redhat man page for slaed5

SLAED5(l)								 )								 SLAED5(l)

NAME
       SLAED5  -  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 SLAED5( I, D, Z, DELTA, RHO, DLAM )

	   INTEGER	  I

	   REAL 	  DLAM, RHO

	   REAL 	  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) REAL array, dimension (2)
	      The original eigenvalues.  We assume D(1) < D(2).

       Z      (input) REAL array, dimension (2)
	      The components of the updating vector.

       DELTA  (output) REAL array, dimension (2)
	      The vector DELTA contains the information necessary to construct the eigenvectors.

       RHO    (input) REAL
	      The scalar in the symmetric updating formula.

       DLAM   (output) REAL
	      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 							 SLAED5(l)