Developer Reference

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

p?gelqf

Computes the
LQ
factorization of a general rectangular matrix.

Syntax

call psgelqf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
call pdgelqf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
call pcgelqf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
call pzgelqf
(
m
,
n
,
a
,
ia
,
ja
,
desca
,
tau
,
work
,
lwork
,
info
)
Include Files
Description
The
p?gelqf
routine
computes the
LQ
factorization of a real/complex distributed
m
-by-
n
matrix sub(
A
)=
A
(
ia
:
ia
+
m
-1,
ja
:
ja
+
n
-1) =
L
*
Q
.
Input Parameters
m
(global)
INTEGER
.
The number of rows in the distributed submatrix sub(
A
)
(
m
0)
.
n
(global)
INTEGER
.
The number of columns in the distributed submatrix sub(
A
)
(
n
0)
.
a
(local)
REAL
for
psgelqf
DOUBLE PRECISION
for
pdgelqf
COMPLEX
for
pcgelqf
DOUBLE COMPLEX
for
pzgelqf
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 array
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
psgelqf
DOUBLE PRECISION
for
pdgelqf
COMPLEX
for
pcgelqf
DOUBLE COMPLEX
for
pzgelqf
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
,
rsrc_a
,
NPROW
)
,
iacol
=
indxg2p
(
ja
,