dorgr2.f (3) Linux Manual Page

dorgr2.f –

Synopsis

Functions/Subroutines

subroutine dorgr2 (M, N, K, A, LDA, TAU, WORK, INFO)
DORGR2 generates all or part of the orthogonal matrix Q from an RQ factorization determined by sgerqf (unblocked algorithm).

Function/Subroutine Documentation

subroutine dorgr2 (integerM, integerN, integerK, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( * )TAU, double precision, dimension( * )WORK, integerINFO)

DORGR2 generates all or part of the orthogonal matrix Q from an RQ factorization determined by sgerqf (unblocked algorithm).

Purpose:

 DORGR2 generates an m by n real matrix Q with orthonormal rows,

 which is defined as the last m rows of a product of k elementary

 reflectors of order n

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

 as returned by DGERQF.

 

Parameters:

M

 M is INTEGER

 The number of rows of the matrix Q. M >= 0.

N

 N is INTEGER

 The number of columns of the matrix Q. N >= M.

K

 K is INTEGER

 The number of elementary reflectors whose product defines the

 matrix Q. M >= K >= 0.

A

 A is DOUBLE PRECISION array, dimension (LDA,N)

 On entry, the (m-k+i)-th row must contain the vector which

 defines the elementary reflector H(i), for i = 1,2,…,k, as

 returned by DGERQF in the last k rows of its array argument

 A.

 On exit, the m by n matrix Q.

LDA

 LDA is INTEGER

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

TAU

 TAU is DOUBLE PRECISION array, dimension (K)

 TAU(i) must contain the scalar factor of the elementary

 reflector H(i), as returned by DGERQF.

WORK

 WORK is DOUBLE PRECISION array, dimension (M)

INFO

 INFO is INTEGER

 = 0: successful exit

 < 0: if INFO = -i, the i-th argument has an illegal value

 

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 115 of file dorgr2.f.

Author

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