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NAME
     dlaed5 - subroutine computes the I-th eigenvalue of  a  sym-
     metric  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 )



     #include <sunperf.h>

     void dlaed5(int i, double *d,  double  *dz,  double  *delta,
               double drho, double *dlam) ;

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  neces-
               sary 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  eigen-
               value.

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