dlaed5(3F)

NAME
     DLAED5 - subroutine computes the I-th eigenvalue of a symmetric rank-one
     modification of a 2-by-2 diagonal matrix   diag( D ) + RHO  The diagonal
     elements in the array D are assumed to satisfy   D(i) < D(j) for i < j

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

     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.