DOPGTR(3F)							    DOPGTR(3F)

NAME    [Toc]    [Back]

     DOPGTR - generate 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

SYNOPSIS    [Toc]    [Back]

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

	 CHARACTER	UPLO

	 INTEGER	INFO, LDQ, N

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

PURPOSE    [Toc]    [Back]

     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    [Toc]    [Back]

     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
DOPGTR(3F)							    DOPGTR(3F)

NAME    [Toc]    [Back]

     DOPGTR - generate 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

SYNOPSIS    [Toc]    [Back]

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

	 CHARACTER	UPLO

	 INTEGER	INFO, LDQ, N

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

PURPOSE    [Toc]    [Back]

     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    [Toc]    [Back]

     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


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