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dorgr2.f(3) LAPACK dorgr2.f(3)

NAME

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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