ungl2(3)

NAME
ungl2 - {un,or}gl2: generate explicit Q, level 2, step in unglq

SYNOPSIS

  Functions
subroutine cungl2 (m, n, k, a, lda, tau, work, info)
CUNGL2 generates all or part of the unitary matrix Q from an LQ factorization determined by cgelqf (unblocked algorithm).
subroutine dorgl2 (m, n, k, a, lda, tau, work, info)
DORGL2
subroutine sorgl2 (m, n, k, a, lda, tau, work, info)
SORGL2
subroutine zungl2 (m, n, k, a, lda, tau, work, info)
ZUNGL2 generates all or part of the unitary matrix Q from an LQ factorization determined by cgelqf (unblocked algorithm).

Detailed Description

Function Documentation

  subroutine cungl2 (integer m, integer n, integer k, complex, dimension( lda, * ) a, integer lda, complex, dimension( * ) tau, complex, dimension( * ) work, integer info)

CUNGL2 generates all or part of the unitary matrix Q from an LQ factorization determined by cgelqf (unblocked algorithm).

Purpose:

     CUNGL2 generates an m-by-n complex matrix Q with orthonormal rows,
     which is defined as the first m rows of a product of k elementary
     reflectors of order n
           Q  =  H(k)**H . . . H(2)**H H(1)**H
     as returned by CGELQF.

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 i-th row must contain the vector which defines
              the elementary reflector H(i), for i = 1,2,...,k, as returned
              by CGELQF in the first 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 CGELQF.

    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 112 of file cungl2.f.

  subroutine dorgl2 (integer m, integer n, integer k, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( * ) tau, double precision, dimension( * ) work, integer info)

DORGL2

Purpose:

     DORGL2 generates an m by n real matrix Q with orthonormal rows,
     which is defined as the first m rows of a product of k elementary
     reflectors of order n
           Q  =  H(k) . . . H(2) H(1)
     as returned by DGELQF.

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 i-th row must contain the vector which defines
              the elementary reflector H(i), for i = 1,2,...,k, as returned
              by DGELQF in the first 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 DGELQF.

    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 112 of file dorgl2.f.

  subroutine sorgl2 (integer m, integer n, integer k, real, dimension( lda, * ) a, integer lda, real, dimension( * ) tau, real, dimension( * ) work, integer info)

SORGL2

Purpose:

     SORGL2 generates an m by n real matrix Q with orthonormal rows,
     which is defined as the first m rows of a product of k elementary
     reflectors of order n
           Q  =  H(k) . . . H(2) H(1)
     as returned by SGELQF.

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 REAL array, dimension (LDA,N)
              On entry, the i-th row must contain the vector which defines
              the elementary reflector H(i), for i = 1,2,...,k, as returned
              by SGELQF in the first 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 REAL array, dimension (K)
              TAU(i) must contain the scalar factor of the elementary
              reflector H(i), as returned by SGELQF.

    WORK

              WORK is REAL 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 112 of file sorgl2.f.

  subroutine zungl2 (integer m, integer n, integer k, complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension( * ) tau, complex*16, dimension( * ) work, integer info)

ZUNGL2 generates all or part of the unitary matrix Q from an LQ factorization determined by cgelqf (unblocked algorithm).

Purpose:

     ZUNGL2 generates an m-by-n complex matrix Q with orthonormal rows,
     which is defined as the first m rows of a product of k elementary
     reflectors of order n
           Q  =  H(k)**H . . . H(2)**H H(1)**H
     as returned by ZGELQF.

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*16 array, dimension (LDA,N)
              On entry, the i-th row must contain the vector which defines
              the elementary reflector H(i), for i = 1,2,...,k, as returned
              by ZGELQF in the first 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*16 array, dimension (K)
              TAU(i) must contain the scalar factor of the elementary
              reflector H(i), as returned by ZGELQF.

    WORK

              WORK is COMPLEX*16 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 112 of file zungl2.f.

Author

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