DOPGTR(l)		LAPACK routine (version	2.0)		    DOPGTR(l)



NAME
  DOPGTR - generate a real orthogonal matrix Q which is	defined	as the pro-
  duct of n-1 elementary reflectors H(i) of order n, as	returned by DSPTRD
  using	packed storage

SYNOPSIS

  SUBROUTINE DOPGTR( UPLO, N, AP, TAU, Q, LDQ, WORK, INFO )

      CHARACTER	     UPLO

      INTEGER	     INFO, LDQ,	N

      DOUBLE	     PRECISION AP( * ),	Q( LDQ,	* ), TAU( * ), WORK( * )

PURPOSE
  DOPGTR generates a real orthogonal matrix Q which is defined as the product
  of n-1 elementary reflectors H(i) of order n,	as returned by DSPTRD using
  packed storage:

  if UPLO = 'U', Q = H(n-1) . .	. H(2) H(1),

  if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).


ARGUMENTS

  UPLO	  (input) CHARACTER*1
	  = 'U': Upper triangular packed storage used in previous call to
	  DSPTRD; = 'L': Lower triangular packed storage used in previous
	  call to DSPTRD.

  N	  (input) INTEGER
	  The order of the matrix Q. N >= 0.

  AP	  (input) DOUBLE PRECISION array, dimension (N*(N+1)/2)
	  The vectors which define the elementary reflectors, as returned by
	  DSPTRD.

  TAU	  (input) DOUBLE PRECISION array, dimension (N-1)
	  TAU(i) must contain the scalar factor	of the elementary reflector
	  H(i),	as returned by DSPTRD.

  Q	  (output) DOUBLE PRECISION array, dimension (LDQ,N)
	  The N-by-N orthogonal	matrix Q.

  LDQ	  (input) INTEGER
	  The leading dimension	of the array Q.	LDQ >= max(1,N).

  WORK	  (workspace) DOUBLE PRECISION array, dimension	(N-1)

  INFO	  (output) INTEGER
	  = 0:	successful exit
	  < 0:	if INFO	= -i, the i-th argument	had an illegal value