Developer Reference

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

?symv

Computes a matrix-vector product for a complex symmetric matrix.

Syntax

call csymv
(
uplo
,
n
,
alpha
,
a
,
lda
,
x
,
incx
,
beta
,
y
,
incy
)
call zsymv
(
uplo
,
n
,
alpha
,
a
,
lda
,
x
,
incx
,
beta
,
y
,
incy
)
Include Files
  • mkl.fi
Description
The routine performs the matrix-vector operation defined as
y
:=
alpha
*
a
*
x
+
beta
*
y
,
where:
alpha
and
beta
are complex scalars
x
and
y
are
n
-element complex vectors
a
is an
n
-by-
n
symmetric complex matrix.
These routines have their real equivalents in BLAS (see
?symv
in Chapter 
"BLAS and Sparse BLAS Routines"
).
Input Parameters
uplo
CHARACTER*1
. Specifies whether the upper or lower triangular part of the array
a
is used:
If
uplo
=
'U'
or
'u'
, then the upper triangular part of the array
a
is used.
If
uplo
=
'L'
or
'l'
, then the lower triangular part of the array
a
is used.
n
INTEGER
. Specifies the order of the matrix
a
. The value of
n
must be at least zero.
alpha
,
beta
COMPLEX
for
csymv
DOUBLE COMPLEX
for
zsymv
Specify the scalars
alpha
and
beta
. When
beta
is supplied as zero, then
y
need not be set on input.
a
COMPLEX
for
csymv
DOUBLE COMPLEX
for
zsymv
Array,
DIMENSION
(
lda
,
n
). Before entry with
uplo
=
'U'
or
'u'
, the leading
n
-by-
n
upper triangular part of the array
a
must contain the upper triangular part of the symmetric matrix and the strictly lower triangular part of
a
is not referenced. Before entry with
uplo
=
'L'
or
'l'
, the leading
n
-by-
n
lower triangular part of the array
a
must contain the lower triangular part of the symmetric matrix and the strictly upper triangular part of
a
is not referenced.
lda
INTEGER
. Specifies the leading dimension of
A
as declared in the calling (sub)program. The value of
lda
must be at least
max
(1,
n
)
.
x
COMPLEX
for
csymv
DOUBLE COMPLEX
for
zsymv
Array,
DIMENSION
at least
(1 + (
n
- 1)*abs(
incx
))
. Before entry, the incremented array
x
must contain the
n
-element vector
x
.
incx
INTEGER
. Specifies the increment for the elements of
x
. The value of
incx
must not be zero.
y
COMPLEX
for
csymv
DOUBLE COMPLEX
for
zsymv
Array,
DIMENSION
at least
(1 + (
n
- 1)*abs(
incy
))
. Before entry, the incremented arra