Developer Reference

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

?syrk

Performs a symmetric rank-k update.

Syntax

call ssyrk
(
uplo
,
trans
,
n
,
k
,
alpha
,
a
,
lda
,
beta
,
c
,
ldc
)
call dsyrk
(
uplo
,
trans
,
n
,
k
,
alpha
,
a
,
lda
,
beta
,
c
,
ldc
)
call csyrk
(
uplo
,
trans
,
n
,
k
,
alpha
,
a
,
lda
,
beta
,
c
,
ldc
)
call zsyrk
(
uplo
,
trans
,
n
,
k
,
alpha
,
a
,
lda
,
beta
,
c
,
ldc
)
call syrk
(
a
,
c
[
,
uplo
]
[
,
trans
]
[
,
alpha
]
[
,
beta
]
)
Include Files
  • mkl.fi
    ,
    blas.f90
Description
The
?syrk
routines perform a rank-k
matrix-matrix operation for a symmetric matrix
C
using a general matrix
A
. The operation is defined as:
C
:=
alpha
*
A
*
A
' +
beta
*
C
,
or
C
:=
alpha
*
A
'*
A
+
beta
*
C
,
where:
alpha
and
beta
are scalars,
C
is an
n
-by-
n
symmetric matrix,
A
is an
n
-by-
k
matrix in the first case and a
k
-by-
n
matrix in the second case.
Input Parameters
uplo
CHARACTER*1
.
Specifies whether the upper or lower triangular part of the array
c
is used.
If
uplo
=
'U'
or
'u'
, then the upper triangular part of the array
c
is used.
If
uplo
=
'L'
or
'l'
, then the low triangular part of the array
c
is used.
trans
CHARACTER*1
.
Specifies the operation:
if
trans
= 'N'
or
'n'
, then
C
:=
alpha
*
A
*
A
' +
beta
*
C
;
if
trans
= 'T'
or
't'
, then
C
:=
alpha
*
A
'*
A
+
beta
*
C
;
if
trans
= 'C'
or
'c'
, then
C
:=
alpha
*
A
'*
A
+
beta
*
C
.
n
INTEGER
.
Specifies the order of the matrix
C
.
The value of
n
must be at least zero.
k
INTEGER
.
On entry with
trans
= 'N'