SRC/dlarfg.f(3)            Library Functions Manual            SRC/dlarfg.f(3)

NAME
       SRC/dlarfg.f

SYNOPSIS
   Functions/Subroutines
       subroutine dlarfg (n, alpha, x, incx, tau)
           DLARFG generates an elementary reflector (Householder matrix).

Function/Subroutine Documentation
   subroutine dlarfg (integer n, double precision alpha, double precision,
       dimension( * ) x, integer incx, double precision tau)
       DLARFG generates an elementary reflector (Householder matrix).

       Purpose:


            DLARFG generates a real elementary reflector H of order n, such
            that

                  H * ( alpha ) = ( beta ),   H**T * H = I.
                      (   x   )   (   0  )

            where alpha and beta are scalars, and x is an (n-1)-element real
            vector. H is represented in the form

                  H = I - tau * ( 1 ) * ( 1 v**T ) ,
                                ( v )

            where tau is a real scalar and v is a real (n-1)-element
            vector.

            If the elements of x are all zero, then tau = 0 and H is taken to be
            the unit matrix.

            Otherwise  1 <= tau <= 2.

       Parameters
           N

                     N is INTEGER
                     The order of the elementary reflector.

           ALPHA

                     ALPHA is DOUBLE PRECISION
                     On entry, the value alpha.
                     On exit, it is overwritten with the value beta.

           X

                     X is DOUBLE PRECISION array, dimension
                                    (1+(N-2)*abs(INCX))
                     On entry, the vector x.
                     On exit, it is overwritten with the vector v.

           INCX

                     INCX is INTEGER
                     The increment between elements of X. INCX > 0.

           TAU

                     TAU is DOUBLE PRECISION
                     The value tau.

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 105 of file dlarfg.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/dlarfg.f(3)