DLARZ 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.


 H is a product of k elementary reflectors as returned by DTZRZF.

SIDE

          SIDE is CHARACTER*1


          = 'L': form  H * C


          = 'R': form  C * H

M

          M is INTEGER


          The number of rows of the matrix C.

N

          N is INTEGER


          The number of columns of the matrix C.

L

          L is INTEGER


          The number of entries of the vector V containing


          the meaningful part of the Householder vectors.


          If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.

V

          V is DOUBLE PRECISION array, dimension (1+(L-1)*abs(INCV))


          The vector v in the representation of H as returned by


          DTZRZF. V is not used if TAU = 0.

INCV

          INCV is INTEGER


          The increment between elements of v. INCV <> 0.

TAU

          TAU is DOUBLE PRECISION


          The value tau in the representation of H.

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'.

LDC

          LDC is INTEGER


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

WORK

          WORK is DOUBLE PRECISION array, dimension


                         (N) if SIDE = 'L'


                      or (M) if SIDE = 'R'

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

September 2012

A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA