Contents

syr

Computes a rank-1 update of a symmetric matrix.

Description

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

A \leftarrow alpha*x*x^T + A

where:

  • alpha is scalar

  • A is n x n symmetric matrix

  • x is a vector of length n

syr supports the following precisions:

T

float

double

syr (Buffer Version)

Syntax

namespace oneapi::mkl::blas::column_major {
    void syr(sycl::queue &queue,
             oneapi::mkl::uplo upper_lower,
             std::int64_t n,
             T alpha,
             sycl::buffer<T,1> &x,
             std::int64_t incx,
             sycl::buffer<T,1> &a,
             std::int64_t lda)
}

namespace oneapi::mkl::blas::row_major {
    void syr(sycl::queue &queue,
             oneapi::mkl::uplo upper_lower,
             std::int64_t n,
             T alpha,
             sycl::buffer<T,1> &x,
             std::int64_t incx,
             sycl::buffer<T,1> &a,
             std::int64_t lda)
}

Input Parameters

queue

The queue where the routine should be executed.

upper_lower

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

n

Number of columns of matrix A. Must be at least zero.

alpha

Scaling factor for the matrix-vector product.

x

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

incx

Stride of vector x.

a

Buffer holding input matrix A. Size of the buffer must be at least lda * n. See Matrix Storage for more details.

lda

Leading dimension of matrix A. Must be at least n and positive.

Output Parameters

a

Buffer holding updated upper triangular part of the symmetric matrix A if upper_lower=upper or updated lower triangular part of the symmetric matrix A if upper_lower=lower.

syr (USM Version)

Syntax

namespace oneapi::mkl::blas::column_major {
    sycl::event syr(sycl::queue &queue,
                    oneapi::mkl::uplo upper_lower,
                    std::int64_t n,
                    T alpha,
                    const T *x,
                    std::int64_t incx,
                    T *a,
                    std::int64_t lda,
                    const std::vector<sycl::event> &dependencies = {})
}

namespace oneapi::mkl::blas::row_major {
    sycl::event syr(sycl::queue &queue,
                    oneapi::mkl::uplo upper_lower,
                    std::int64_t n,
                    T alpha,
                    const T *x,
                    std::int64_t incx,
                    T *a,
                    std::int64_t lda,
                    const std::vector<sycl::event> &dependencies = {})
}

Input Parameters

queue

The queue where the routine should be executed.

upper_lower

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

n

Number of columns of matrix A. Must be at least zero.

alpha

Scaling factor for the matrix-vector product.

x

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

incx

Stride of vector x.

a

Pointer to input matrix A. Size of the array holding input matrix A must be at least lda * n. See Matrix 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 updated upper triangular part of the symmetric matrix A if upper_lower=upper or updated lower triangular part of the symmetric matrix A if upper_lower=lower.

Return Values

Output event to wait on to ensure computation is complete.

symv syr2