syr2k¶

Performs a symmetric rank-2k update.

syr2k supports the following precisions:

T

float

double

std::complex<float>

std::complex<double>

Description

The syr2k routines perform a rank-2k update of an n x n symmetric matrix C by general matrices A and B. If trans = transpose::nontrans, the operation is defined as:

C <- alpha*(A*B ^T + B*A ^T) + beta*C

where A is n x k and B is k x n.

If trans = transpose::trans, the operation is defined as:

C <- alpha*(A ^T * B + B ^T * A) + beta * C

where A is k x n and B is n x k.

In both cases:

alpha and beta are scalars,

C is a symmetric matrix and A,B are general matrices,

The inner dimension of both matrix multiplications is k.

syr2k (Buffer Version)¶

Syntax

void onemkl::blas::syr2k(sycl::queue &queue, onemkl::uplo upper_lower, onemkl::transpose trans, std::int64_t n, std::int64_t k, T alpha, sycl::buffer<T, 1> &a, std::int64_t lda, sycl::buffer<T, 1> &b, std::int64_t ldb, T beta, sycl::buffer<T, 1> &c, std::int64_t ldc)¶

Input Parameters

queue: The queue where the routine should be executed.
upper_lower: Specifies whether A’s data is stored in its upper or lower triangle. See oneMKL defined datatypes for more details.
trans: Specifies the operation to apply, as described above. Conjugation is never performed, even if trans = transpose::conjtrans.
n: Number of rows and columns in C.The value of n must be at least zero.
k: Inner dimension of matrix multiplications.The value of k must be at least zero.
alpha: Scaling factor for the rank-2k update.
a: Buffer holding input matrix A. If A is not transposed, A is an m-by-k matrix so the array a must have size at least lda*k. If A is transposed, A is an k-by-m matrix so the array a must have size at least lda*m. See Matrix and Vector Storage for more details.
lda: Leading dimension of A. Must be at least n if trans = transpose::nontrans, and at least k otherwise. Must be positive.
b: Buffer holding input matrix B. If trans = transpose::nontrans, B is an k-by-n matrix so the array b must have size at least ldb*n. Otherwise, B is an n-by-k matrix so the array b must have size at least ldb*k. See Matrix and Vector Storage for more details.
ldb: Leading dimension of B. Must be at least k if trans = transpose::nontrans, and at least n otherwise. Must be positive.
beta: Scaling factor for matrix C.
c: Buffer holding input/output matrix C. Must have size at least ldc*n. See Matrix and Vector Storage for more details
ldc: Leading dimension of C. Must be positive and at least n.

Output Parameters

c: Output buffer, overwritten by the updated C matrix.

syr2k (USM Version)¶

Syntax

sycl::event onemkl::blas::syr2k(sycl::queue &queue, onemkl::uplo upper_lower, onemkl::transpose trans, std::int64_t n, std::int64_t k, T alpha, const T *a, std::int64_t lda, const T *b, std::int64_t ldb, T beta, T *c, std::int64_t ldc, const sycl::vector_class<sycl::event> &dependencies = {})¶

Input Parameters

queue: The queue where the routine should be executed.
upper_lower: Specifies whether A’s data is stored in its upper or lower triangle. See oneMKL defined datatypes for more details.
trans: Specifies the operation to apply, as described above. Conjugation is never performed, even if trans = transpose::conjtrans.
n: Number of rows and columns in C. The value of n must be at least zero.
k: Inner dimension of matrix multiplications.The value of k must be at least zero.
alpha: Scaling factor for the rank-2k update.
a: Pointer to input matrix A. If A is not transposed, A is an m-by-k matrix so the array a must have size at least lda*k. If A is transposed, A is an k-by-m matrix so the array a must have size at least lda*m. See Matrix and Vector Storage for more details.
lda: Leading dimension of A. Must be at least n if trans = transpose::nontrans, and at least k otherwise. Must be positive.
b: Pointer to input matrix B. If trans = transpose::nontrans, B is an k-by-n matrix so the array b must have size at least ldb*n. Otherwise, B is an n-by-k matrix so the array b must have size at least ldb*k. See Matrix and Vector Storage for more details.
ldb: Leading dimension of B. Must be at least k if trans = transpose::nontrans, and at least n otherwise. Must be positive.
beta: Scaling factor for matrix C.
c: Pointer to input/output matrix C. Must have size at least ldc*n. See Matrix and Vector Storage for more details
ldc: Leading dimension of C. Must be positive and at least n.
dependencies: List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.

Output Parameters

c: Pointer to the output matrix, overwritten by the updated C matrix.

Return Values

Output event to wait on to ensure computation is complete.

Parent topic: BLAS Level 3 Routines