.. _onemkl_blas_dotu:

dotu
====

Computes the dot product of two complex vectors.

Description
***********

The ``dotu`` routines perform a dot product between two complex vectors. 
The operation is defined as:

.. math::

      \mathrm{result} = \sum_{i=1}^n X_i Y_i

``dotu`` supports the following precisions:

.. list-table::
   :header-rows: 1

   * -  T
   * -  ``std::complex<float>``
   * -  ``std::complex<double>``


dotu (Buffer Version)
*********************

Syntax
------

.. code-block:: cpp

   namespace oneapi::mkl::blas::column_major {
       void dotu(sycl::queue &queue,
                 std::int64_t n,
                 sycl::buffer<T,1> &x,
                 std::int64_t incx,
                 sycl::buffer<T,1> &y,
                 std::int64_t incy,
                 sycl::buffer<T,1> &result)
   }

.. code-block:: cpp

   namespace oneapi::mkl::blas::row_major {
       void dotu(sycl::queue &queue,
                 std::int64_t n,
                 sycl::buffer<T,1> &x,
                 std::int64_t incx,
                 sycl::buffer<T,1> &y,
                 std::int64_t incy,
                 sycl::buffer<T,1> &result)
   }

Input Parameters
----------------

queue
   The queue where the routine should be executed.

n
   Number of elements in vectors ``x`` and ``y``.

x
   Buffer holding input vector ``x``. Size of the buffer must be at
   least (1 + (``n`` - 1)*abs(``incx``)). See :ref:`matrix-storage` for
   more details.

incx
   Stride of vector ``x``.

y
   Buffer holding input vector ``y``. The buffer must have size at least (1 + (``n`` - 1)*abs(``incy``)). 
   See :ref:`matrix-storage` for more details.

incy
   Stride of vector ``y``.

Output Parameters
-----------------

result
   Buffer where the result (a scalar) is stored.


dotu (USM Version)
******************

Syntax
------

.. code-block:: cpp

   namespace oneapi::mkl::blas::column_major {
       sycl::event dotu(sycl::queue &queue,
                        std::int64_t n,
                        const T *x,
                        std::int64_t incx,
                        const T *y,
                        std::int64_t incy,
                        T *result,
                        const std::vector<sycl::event> &dependencies = {})
   }

.. code-block:: cpp

   namespace oneapi::mkl::blas::row_major {
       sycl::event dotu(sycl::queue &queue,
                        std::int64_t n,
                        const T *x,
                        std::int64_t incx,
                        const T *y,
                        std::int64_t incy,
                        T *result,
                        const std::vector<sycl::event> &dependencies = {})
   }

Input Parameters
----------------

queue
   The queue where the routine should be executed.

n
   Number of elements in vectors ``x`` and ``y``.

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

incx
   Stride of vector ``x``.

y
   Pointer to input vector ``y``. Size of the array holding input vector
   ``y`` must be at least (1 + (``n`` - 1)*abs(``incy``)). See :ref:`matrix-storage` for more details.

incy
   Stride of vector ``y``.

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

Output Parameters
-----------------

result
   Pointer to where the result (a scalar) is stored.

Return Values
-------------

Output event to wait on to ensure computation is complete.