.. _onemkl_blas_dot:

dot
===

Computes the dot product of two real vectors.

.. _onemkl_blas_dot_description:

.. rubric:: Description

The ``dot`` routines perform a dot product between two vectors:

.. math::

   result = \sum_{i=1}^{n}X_iY_i 

``dot`` supports the following precisions for data.

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

      * -  T 
        -  T_res 
      * -  ``float`` 
        -  ``float`` 
      * -  ``double`` 
        -  ``double`` 
      * -  ``float`` 
        -  ``double`` 

.. container:: Note

   .. rubric:: Note
      :class: NoteTipHead

   For the mixed precision version (inputs are float while result is
   double), the dot product is computed with double precision.

.. _onemkl_blas_dot_buffer:

dot (Buffer Version)
--------------------

.. rubric:: Syntax

.. code-block:: cpp

   namespace oneapi::mkl::blas::column_major {
       void dot(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_res,1> &result)
   }
.. code-block:: cpp

   namespace oneapi::mkl::blas::row_major {
       void dot(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_res,1> &result)
   }

.. container:: section

   .. rubric:: 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``. 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 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``.

.. container:: section

   .. rubric:: Output Parameters

   result
      Buffer where the result (a scalar) will be stored.


.. _onemkl_blas_dot_usm:

dot (USM Version)
-----------------

.. rubric:: Syntax

.. code-block:: cpp

   namespace oneapi::mkl::blas::column_major {
       sycl::event dot(sycl::queue &queue,
                       std::int64_t n,
                       const T *x,
                       std::int64_t incx,
                       const T *y,
                       std::int64_t incy,
                       T_res *result,
                       const std::vector<sycl::event> &dependencies = {})
   }
.. code-block:: cpp

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

.. container:: section

   .. rubric:: 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``. The array holding the 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 the input vector ``y``. The array holding the 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``.

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

.. container:: section

   .. rubric:: Output Parameters

   result
      Pointer to where the result (a scalar) will be stored.

.. container:: section

   .. rubric:: Return Values

   Output event to wait on to ensure computation is complete.


   **Parent topic:** :ref:`blas-level-1-routines`