gemv#
Computes a matrix-vector product using a general matrix.
Description
The gemv
routines compute a scalar-matrix-vector product and add the
result to a scalar-vector product, with a general matrix. The
operation is defined as:
where:
op(A
) is one of op(A
) = A
, or op(A
) =
A
T, or op(A
) = A
H,
alpha
and beta
are scalars,
A
is an m
-by-n
matrix, and x
, y
are vectors.
gemv
supports the following precisions.
T
float
double
std::complex<float>
std::complex<double>
gemv (Buffer Version)#
Syntax
namespace oneapi::mkl::blas::column_major {
void gemv(sycl::queue &queue,
onemkl::transpose trans,
std::int64_t m,
std::int64_t n,
T alpha,
sycl::buffer<T,1> &a,
std::int64_t lda,
sycl::buffer<T,1> &x,
std::int64_t incx,
T beta,
sycl::buffer<T,1> &y,
std::int64_t incy)
}
namespace oneapi::mkl::blas::row_major {
void gemv(sycl::queue &queue,
onemkl::transpose trans,
std::int64_t m,
std::int64_t n,
T alpha,
sycl::buffer<T,1> &a,
std::int64_t lda,
sycl::buffer<T,1> &x,
std::int64_t incx,
T beta,
sycl::buffer<T,1> &y,
std::int64_t incy)
}
Input Parameters
- queue
The queue where the routine should be executed.
- trans
Specifies
op(A)
, the transposition operation applied toA
.- m
Specifies the number of rows of the matrix
A
. The value ofm
must be at least zero.- n
Specifies the number of columns of the matrix
A
. The value ofn
must be at least zero.- alpha
Scaling factor for the matrix-vector product.
- a
The buffer holding the input matrix
A
. Must have a size of at leastlda
*n
if column major layout is used or at leastlda
*m
if row major layout is used. See Matrix Storage for more details.- lda
Leading dimension of matrix
A
. Must be positive and at leastm
if column major layout is used or at leastn
if row major layout is used.- x
Buffer holding input vector
x
. The lengthlen
of vectorx
isn
ifA
is not transposed, andm
ifA
is transposed. The buffer must be of size at least (1 + (len
- 1)*abs(incx
)). See Matrix Storage for more details.- incx
The stride of vector
x
.- beta
The scaling factor for vector
y
.- y
Buffer holding input/output vector
y
. The lengthlen
of vectory
ism
, ifA
is not transposed, andn
ifA
is transposed. The buffer must be of size at least (1 + (len
- 1)*abs(incy
)) wherelen
is this length. See Matrix Storage for more details.- incy
The stride of vector
y
.
Output Parameters
- y
The buffer holding updated vector
y
.
gemv (USM Version)#
Syntax
namespace oneapi::mkl::blas::column_major {
sycl::event gemv(sycl::queue &queue,
onemkl::transpose trans,
std::int64_t m,
std::int64_t n,
T alpha,
const T *a,
std::int64_t lda,
const T *x,
std::int64_t incx,
T beta,
T *y,
std::int64_t incy,
const std::vector<sycl::event> &dependencies = {})
}
namespace oneapi::mkl::blas::row_major {
sycl::event gemv(sycl::queue &queue,
onemkl::transpose trans,
std::int64_t m,
std::int64_t n,
T alpha,
const T *a,
std::int64_t lda,
const T *x,
std::int64_t incx,
T beta,
T *y,
std::int64_t incy,
const std::vector<sycl::event> &dependencies = {})
}
Input Parameters
- queue
The queue where the routine should be executed.
- trans
Specifies
op(A)
, the transposition operation applied toA
. See oneMKL Defined Datatypes for more details.- m
Specifies the number of rows of the matrix
A
. The value ofm
must be at least zero.- n
Specifies the number of columns of the matrix
A
. The value ofn
must be at least zero.- alpha
Scaling factor for the matrix-vector product.
- a
Pointer to the input matrix
A
. Must have a size of at leastlda
*n
if column major layout is used or at leastlda
*m
if row major layout is used. See Matrix Storage for more details.- lda
Leading dimension of matrix
A
. Must be positive and at leastm
if column major layout is used or at leastn
if row major layout is used.- x
Pointer to the input vector
x
. The lengthlen
of vectorx
isn
ifA
is not transposed, andm
ifA
is transposed. The array holding vectorx
must be of size at least (1 + (len
- 1)*abs(incx
)). See Matrix Storage for more details.- incx
The stride of vector
x
.- beta
The scaling factor for vector
y
.- y
Pointer to input/output vector
y
. The lengthlen
of vectory
ism
, ifA
is not transposed, andn
ifA
is transposed. The array holding input/output vectory
must be of size at least (1 + (len
- 1)*abs(incy
)) wherelen
is this length. See Matrix Storage for more details.- incy
The stride of vector
y
.- dependencies
List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.
Output Parameters
- y
The pointer to updated vector
y
.
Return Values
Output event to wait on to ensure computation is complete.
Parent topic: BLAS Level 2 Routines