.. SPDX-FileCopyrightText: 2019-2020 Intel Corporation .. .. SPDX-License-Identifier: CC-BY-4.0 .. _onemkl_blas_spr2: spr2 ==== Computes a rank-2 update of a symmetric packed matrix. .. _onemkl_blas_spr2_description: .. rubric:: Description The ``spr2`` routines compute two scalar-vector-vector products and add them to a symmetric packed matrix. The operation is defined as: .. math:: A \leftarrow alpha*x*y^T + alpha*y*x^T + A where: ``alpha`` is scalar, ``A`` is an ``n``-by-``n`` symmetric matrix, supplied in packed form, ``x`` and ``y`` are vectors of length ``n``. ``spr`` supports the following precisions. .. list-table:: :header-rows: 1 * - T * - ``float`` * - ``double`` .. _onemkl_blas_spr2_buffer: spr2 (Buffer Version) --------------------- .. rubric:: Syntax .. code-block:: cpp namespace oneapi::mkl::blas::column_major { void spr2(sycl::queue &queue, onemkl::uplo upper_lower, std::int64_t n, T alpha, sycl::buffer &x, std::int64_t incx, sycl::buffer &y, std::int64_t incy, sycl::buffer &a) } .. code-block:: cpp namespace oneapi::mkl::blas::row_major { void spr2(sycl::queue &queue, onemkl::uplo upper_lower, std::int64_t n, T alpha, sycl::buffer &x, std::int64_t incx, sycl::buffer &y, std::int64_t incy, sycl::buffer &a) } .. container:: section .. rubric:: Input Parameters queue The queue where the routine should be executed. upper_lower Specifies whether ``A`` is upper or lower triangular. See :ref:`onemkl_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 :ref:`matrix-storage` for more details. incx Stride of vector ``x``. y Buffer holding input/output vector ``y``. The buffer must be of size at least (1 + (``n`` - 1)*abs(``incy``)). See :ref:`matrix-storage` for more details. incy Stride of vector ``y``. a Buffer holding input matrix ``A``. Must have size at least (``n``\ \*(``n``-1))/2. See :ref:`matrix-storage` for more details. .. container:: section .. rubric:: 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``. .. container:: section .. rubric:: Throws This routine shall throw the following exceptions if the associated condition is detected. An implementation may throw additional implementation-specific exception(s) in case of error conditions not covered here. :ref:`oneapi::mkl::invalid_argument` :ref:`oneapi::mkl::unsupported_device` :ref:`oneapi::mkl::host_bad_alloc` :ref:`oneapi::mkl::device_bad_alloc` :ref:`oneapi::mkl::unimplemented` .. _onemkl_blas_spr2_usm: spr2 (USM Version) ------------------ .. rubric:: Syntax .. code-block:: cpp namespace oneapi::mkl::blas::column_major { sycl::event spr2(sycl::queue &queue, onemkl::uplo upper_lower, std::int64_t n, T alpha, const T *x, std::int64_t incx, const T *y, std::int64_t incy, T *a) } .. code-block:: cpp namespace oneapi::mkl::blas::row_major { sycl::event spr2(sycl::queue &queue, onemkl::uplo upper_lower, std::int64_t n, T alpha, const T *x, std::int64_t incx, const T *y, std::int64_t incy, T *a) } .. container:: section .. rubric:: Input Parameters queue The queue where the routine should be executed. upper_lower Specifies whether ``A`` is upper or lower triangular. See :ref:`onemkl_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 :ref:`matrix-storage` for more details. incx Stride of vector ``x``. y Pointer to input/output vector ``y``. The array holding input/output vector ``y`` must be of size at least (1 + (``n`` - 1)*abs(``incy``)). See :ref:`matrix-storage` for more details. incy Stride of vector ``y``. a Pointer to input matrix ``A``. The array holding input matrix ``A`` must have size at least (``n``\ \*(``n``-1))/2. See :ref:`matrix-storage` for more details. dependencies List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies. .. container:: section .. rubric:: 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``. .. container:: section .. rubric:: Return Values Output event to wait on to ensure computation is complete. .. container:: section .. rubric:: Throws This routine shall throw the following exceptions if the associated condition is detected. An implementation may throw additional implementation-specific exception(s) in case of error conditions not covered here. :ref:`oneapi::mkl::invalid_argument` :ref:`oneapi::mkl::unsupported_device` :ref:`oneapi::mkl::host_bad_alloc` :ref:`oneapi::mkl::device_bad_alloc` :ref:`oneapi::mkl::unimplemented` **Parent topic:** :ref:`blas-level-2-routines`