Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

p?larz

Applies an elementary reflector as returned by
p?tzrzf
to a general matrix.

Syntax

call pslarz
(
side
,
m
,
n
,
l
,
v
,
iv
,
jv
,
descv
,
incv
,
tau
,
c
,
ic
,
jc
,
descc
,
work
)
call pdlarz
(
side
,
m
,
n
,
l
,
v
,
iv
,
jv
,
descv
,
incv
,
tau
,
c
,
ic
,
jc
,
descc
,
work
)
call pclarz
(
side
,
m
,
n
,
l
,
v
,
iv
,
jv
,
descv
,
incv
,
tau
,
c
,
ic
,
jc
,
descc
,
work
)
call pzlarz
(
side
,
m
,
n
,
l
,
v
,
iv
,
jv
,
descv
,
incv
,
tau
,
c
,
ic
,
jc
,
descc
,
work
)
Description
The
p?larz
routine
applies a real/complex elementary reflector
Q
(or
Q
T
) to a real/complex
m
-by-
n
distributed matrix
sub(
C
) =
C
(
ic
:
ic
+
m
-1
,
jc
:
jc
+
n
-1)
, from either the left or the right.
Q
is represented in the form
Q
= I-
tau
*
v
*
v'
,
where
tau
is a real/complex scalar and
v
is a real/complex vector.
If
tau
= 0
, then
Q
is taken to be the unit matrix.
Q
is a product of
k
elementary reflectors as returned by
p?tzrzf
.
Input Parameters
side
(global)
CHARACTER
.
if
side
=
'L'
: form
Q
*sub(
C
),
if
side
=
'R'
: form sub
(
C
)*
Q
,
Q
=
Q
T
(for real flavors).
m
(global)
INTEGER
.
The number of rows in the distributed matrix sub(
C
).
(
m
0)
.
n
(global)
INTEGER
.
The number of columns in the distributed matrix sub(
C
).
(
n
0)
.
l
(global)
INTEGER
.
The columns of the distributed matrix sub(
A
) containing the meaningful part of the Householder reflectors. If
side
=
'L'
,
m
l
0,
if
side
=
'R'
,
n
l
0
.
v
(local).
REAL
for
pslarz