Developer Reference

  • 098
  • 03/30/2020
  • Public Content
Contents

p?geqrf

Computes the
QR
factorization of a general m-by-n matrix.

Syntax

call psgeqrf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
call pdgeqrf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
call pcgeqrf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
call pzgeqrf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
Include Files
Description
The
p?geqrf
routine
forms the
QR
factorization of a general
m
-by-
n
distributed matrix sub(
A
)=
A
(
ia
:
ia
+
m
-1,
ja
:
ja
+
n
-1) as
A
=
Q
*
R
.
Input Parameters
m
(global)
INTEGER
.
The number of rows in the distributed matrix sub(
A
);
(
m
0)
.
n
(global)
INTEGER
.
The number of columns in the distributed matrix sub(
A
);
(
n
0)
.
a
(local)
REAL
for
psgeqrf
DOUBLE PRECISION
for
pdgeqrf
COMPLEX
for
pcgeqrf
DOUBLE COMPLEX
for
pzgeqrf
.
Pointer into the local memory to an array of local size
(
lld_a
,
LOCc
(
ja
+
n
-1))
.
Contains the local pieces of the 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
(
ia
:
ia
+
m
-1,
ja
:
ja
+
n
-1), respectively.
desca
(global and local)
INTEGER
array of size
dlen_
. The array descriptor for the distributed matrix
A
work
(local).
REAL
for
psgeqrf
DOUBLE PRECISION
for
pdgeqrf
.
COMPLEX
for
pcgeqrf
.
DOUBLE COMPLEX
for
pzgeqrf
Workspace array of size
lwork
.
lwork
(local or global)
INTEGER
,
size of
work
, must be at least
lwork
nb_a
* (
mp
0+
nq
0+
nb_a
)
, where
iroff
=
mod
(
ia
-1,
mb_a
),
icoff
=
mod
(
ja
-1,
nb_a
)
,
iarow
=
indxg2p
(
ia
,
mb_a