spr

Performs a rank-1 update of a symmetric packed matrix.

Description

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

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

where:

alpha is scalar,

A is an n-by-n symmetric matrix, supplied in packed form,

x is a vector of length n.

spr supports the following precisions.

T

float

double

spr (Buffer Version)

Syntax

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

Input Parameters

queue

The queue where the routine should be executed.

upper_lower

Specifies whether A is upper or lower triangular. See oneMKL defined datatypes for more details.

n

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

alpha

Scaling factor for the matrix-vector product.

x

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

incx

Stride of vector x.

a

Buffer holding input matrix A. Must have size at least (n*(n + 1))/2. See Matrix Storage for more details.

Output Parameters

a

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

spr (USM Version)

Syntax

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

Input Parameters

queue

The queue where the routine should be executed.

upper_lower

Specifies whether A is upper or lower triangular. See oneMKL defined datatypes for more details.

n

Number of rows and 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 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 (n*(n + 1))/2. See Matrix Storage for more details.

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 triangular part of the symmetric matrix A if upper_lower=upper, or the 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.

Parent topic: BLAS Level 2 Routines