Developer Reference

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

p?lange

Returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element, of a general rectangular matrix.

Syntax

val
=
pslange
(
norm
,
m
,
n
,
a
,
ia
,
ja
,
desca
,
work
)
val
=
pdlange
(
norm
,
m
,
n
,
a
,
ia
,
ja
,
desca
,
work
)
val
=
pclange
(
norm
,
m
,
n
,
a
,
ia
,
ja
,
desca
,
work
)
val
=
pzlange
(
norm
,
m
,
n
,
a
,
ia
,
ja
,
desca
,
work
)
Description
The
p?lange
routine
returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a distributed matrix
sub(
A
) =
A
(
ia
:
ia
+
m
-1
,
ja
:
ja
+
n
-1)
.
Input Parameters
norm
(global)
CHARACTER
.
Specifies what value is returned by the
routine
:
=
'M'
or
'm':
val
=
max
(
abs
(
A
ij
))
, largest absolute value of the matrix
A
, it s not a matrix norm.
=
'1'
or
'O'
or
'o':
val
=
norm1
(
A
)
, 1-norm of the matrix
A
(maximum column sum),
=
'I'
or
'i':
val
=
normI
(
A
)
, infinity norm of the matrix
A
(maximum row sum),
=
'F'
,
'f'
,
'E'
or
'e':
val
=
normF
(
A
)
, Frobenius norm of the matrix
A
(square root of sum of squares).
m
(global)
INTEGER
.
The number of rows in the distributed matrix sub(A). When
m
= 0
,
p?lange
is set to zero.
m
0.
n
(global)
INTEGER
.
The number of columns in the distributed matrix sub(
A
). When
n
= 0
,
p?lange
is set to zero.
n
0.
a
(local).
REAL
for
pslange
DOUBLE PRECISION
for
pdlange
COMPLEX
for
pclange
COMPLEX*16
for
pzlange
.
Pointer into the local memory to an array of size
(
lld_a
,
LOCc
(
ja
+
n
-1))
containing the local pieces of the distributed matrix sub(
A
).
ia
,
ja
(global)
INTEGER
.
The row and column indices in the global matrix
A
indicating the first row and the first column of the matrix sub(
A
), respectively.
desca
(global and local)
INTEGER
array of size
dlen_
. The array descriptor for the distributed matrix A.
work
(local).
REAL
for
pslange
DOUBLE PRECISION
for
pdlange
COMPLEX
for
pclange
COMPLEX*16
for
pzlange
.
Array size
lwork
.
lwork
0
if
norm
=
'M'
or
'm'
(not referenced),
nq
0 if
norm
= '1'
,
'O'
or
'o'
,
mp
0 if
norm
=