cungr2.f(3)

NAME
cungr2.f -

SYNOPSIS

  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 (integerM, integerN, integerK, complex, dimension( lda, * )A, integerLDA, complex, dimension( * )TAU, complex, dimension( * )WORK, integerINFO)

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.

Date:
    September 2012

Definition at line 115 of file cungr2.f.

Author

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