Contents

# symm

Computes a matrix-matrix product where one input matrix is symmetric and one matrix is general.

## Description

The
symm
routines compute a scalar-matrix-matrix product and add the result to a scalar-matrix product, where one of the matrices in the multiplication is symmetric. The argument
left_right
determines if the symmetric matrix
A
is on the left of the multiplication (
left_right
=
side::left
) or on the right (
left_right
=
side::right
). The operation is defined as:
If (
left_right
=
side::left
),
If (
left_right
=
side::right
),
where:
• alpha
and
beta
are scalars
• A
is either
m
x
m
or
n
x
n
symmetric matrix
• B
and
C
are
m
x
n
matrices
symm
supports the following precisions:
T
float
double
std::complex<float>
std::complex<double>

## symm (Buffer Version)

Syntax
``````namespace oneapi::mkl::blas::column_major {
void symm(sycl::queue &queue,
oneapi::mkl::side left_right,
oneapi::mkl::uplo upper_lower,
std::int64_t m,
std::int64_t n,
T alpha,
sycl::buffer<T,1> &a,
std::int64_t lda,
sycl::buffer<T,1> &b,
std::int64_t ldb,
T beta,
sycl::buffer<T,1> &c,
std::int64_t ldc)
}``````
``````namespace oneapi::mkl::blas::row_major {
void symm(sycl::queue &queue,
oneapi::mkl::side left_right,
oneapi::mkl::uplo upper_lower,
std::int64_t m,
std::int64_t n,
T alpha,
sycl::buffer<T,1> &a,
std::int64_t lda,
sycl::buffer<T,1> &b,
std::int64_t ldb,
T beta,
sycl::buffer<T,1> &c,
std::int64_t ldc)
}``````
Input Parameters
queue
The queue where the routine should be executed.
left_right
Specifies whether matrix
A
is on the left side or right side of the multiplication. See Data Types for more details.
upper_lower
Specifies whether matrix
A
is upper or lower triangular. See Data Types for more details.
m
Number of rows of matrix
B
and matrix
C
. Must be at least zero.
n
Number of columns of matrix
B
and matrix
C
. Must be at least zero.
alpha
Scaling factor for matrix-matrix product.
a
Buffer holding input matrix
A
. Size of the buffer must be at least
lda
*
m
if
left_right
=
side::left
or
lda
*
n
if
left_right
=
side::right
. See Matrix Storage for more details.
lda
A
. Must be at least
m
if
left_right
=
side::left
or at least
n
if
left_right
=
side::right
. Must be positive.
b
Buffer holding input matrix
B
. Size of the buffer must be at least
ldb
*
n
if column major layout or at least
ldb
*
m
if row major layout is used. See Matrix Storage for more details.
ldb
B
. Must be at least
m
if column major layout or at least
n
if row major layout is used. Must be positive.
beta
Scaling factor for matrix
C
.
c
Buffer holding input/output matrix
C
. Size of the buffer must be at least
ldc
*
n
if column major layout or at least
ldc
*
m
if row major layout is used. See Matrix Storage for more details.
ldc
C
. Must be at least
m
if column major layout or at least
n
if row major layout is used. Must be positive.
Output Parameters
c
Output buffer overwritten by
alpha
*
A
*
B
+
beta
*
C
if
left_right
=
side::left
or
alpha
*
B
*
A
+
beta
*
C
if
left_right
=
side::right
.
If
beta
= 0, matrix
C
does not need to be initialized before calling
symm
.

## symm (USM Version)

Syntax
``````namespace oneapi::mkl::blas::column_major {
sycl::event symm(sycl::queue &queue,
oneapi::mkl::side left_right,
oneapi::mkl::uplo upper_lower,
std::int64_t m,
std::int64_t n,
T alpha,
const T* a,
std::int64_t lda,
const T* b,
std::int64_t ldb,
T beta,
T* c,
std::int64_t ldc,
const std::vector<sycl::event> &dependencies = {})
}``````
``````namespace oneapi::mkl::blas::row_major {
sycl::event symm(sycl::queue &queue,
oneapi::mkl::side left_right,
oneapi::mkl::uplo upper_lower,
std::int64_t m,
std::int64_t n,
T alpha,
const T* a,
std::int64_t lda,
const T* b,
std::int64_t ldb,
T beta,
T* c,
std::int64_t ldc,
const std::vector<sycl::event> &dependencies = {})
}``````
Input Parameters
queue
The queue where the routine should be executed.
left_right
Specifies whether matrix
A
is on the left side or right side of the multiplication. See Data Types for more details.
upper_lower
Specifies whether matrix
A
is upper or lower triangular. See Data Types for more details.
m
Number of rows of matrix
B
and matrix
C
. Must be at least zero.
n
Number of columns of matrix
B
and matrix
C
. Must be at least zero.
alpha
Scaling factor for matrix-matrix product.
a
Pointer to input matrix
A
. Size of the array must be at least
lda
*
m
if
left_right
=
side::left
or
lda
*
n
if
left_right
=
side::right
. See Matrix Storage for more details.
lda
A
. Must be at least
m
if
left_right
=
side::left
or at least
n
if
left_right
=
side::right
. Must be positive.
b
Pointer to input matrix
B
. Size of the array must be at least
ldb
*
n
if column major layout or at least
ldb
*
m
if row major layout is used. See Matrix Storage for more details.
ldb
B
. Must be at least
m
if column major layout or at least
n
if row major layout is used. Must be positive.
beta
Scaling factor for matrix
C
.
c
Pointer to input/output matrix
C
. Size of the array must be at least
ldc
*
n
if column major layout or at least
ldc
*
m
if row major layout is used. See Matrix Storage for more details.
ldc
C
. Must be at least
m
if column major layout or at least
n
if row major layout is used. Must be positive.
dependencies
List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.
Output Parameters
c
Pointer to output matrix overwritten by
alpha
*
A
*
B
+
beta
*
C
if
left_right
=
side::left
or
alpha
*
B
*
A
+
beta
*
C
if
left_right
=
side::right
.
If
beta
= 0, matrix
C
does not need to be initialized before calling
symm
.
Return Values
Output event to wait on to ensure computation is complete.

#### Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.