Flashnux

GNU/Linux man pages

Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :

ISBN : 978-2-7460-9712-4
EAN : 9782746097124
(Editions ENI)

GNU/Linux

CentOS 4.8

 i386

dlaed5(l)
DLAED5

DLAED5

NAME
SYNOPSIS
PURPOSE
ARGUMENTS
FURTHER DETAILS

NAME

DLAED5 - subroutine computes the I-th eigenvalue of a symmetric rank-one modification of a 2-by-2 diagonal matrix diag( D ) + RHO * Z * transpose(Z)

SYNOPSIS

SUBROUTINE DLAED5(

I, D, Z, DELTA, RHO, DLAM )

INTEGER

I

DOUBLE

PRECISION DLAM, RHO

DOUBLE

PRECISION D( 2 ), DELTA( 2 ), Z( 2 )

PURPOSE

This subroutine computes the I-th eigenvalue of a symmetric rank-one modification of a 2-by-2 diagonal matrix diag( D ) + RHO * Z * transpose(Z) . The diagonal elements in the array D are assumed to satisfy

D(i) < D(j) for i < j .

We also assume RHO > 0 and that the Euclidean norm of the vector Z is one.

ARGUMENTS

I (input) INTEGER

The index of the eigenvalue to be computed. I = 1 or I = 2.

D (input) DOUBLE PRECISION array, dimension (2)

The original eigenvalues. We assume D(1) < D(2).

Z (input) DOUBLE PRECISION array, dimension (2)

The components of the updating vector.

DELTA (output) DOUBLE PRECISION array, dimension (2)

The vector DELTA contains the information necessary to construct the eigenvectors.

RHO (input) DOUBLE PRECISION

The scalar in the symmetric updating formula.

DLAM (output) DOUBLE PRECISION

The computed lambda_I, the I-th updated eigenvalue.

FURTHER DETAILS

Based on contributions by
Ren-Cang Li, Computer Science Division, University of California
at Berkeley, USA

dlaed5(l)