to be applied

v - A work array of length at least c2-c1+1

Returns:

The transformed Zmat A

Throws:

JampackException - Thrown if either u or v is too short.

au

public static Zmat au(Zmat A,
      Z1 u,
      int r1,
      int r2,
      int c1,
      int c2)
               throws JampackException

Postmultiplies the Householder transformation contained in a Z1 into a Zmat A[r1:r2,c1:c2] and overwrites Zmat A[r1:r2,c1:c2] with the results. If r1 > r2 or c1 > c2 the method does nothing.

Parameters:

u - The Householder vector

A - The Zmat to which the transformation is to be applied (altered)

r1 - The index of the first row to which the transformation is to be applied

r2 - The index of the last row to which the transformation is to be applied

c1 - The index of the first column to which the transformation is index of the to be applied

c2 - The index of the last column to which the transformation is to be applied

Returns:

The transformed Zmat A

Throws:

JampackException - Passed from below.