.. note::
    :class: sphx-glr-download-link-note

    Click :ref:`here <sphx_glr_download_auto_examples_reuse_executor.py>` to download the full example code
.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_reuse_executor.py:


Reuse Executor
==============

This example highlights the ``loky`` API to reuse a ``ReusableProcessPool``.

The factory ``get_reusable_executor`` provides an executor. As long as this
executor is not in a broken state, it is reused for all the computation.




.. rst-class:: sphx-glr-script-out

 Out:

 .. code-block:: none

    All the jobs were run in a process different from main process
    All the computation where run in a single `ProcessPoolExecutor` with worker pid=463




|


.. code-block:: python

    import os
    import argparse
    from loky import get_reusable_executor


    def func_async(i):
        import os
        pid = os.getpid()
        return (2*i, pid)

    def test_1():
        executor = get_reusable_executor(max_workers=1)
        return executor.submit(func_async, 1)


    def test_2():
        executor = get_reusable_executor(max_workers=1)
        return executor.submit(func_async, 2)


    def test_3():
        executor = get_reusable_executor(max_workers=1)
        return executor.submit(func_async, 3)

    f1 = test_1()
    f2 = test_2()
    f3 = test_3()

    main_pid = os.getpid()
    results = [f1.result(), f2.result(), f3.result()]

    pids = [v[1] for v in results]

    for i, (val, pid) in enumerate(results):
        assert val == 2 * (i + 1)
        assert pid != main_pid
    print("All the jobs were run in a process different from main process")

    assert len(set(pids)) == 1
    print("All the computation where run in a single `ProcessPoolExecutor` with "
          "worker pid={}".format(pids[0]))

**Total running time of the script:** ( 0 minutes  0.155 seconds)


.. _sphx_glr_download_auto_examples_reuse_executor.py:


.. only :: html

 .. container:: sphx-glr-footer
    :class: sphx-glr-footer-example



  .. container:: sphx-glr-download

     :download:`Download Python source code: reuse_executor.py <reuse_executor.py>`



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: reuse_executor.ipynb <reuse_executor.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.readthedocs.io>`_