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Parallel Reduction for rvalues

third-party/tbb/doc/main/reference/rvalue_reduce.rst

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.. _rvalue_reduce:

Parallel Reduction for rvalues

.. contents:: :local: :depth: 1

Description


|full_name| implementation extends the ParallelReduceFunc <https://oneapi-spec.uxlfoundation.org/specifications/oneapi/latest/elements/onetbb/source/named_requirements/algorithms/par_reduce_func>_ and ParallelReduceReduction <https://oneapi-spec.uxlfoundation.org/specifications/oneapi/latest/elements/onetbb/source/named_requirements/algorithms/par_reduce_reduction>_ to optimize operating with rvalues using functional form of tbb::parallel_reduce and tbb::parallel_deterministic_reduce algorithms.

API


.. code:: cpp

#include <oneapi/tbb/parallel_reduce.h>

ParallelReduceFunc Requirements: Pseudo-Signature, Semantics

.. cpp:function:: Value Func::operator()(const Range& range, Value&& x) const

or

.. cpp:function:: Value Func::operator()(const Range& range, const Value& x) const

Accumulates the result for a subrange, starting with initial value ``x``. The ``Range`` type must meet the
`Range requirements <https://oneapi-spec.uxlfoundation.org/specifications/oneapi/latest/elements/onetbb/source/named_requirements/algorithms/range>`_.
The ``Value`` type must be the same as a corresponding template parameter for the `parallel_reduce algorithm <https://oneapi-spec.uxlfoundation.org/specifications/oneapi/latest/elements/onetbb/source/algorithms/functions/parallel_reduce_func>`_.

If both ``rvalue`` and ``lvalue`` forms are provided, the ``rvalue`` is preferred.

ParallelReduceReduction Requirements: Pseudo-Signature, Semantics

.. cpp:function:: Value Reduction::operator()(Value&& x, Value&& y) const

or

.. cpp:function:: Value Reduction::operator()(const Value& x, const Value& y) const

Combines the ``x`` and ``y`` results. The ``Value`` type must be the same as a corresponding template parameter for the `parallel_reduce algorithm <https://oneapi-spec.uxlfoundation.org/specifications/oneapi/latest/elements/onetbb/source/algorithms/functions/parallel_reduce_func>`_.

If both ``rvalue`` and ``lvalue`` forms are provided, the ``rvalue`` is preferred.

Example


.. literalinclude:: ./examples/rvalue_reduce.cpp :language: c++ :start-after: /begin_rvalue_reduce_example/ :end-before: /end_rvalue_reduce_example/

.. rubric:: See also

  • oneapi::tbb::parallel_reduce specification <https://oneapi-spec.uxlfoundation.org/specifications/oneapi/latest/elements/onetbb/source/algorithms/functions/parallel_reduce_func>_
  • oneapi::tbb::parallel_deterministic_reduce specification <https://oneapi-spec.uxlfoundation.org/specifications/oneapi/latest/elements/onetbb/source/algorithms/functions/parallel_deterministic_reduce_func>_
  • ParallelReduceFunc specification <https://oneapi-spec.uxlfoundation.org/specifications/oneapi/latest/elements/onetbb/source/named_requirements/algorithms/par_reduce_func>_
  • ParallelReduceReduction specification <https://oneapi-spec.uxlfoundation.org/specifications/oneapi/latest/elements/onetbb/source/named_requirements/algorithms/par_reduce_reduction>_