HP MLIB User's Guide Vol. 1 7th Ed.

Chapter 2 Basic Vector Operations 177
Generate Householder transform F_SGEN_HOUSE/F_DGEN_HOUSE/F_CGEN_HOUSE/F_ZGEN_HOUSE
X REAL or COMPLEX array, minimum length
(N - 1) x |incx| + 1).
INCX Increment for the array x. A vector x having component
x
i
, i = 1,..., n, is stored in an array X() with increment
argument incx. If incx > 0 then x
i
is stored in
X (1 + (i - 1) x incx). If incx < 0 then x
i
is stored in
X (1 + (N - i) x |incx|). incx = 0 is an illegal value.
Output TAU REAL or COMPLEX scalar. If n = 0, F_xGEN_HOUSE
returns immediately with TAU set to zero.