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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dorgql.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dorgql.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dorgql.f

SYNOPSIS

Functions/Subroutines


subroutine DORGQL (m, n, k, a, lda, tau, work, lwork, info)
DORGQL

Function/Subroutine Documentation

subroutine DORGQL (integer m, integer n, integer k, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( * ) tau, double precision, dimension( * ) work, integer lwork, integer info)

DORGQL

Purpose:

!>
!> DORGQL generates an M-by-N real matrix Q with orthonormal columns,
!> which is defined as the last N columns of a product of K elementary
!> reflectors of order M
!>
!>       Q  =  H(k) . . . H(2) H(1)
!>
!> as returned by DGEQLF.
!>

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. M >= N >= 0.
!>

K

!>          K is INTEGER
!>          The number of elementary reflectors whose product defines the
!>          matrix Q. N >= K >= 0.
!>

A

!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          On entry, the (n-k+i)-th column must contain the vector which
!>          defines the elementary reflector H(i), for i = 1,2,...,k, as
!>          returned by DGEQLF in the last k columns 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 DGEQLF.
!>

WORK

!>          WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))
!>          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
!>

LWORK

!>          LWORK is INTEGER
!>          The dimension of the array WORK. LWORK >= max(1,N).
!>          For optimum performance LWORK >= N*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.
!>

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.

Definition at line 127 of file dorgql.f.

Author

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Version 3.12.0 LAPACK