SRC/zunm22.f(3)

NAME
SRC/zunm22.f

SYNOPSIS

  Functions/Subroutines
subroutine zunm22 (side, trans, m, n, n1, n2, q, ldq, c, ldc, work, lwork, info)
ZUNM22 multiplies a general matrix by a banded unitary matrix.

Function/Subroutine Documentation

  subroutine zunm22 (character side, character trans, integer m, integer n, integer n1, integer n2, complex*16, dimension( ldq, * ) q, integer ldq, complex*16, dimension( ldc, * ) c, integer ldc, complex*16, dimension( * ) work, integer lwork, integer info)

ZUNM22 multiplies a general matrix by a banded unitary matrix.

Purpose

    !>
    !>  ZUNM22 overwrites the general complex M-by-N matrix C with
    !>
    !>                  SIDE = 'L'     SIDE = 'R'
    !>  TRANS = 'N':      Q * C          C * Q
    !>  TRANS = 'C':      Q**H * C       C * Q**H
    !>
    !>  where Q is a complex unitary matrix of order NQ, with NQ = M if
    !>  SIDE = 'L' and NQ = N if SIDE = 'R'.
    !>  The unitary matrix Q processes a 2-by-2 block structure
    !>
    !>         [  Q11  Q12  ]
    !>     Q = [            ]
    !>         [  Q21  Q22  ],
    !>
    !>  where Q12 is an N1-by-N1 lower triangular matrix and Q21 is an
    !>  N2-by-N2 upper triangular matrix.
    !>

Parameters
    SIDE

    !>          SIDE is CHARACTER*1
    !>          = 'L': apply Q or Q**H from the Left;
    !>          = 'R': apply Q or Q**H from the Right.
    !>

    TRANS

    !>          TRANS is CHARACTER*1
    !>          = 'N':  apply Q (No transpose);
    !>          = 'C':  apply Q**H (Conjugate transpose).
    !>

    M

    !>          M is INTEGER
    !>          The number of rows of the matrix C. M >= 0.
    !>

    N

    !>          N is INTEGER
    !>          The number of columns of the matrix C. N >= 0.
    !>

    N1
    N2

    !>          N1 is INTEGER
    !>          N2 is INTEGER
    !>          The dimension of Q12 and Q21, respectively. N1, N2 >= 0.
    !>          The following requirement must be satisfied:
    !>          N1 + N2 = M if SIDE = 'L' and N1 + N2 = N if SIDE = 'R'.
    !>

    Q

    !>          Q is COMPLEX*16 array, dimension
    !>                              (LDQ,M) if SIDE = 'L'
    !>                              (LDQ,N) if SIDE = 'R'
    !>

    LDQ

    !>          LDQ is INTEGER
    !>          The leading dimension of the array Q.
    !>          LDQ >= max(1,M) if SIDE = 'L'; LDQ >= max(1,N) if SIDE = 'R'.
    !>

    C

    !>          C is COMPLEX*16 array, dimension (LDC,N)
    !>          On entry, the M-by-N matrix C.
    !>          On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.
    !>

    LDC

    !>          LDC is INTEGER
    !>          The leading dimension of the array C. LDC >= max(1,M).
    !>

    WORK

    !>          WORK is COMPLEX*16 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.
    !>          If SIDE = 'L', LWORK >= max(1,N);
    !>          if SIDE = 'R', LWORK >= max(1,M).
    !>          For optimum performance LWORK >= M*N.
    !>
    !>          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 had an illegal value
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 160 of file zunm22.f.

Author

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