## Developer Reference

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

# ?hbmv

Computes a matrix-vector product using a Hermitian band matrix.

## Syntax

Include Files
• mkl.fi
,
blas.f90
Description
The
?hbmv
routines perform a matrix-vector operation defined as
y
:=
alpha
*
A
*
x
+
beta
*
y
,
where:
alpha
and
beta
are scalars,
x
and
y
are
n
-element vectors,
A
is an
n
-by-
n
Hermitian band matrix, with
k
super-diagonals.
Input Parameters
uplo
CHARACTER*1
.
Specifies whether the upper or lower triangular part of the Hermitian band matrix
A
is used:
If
uplo
=
'U'
or
'u'
, then the upper triangular part of the matrix
A
is used.
If
uplo
=
'L'
or
'l'
, then the low triangular part of the matrix
A
is used.
n
INTEGER
.
Specifies the order of the matrix
A
. The value of
n
must be at least zero.
k
INTEGER
.
For
uplo
=
'U'
or
'u'
Specifies the number of super-diagonals of the matrix
A
.
For
uplo
=
'L'
or
'l'
: Specifies the number of sub-diagonals of the matrix
A
.
The value of
k
must satisfy
0
k
.
alpha
COMPLEX
for
chbmv
DOUBLE COMPLEX
for
zhbmv
Specifies the scalar
alpha
.
a
COMPLEX
for
chbmv
DOUBLE COMPLEX
for
zhbmv
Array, size
(
lda
,
n
)
.
Before entry with
uplo
=
'U'
or
'u'
(
k
+ 1)
by
n
part of the array
a
must contain the upper triangular band part of the Hermitian matrix. The matrix must be supplied column-by-column,
with the leading diagonal of the matrix in row
(
k
+ 1)
of the array, the first super-diagonal starting at position 2 in row
k
, and so on.
The top left
k
by
k
triangle of the array
a
is not referenced.
The following program segment transfers the upper triangular part of a He