SLATZM (3lapack)

applie a Householder matrix generated by STZRQF to a matrix

SYNOPSIS

  SUBROUTINE SLATZM( SIDE, M, N, V, INCV, TAU, C1, C2, LDC, WORK )

      CHARACTER      SIDE

      INTEGER        INCV, LDC, M, N

      REAL           TAU

      REAL           C1( LDC, * ), C2( LDC, * ), V( * ), WORK( * )

PURPOSE

  SLATZM applies a Householder matrix generated by STZRQF to a matrix.

  Let P = I - tau*u*u',   u = ( 1 ),
                              ( v )
  where v is an (m-1) vector if SIDE = 'L', or a (n-1) vector if SIDE = 'R'.

  If SIDE equals 'L', let
         C = [ C1 ] 1
             [ C2 ] m-1
               n
  Then C is overwritten by P*C.

  If SIDE equals 'R', let
         C = [ C1, C2 ] m
                1  n-1
  Then C is overwritten by C*P.

ARGUMENTS

  SIDE    (input) CHARACTER*1
          = 'L': form P * C
          = 'R': form C * P

  M       (input) INTEGER
          The number of rows of the matrix C.

  N       (input) INTEGER
          The number of columns of the matrix C.

  V       (input) REAL array, dimension
          (1 + (M-1)*abs(INCV)) if SIDE = 'L' (1 + (N-1)*abs(INCV)) if SIDE =
          'R' The vector v in the representation of P. V is not used if TAU =
          0.

  INCV    (input) INTEGER
          The increment between elements of v. INCV <> 0

  TAU     (input) REAL
          The value tau in the representation of P.

  C1      (input/output) REAL array, dimension
          (LDC,N) if SIDE = 'L' (M,1)   if SIDE = 'R' On entry, the n-vector
          C1 if SIDE = 'L', or the m-vector C1 if SIDE = 'R'.

          On exit, the first row of P*C if SIDE = 'L', or the first column of
          C*P if SIDE = 'R'.

  C2      (input/output) REAL array, dimension
          (LDC, N)   if SIDE = 'L' (LDC, N-1) if SIDE = 'R' On entry, the (m
          - 1) x n matrix C2 if SIDE = 'L', or the m x (n - 1) matrix C2 if
          SIDE = 'R'.

          On exit, rows 2:m of P*C if SIDE = 'L', or columns 2:m of C*P if
          SIDE = 'R'.

  LDC     (input) INTEGER
          The leading dimension of the arrays C1 and C2. LDC >= (1,M).

  WORK    (workspace) REAL array, dimension
          (N) if SIDE = 'L' (M) if SIDE = 'R'