SRC/dorgr2.f(3)

NAME
SRC/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 (integer m, integer n, integer k, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( * ) tau, double precision, dimension( * ) work, integer info)

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.

Definition at line 113 of file dorgr2.f.

Author

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