Developer Reference

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

?her2k

Performs a Hermitian rank-2k update.

Syntax

call cher2k
(
uplo
,
trans
,
n
,
k
,
alpha
,
a
,
lda
,
b
,
ldb
,
beta
,
c
,
ldc
)
call zher2k
(
uplo
,
trans
,
n
,
k
,
alpha
,
a
,
lda
,
b
,
ldb
,
beta
,
c
,
ldc
)
call her2k
(
a
,
b
,
c
[
,
uplo
]
[
,
trans
]
[
,
alpha
]
[
,
beta
]
)
Include Files
  • mkl.fi
    ,
    blas.f90
Description
The
?her2k
routines perform a rank-2k
matrix-matrix operation using general matrices
A
and
B
and a Hermitian matrix
C
.
The operation is defined as
C
:=
alpha
*
A
*
B
H
+ conjg(
alpha
)
B
*
A
H
+
beta
*C
or
C
:=
alpha
*
A
H
*
B
+ conjg(
alpha
)*
B
H
*
A
+
beta
*C
where:
alpha
is a scalar and
beta
is a real scalar.
C
is an
n
-by-
n
Hermitian matrix.
A
and
B
are
n
-by-
k
matrices in the first case and
k
-by-
n
matrices 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 of the array
c
is used.
If
uplo
=
'L'
or
'l'
, then the low triangular of the array
c
is used.
trans
CHARACTER*1
.
Specifies the operation:
if
trans
= 'N'
or
'n'
, then
C
:=
alpha
*
A
*
B
H
+
alpha
*
B
*
A
H
+
beta
*
C
;
if
trans
= 'C'
or
'c'
, then
C
:=
alpha
*
A
H
*
B
+
alpha
*
B
H
*
A
+
beta
*
C
.