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## dlarf1l()

subroutine dlarf1l | ( | character | side,
|  | integer | m,
|  | integer | n,
|  | double precision, dimension( * ) | v,
|  | integer | incv,
|  | double precision | tau,
|  | double precision, dimension( ldc, * ) | c,
|  | integer | ldc,
|  | double precision, dimension( * ) | work )

DLARF1L applies an elementary reflector to a general rectangular

Download DLARF1L + dependencies [TGZ] [ZIP] [TXT]

Purpose:

      !>
      !> DLARF1L applies a real elementary reflector H to a real m by n matrix
      !> C, from either the left or the right. H is represented in the form
      !>
      !>       H = I - tau * v * v**T
      !>
      !> where tau is a real scalar and v is a real vector.
      !>
      !> If tau = 0, then H is taken to be the unit matrix.
      !>

Parameters

  [in]

  SIDE

      !>          SIDE is CHARACTER*1
      !>          = 'L': form  H * C
      !>          = 'R': form  C * H
      !>

  [in]

  M

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

  [in]

  N

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

  [in]

  V

      !>          V is DOUBLE PRECISION array, dimension
      !>                     (1 + (M-1)*abs(INCV)) if SIDE = 'L'
      !>                  or (1 + (N-1)*abs(INCV)) if SIDE = 'R'
      !>          The vector v in the representation of H. V is not used if
      !>          TAU = 0.
      !>

  [in]

  INCV

      !>          INCV is INTEGER
      !>          The increment between elements of v. INCV <> 0.
      !>

  [in]

  TAU

      !>          TAU is DOUBLE PRECISION
      !>          The value tau in the representation of H.
      !>

  [in,out]

  C

      !>          C is DOUBLE PRECISION array, dimension (LDC,N)
      !>          On entry, the m by n matrix C.
      !>          On exit, C is overwritten by the matrix H * C if SIDE = 'L',
      !>          or C * H if SIDE = 'R'.
      !>

  [in]

  LDC

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

  [out]

  WORK

      !>          WORK is DOUBLE PRECISION array, dimension
      !>                         (N) if SIDE = 'L'
      !>                      or (M) if SIDE = 'R'
      !>

Author
  Univ. of Tennessee
  Univ. of California Berkeley
  Univ. of Colorado Denver
  NAG Ltd.