DLAED5(3F)							    DLAED5(3F)

NAME    [Toc]    [Back]

     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    [Toc]    [Back]

     SUBROUTINE	DLAED5(	I, D, Z, DELTA,	RHO, DLAM )

	 INTEGER	I

	 DOUBLE		PRECISION DLAM,	RHO

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

PURPOSE    [Toc]    [Back]

     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    [Toc]    [Back]

     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.
DLAED5(3F)							    DLAED5(3F)

NAME    [Toc]    [Back]

     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    [Toc]    [Back]

     SUBROUTINE	DLAED5(	I, D, Z, DELTA,	RHO, DLAM )

	 INTEGER	I

	 DOUBLE		PRECISION DLAM,	RHO

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

PURPOSE    [Toc]    [Back]

     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    [Toc]    [Back]

     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.


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