cungr2.f(3)

cungr2.f3

Usage

Functions/Subroutines

subroutine cungr2 (m, n, k, a, lda, tau, work, info)
CUNGR2 generates all or part of the unitary matrix Q from an RQ factorization determined by cgerqf (unblocked algorithm).

Function/Subroutine Documentation

subroutine cungr2 (integer m, integer n, integer k, complex, dimension( lda, * ) a, integer lda, complex, dimension( * ) tau, complex, dimension( * ) work, integer info)

CUNGR2 generates all or part of the unitary matrix Q from an RQ factorization determined by cgerqf (unblocked algorithm).

Purpose:

!>
!> CUNGR2 generates an m by n complex 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 H(2)**H . . . H(k)**H
!>
!> as returned by CGERQF.
!> 

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 COMPLEX 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 CGERQF 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 COMPLEX array, dimension (K)
!>          TAU(i) must contain the scalar factor of the elementary
!>          reflector H(i), as returned by CGERQF.
!> 

WORK

!>          WORK is COMPLEX 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.

Definition at line 113 of file cungr2.f.

Releases

4 releases since Debian 7 (Wheezy); the text changed 3 times.

  1. 7
  2. 8
  3. 9
  4. Arch

Author

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