Developer Reference

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

p?tzrzf

Reduces the upper trapezoidal matrix
A
to upper triangular form.

Syntax

call pstzrzf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
call pdtzrzf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
call pctzrzf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
call pztzrzf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
Include Files
Description
The
p?tzrzf
routine
reduces the
m
-by-
n
(
m
n
) real/complex upper trapezoidal matrix sub(
A
)=
A
(
ia
:
ia
+
m
-1,
ja
:
ja
+
n
-1) to upper triangular form by means of orthogonal/unitary transformations. The upper trapezoidal matrix
A
is factored as
A
= (
R
0)*
Z
,
where
Z
is an
n
-by-
n
orthogonal/unitary matrix and
R
is an
m
-by-
m
upper triangular matrix.
Input Parameters
m
(global)
INTEGER
.
The number of rows in the matrix sub(
A
);
(
m
0)
.
n
(global)
INTEGER
.
The number of columns in the matrix sub(
A
)
(
n
0)
.
a
(local)
REAL
for
pstzrzf
DOUBLE PRECISION
for
pdtzrzf
.
COMPLEX
for
pctzrzf
.
DOUBLE COMPLEX
for
pztzrzf
.
Pointer into the local memory to an array of size
(
lld_a
,
LOCc
(
ja
+
n
-1))
. Contains the local pieces of the
m
-by-
n
distributed matrix sub (
A
) to be factored.
ia
,
ja
(global)
INTEGER
.
The row and column indices in the global matrix
A
indicating the first row and the first column of the submatrix
A
, respectively.
desca
(global and local)
INTEGER
array of size
dlen_
. The array descriptor for the distributed matrix
A
.
work
(local)
REAL
for
pstzrzf
DOUBLE PRECISION
for
pdtzrzf
.
COMPLEX
for
pctzrzf
.
DOUBLE COMPLEX
for
pztzrzf
.
Workspace array of size of
lwork
.
lwork
(local or global)
INTEGER
,
size of
work
, must be at least
lwork
mb_a*
(
mp
0+
nq
0+
mb_a
)
, where
iroff
=
mod
(
ia
-1,
mb_a
)
,
icoff
=
mod
(
ja
-1,
nb_a
)
,
iarow
=
indxg2p
(
ia
,
mb_a
,
MYROW
,