redhat man page for dlaed5

DLAED5(l)								 )								 DLAED5(l)

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 *  trans-
       pose(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

LAPACK version 3.0						   15 June 2000 							 DLAED5(l)