LAPACK  3.5.0
LAPACK: Linear Algebra PACKage
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slarf.f File Reference

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Functions/Subroutines

subroutine slarf (SIDE, M, N, V, INCV, TAU, C, LDC, WORK)
 SLARF applies an elementary reflector to a general rectangular matrix. More...
 

Function/Subroutine Documentation

subroutine slarf ( character  SIDE,
integer  M,
integer  N,
real, dimension( * )  V,
integer  INCV,
real  TAU,
real, dimension( ldc, * )  C,
integer  LDC,
real, dimension( * )  WORK 
)

SLARF applies an elementary reflector to a general rectangular matrix.

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

Purpose:
 SLARF 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 REAL 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 REAL
          The value tau in the representation of H.
[in,out]C
          C is REAL 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 REAL 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.
Date
September 2012

Definition at line 125 of file slarf.f.

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