dorgrq.f (3)  Linux Manuals
NAME
dorgrq.f 
SYNOPSIS
Functions/Subroutines
subroutine dorgrq (M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
DORGRQ
Function/Subroutine Documentation
subroutine dorgrq (integerM, integerN, integerK, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( * )TAU, double precision, dimension( * )WORK, integerLWORK, integerINFO)
DORGRQ
Purpose:

DORGRQ generates an MbyN 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.
NN is INTEGER The number of columns of the matrix Q. N >= M.
KK is INTEGER The number of elementary reflectors whose product defines the matrix Q. M >= K >= 0.
AA is DOUBLE PRECISION array, dimension (LDA,N) On entry, the (mk+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 MbyN matrix Q.
LDALDA is INTEGER The first dimension of the array A. LDA >= max(1,M).
TAUTAU is DOUBLE PRECISION array, dimension (K) TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DGERQF.
WORKWORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
LWORKLWORK is INTEGER The dimension of the array WORK. LWORK >= max(1,M). For optimum performance LWORK >= M*NB, where NB is the optimal blocksize. If LWORK = 1, then a workspace query is assumed; the routine only calculates the optimal size of the WORK array, returns this value as the first entry of the WORK array, and no error message related to LWORK is issued by XERBLA.
INFOINFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument has an illegal value
Author:

Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
 November 2011
Definition at line 129 of file dorgrq.f.
Author
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