hbmv

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

Syntax

void hbmv(queue &exec_queue, uplo upper_lower, std::int64_t n, std::int64_t k, T alpha, buffer<T, 1> &a, std::int64_t lda, buffer<T, 1> &x, std::int64_t incx, T beta, buffer<T, 1> &y, std::int64_t incy)

hbmv supports the following precisions and devices.

T

Devices Supported

std::complex<float>

Host, CPU, and GPU

std::complex<double>

Host, CPU, and GPU

Description

The hbmv routines compute a scalar-matrix-vector product and add the result to a scalar-vector product, with a Hermitian band matrix. The operation is defined as

y <- alpha*A*x + beta*y

where:

alpha and beta are scalars,

A is an n-by-n Hermitian band matrix, with k super-diagonals,

x and y are vectors of length n.

Input Parameters

exec_queue

The queue where the routine should be executed.

upper_lower

Specifies whether A is upper or lower triangular. See Data Types for more details.

n

Number of rows and columns of A. Must be at least zero.

k

Number of super-diagonals of the matrix A. Must be at least zero.

alpha

Scaling factor for the matrix-vector product.

a

Buffer holding input matrix A. Must have size at least lda*n. See Matrix and Vector Storage for more details.

lda

Leading dimension of matrix A. Must be at least (k + 1), and positive.

x

Buffer holding input vector x. The buffer must be of size at least (1 + (n - 1)*abs(incx)). See Matrix and Vector Storage for more details.

incx

Stride of vector x.

beta

Scaling factor for vector y.

y

Buffer holding input/output vector y. The buffer must be of size at least (1 + (n - 1)*abs(incy)). See Matrix and Vector Storage for more details.

incy

Stride of vector y.

Output Parameters

y

Buffer holding the updated vector y.