gemv¶

Computes a matrix-vector product using a general matrix.

gemv supports the following precisions.

T

float

double

std::complex<float>

std::complex<double>

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

y <- alpha*op(A)*x + beta*y

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 (Buffer Version)¶

Syntax

void onemkl::blas::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 to A.
m: Specifies the number of rows of the matrix A. The value of m must be at least zero.
n: Specifies the number of columns of the matrix A. The value of n 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 least lda*``n``. See Matrix and Vector Storage for more details.
lda: The leading dimension of matrix A. It must be at least m, and positive.
x: Buffer holding input vector x. The length len of vector x is n if A is not transposed, and m if A is transposed. The buffer must be of size at least (1 + (len - 1)*abs(incx)). See Matrix and Vector 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 length len of vector y is m, if A is not transposed, and n if A is transposed. The buffer must be of size at least (1 + (len - 1)*abs(incy)) where len is this length. See Matrix and Vector Storage for more details.
incy: The stride of vector y.

Output Parameters

y: The buffer holding updated vector y.

gemv (USM Version)¶

Syntax

sycl::event onemkl::blas::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 sycl::vector_class<sycl::event> &dependencies = {})¶

Input Parameters

queue: The queue where the routine should be executed.
trans: Specifies op(A), the transposition operation applied to A. See oneMKL defined datatypes for more details.
m: Specifies the number of rows of the matrix A. The value of m must be at least zero.
n: Specifies the number of columns of the matrix A. The value of n must be at least zero.
alpha: Scaling factor for the matrix-vector product.
a: The pointer to the input matrix A. Must have a size of at least lda*``n``. See Matrix and Vector Storage for more details.
lda: The leading dimension of matrix A. It must be at least m, and positive.
x: Pointer to the input vector x. The length len of vector x is n if A is not transposed, and m if A is transposed. The array holding vector x must be of size at least (1 + (len - 1)*abs(incx)). See Matrix and Vector 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 length len of vector y is m, if A is not transposed, and n if A is transposed. The array holding input/output vector y must be of size at least (1 + (len - 1)*abs(incy)) where len is this length. See Matrix and Vector 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