<s>
"	O
A	O
block	B-Algorithm
reflector	I-Algorithm
is	O
an	O
orthogonal	O
,	O
symmetric	O
matrix	B-Architecture
that	O
reverses	O
a	O
subspace	O
whose	O
dimension	O
may	O
be	O
greater	O
than	O
one.	O
"	O
</s>
<s>
It	O
is	O
built	O
out	O
of	O
many	O
elementary	B-Algorithm
reflectors	I-Algorithm
.	O
</s>
<s>
It	O
is	O
also	O
referred	O
to	O
as	O
a	O
triangular	B-Algorithm
factor	I-Algorithm
,	O
and	O
is	O
a	O
triangular	B-Algorithm
matrix	I-Algorithm
and	O
they	O
are	O
used	O
in	O
the	O
Householder	B-Algorithm
transformation	I-Algorithm
.	O
</s>
<s>
A	O
reflector	B-Algorithm
belonging	O
to	O
can	O
be	O
written	O
in	O
the	O
form	O
:	O
</s>
<s>
where	O
is	O
the	O
identity	B-Algorithm
matrix	I-Algorithm
for	O
,	O
is	O
a	O
scalar	O
and	O
belongs	O
to	O
.	O
</s>
<s>
"	O
*	O
larft	O
"	O
forms	O
the	O
triangular	O
vector	O
T	O
of	O
a	O
block	B-Algorithm
reflector	I-Algorithm
H	O
=	O
I-VTVH	O
.	O
</s>
<s>
"	O
*	O
larzb	O
"	O
applies	O
a	O
block	B-Algorithm
reflector	I-Algorithm
or	O
its	O
transpose/conjugate	O
transpose	O
as	O
returned	O
by	O
"	O
*	O
tzrzf	O
"	O
to	O
a	O
general	O
matrix	B-Architecture
.	O
</s>
<s>
"	O
*	O
larzt	O
"	O
forms	O
the	O
triangular	O
vector	O
T	O
of	O
a	O
block	B-Algorithm
reflector	I-Algorithm
H	O
=	O
I-VTVH	O
as	O
returned	O
by	O
"	O
*	O
tzrzf	O
"	O
.	O
</s>
<s>
"	O
*	O
larfb	O
"	O
applies	O
a	O
block	B-Algorithm
reflector	I-Algorithm
or	O
its	O
transpose/conjugate	O
transpose	O
to	O
a	O
general	O
rectangular	B-Architecture
matrix	I-Architecture
.	O
</s>
