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man pages->IRIX man pages -> complib/dorg2r (3)
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### Contents

```
DORG2R(3F)							    DORG2R(3F)

```

### NAME[Toc][Back]

```     DORG2R - generate an m by n real matrix Q with orthonormal	columns,
```

### SYNOPSIS[Toc][Back]

```     SUBROUTINE	DORG2R(	M, N, K, A, LDA, TAU, WORK, INFO )

INTEGER	INFO, K, LDA, M, N

DOUBLE		PRECISION A( LDA, * ), TAU( * ), WORK( * )
```

### PURPOSE[Toc][Back]

```     DORG2R generates an m by n	real matrix Q with orthonormal columns,	which
is	defined	as the first n columns of a product of k elementary reflectors
of	order m

Q  =	 H(1) H(2) . . . H(k)

as	returned by DGEQRF.

```

### ARGUMENTS[Toc][Back]

```     M	     (input) INTEGER
The number	of rows	of the matrix Q. M >= 0.

N	     (input) INTEGER
The number	of columns of the matrix Q. M >= N >= 0.

K	     (input) INTEGER
The number	of elementary reflectors whose product defines the
matrix Q. N >= K >= 0.

A	     (input/output) DOUBLE PRECISION array, dimension (LDA,N)
On	entry, the i-th	column must contain the	vector which defines
the elementary reflector H(i), for	i = 1,2,...,k, as returned by
DGEQRF in the first k columns of its array	argument A.  On	exit,
the m-by-n	matrix Q.

LDA     (input) INTEGER
The first dimension of the	array A. LDA >=	max(1,M).

TAU     (input) DOUBLE PRECISION array, dimension (K)
TAU(i) must contain the scalar factor of the elementary reflector
H(i), as returned by DGEQRF.

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

INFO    (output) INTEGER
= 0: successful exit
< 0: if INFO = -i,	the i-th argument has an illegal value
DORG2R(3F)							    DORG2R(3F)

```

### NAME[Toc][Back]

```     DORG2R - generate an m by n real matrix Q with orthonormal	columns,
```

### SYNOPSIS[Toc][Back]

```     SUBROUTINE	DORG2R(	M, N, K, A, LDA, TAU, WORK, INFO )

INTEGER	INFO, K, LDA, M, N

DOUBLE		PRECISION A( LDA, * ), TAU( * ), WORK( * )
```

### PURPOSE[Toc][Back]

```     DORG2R generates an m by n	real matrix Q with orthonormal columns,	which
is	defined	as the first n columns of a product of k elementary reflectors
of	order m

Q  =	 H(1) H(2) . . . H(k)

as	returned by DGEQRF.

```

### ARGUMENTS[Toc][Back]

```     M	     (input) INTEGER
The number	of rows	of the matrix Q. M >= 0.

N	     (input) INTEGER
The number	of columns of the matrix Q. M >= N >= 0.

K	     (input) INTEGER
The number	of elementary reflectors whose product defines the
matrix Q. N >= K >= 0.

A	     (input/output) DOUBLE PRECISION array, dimension (LDA,N)
On	entry, the i-th	column must contain the	vector which defines
the elementary reflector H(i), for	i = 1,2,...,k, as returned by
DGEQRF in the first k columns of its array	argument A.  On	exit,
the m-by-n	matrix Q.

LDA     (input) INTEGER
The first dimension of the	array A. LDA >=	max(1,M).

TAU     (input) DOUBLE PRECISION array, dimension (K)
TAU(i) must contain the scalar factor of the elementary reflector
H(i), as returned by DGEQRF.

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

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

PPPPaaaaggggeeee 1111```
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