syr (USM Version)

Computes a rank-1 update of a symmetric matrix.

Syntax

event syr(queue &exec_queue, uplo upper_lower, std::int64_t n, T alpha, const T *x, std::int64_t incx, T *a, std::int64_t lda, const vector_class<event> &dependencies = {})

The USM version of syr supports the following precisions and devices.

T

Devices Supported

float

Host, CPU, and GPU

double

Host, CPU, and GPU

Description

The syr routines compute a scalar-vector-vector product add them and add the result to a matrix, with a symmetric matrix. The operation is defined as

A  <- alpha*x*xT + A

where:

alpha is scalar,

A is an n-by-n symmetric matrix,

x is a vector 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 columns of A. Must be at least zero.

alpha

Scaling factor for the matrix-vector product.

x

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

incx

Stride of vector x.

a

Pointer to input matrix A. The array 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 n, and positive.

dependencies

List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.

Output Parameters

a

Pointer to the updated upper triangularpart of the symmetric matrix A if upper_lower =upper or the updated lower triangular part of thesymmetric matrix A if upper_lower =lower.

Return Values

Output event to wait on to ensure computation is complete.