.. only:: html

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

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

    .. _sphx_glr_auto_numerical_methods_general_methods_plot_study_save_load.py:


Save/load a study
=================

The objective of this example is to demonstrate how to save the structures created within a script session to disk in order to be able to load them in a future session.

There are several possible ways to achieve this:

- with the standard pickle module
- with openturns's Study


.. code-block:: default

    from __future__ import print_function
    import openturns as ot
    import openturns.viewer as viewer
    from matplotlib import pylab as plt
    import os
    import pickle
    ot.Log.Show(ot.Log.NONE)








create objects to save


.. code-block:: default

    distribution = ot.Normal(4.0, 3.0)
    function = ot.SymbolicFunction(['x1', 'x2'], ['x1 + x2'])








**With the pickle module**

The objects are retrieved in the same order they are stored.

save objects


.. code-block:: default

    with open('study.pkl', 'wb') as f:
        pickle.dump(distribution, f)
        pickle.dump(function, f)








load saved objects


.. code-block:: default

    with open('study.pkl', 'rb') as f:
        loaded_distribution = pickle.load(f)
        loaded_function = pickle.load(f)
    str(loaded_distribution), str(loaded_function)





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

 Out:

 .. code-block:: none


    ('Normal(mu = 4, sigma = 3)', '[x1,x2]->[x1 + x2]')



**With OpenTURNS' Study**

In order to be able to manipulate the objects contained in a Study, it is necessary to:

- create the same empty structure in the new study,
- fill this new empty structure with the content of the loaded structure, identified with its name or its id.

Each object is identified whether with:

- its name: it is useful to give names to the objects we want to save. If no name has been given by the user, we can use the name by default. The name of each object saved can be checked in the file.XML created or by printing the study in the python interface (with the command print).
- its id number : this id number is unique for each object. It is useful to distinguish objects of same type which names are identical, equal to the default name given ('Unnamed'). This id number may be checked by printing the study loaded in the python interface (with the command print): be careful, this print operation must be performed after having loaded the study (the id number may be different from the one indicated in the file.XML associated to the study).

Create a Study Object


.. code-block:: default

    study = ot.Study()








Associate it to an XML file


.. code-block:: default

    fileName = 'study.xml'
    study.setStorageManager(ot.XMLStorageManager(fileName))








Add an object to the study; at this point it is not written to disk yet


.. code-block:: default

    study.add('distribution', distribution)
    study.add('function', function)








Save the study; this writes into the file


.. code-block:: default

    study.save()








Create a new study associated to the same file


.. code-block:: default

    study = ot.Study()
    study.setStorageManager(ot.XMLStorageManager(fileName))








Load the file and all its objects


.. code-block:: default

    study.load()








Check the content of the myStudy


.. code-block:: default

    print("Study = " , study)





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

 Out:

 .. code-block:: none

    Study =    196 => FunctionImplementation
    [x1,x2]->[x1 + x2]
      197 => Normal
    Normal(mu = 4, sigma = 3)
      'distribution' is aliased to 197
      'function' is aliased to 196




List names of stored objects


.. code-block:: default

    study.printLabels()





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

 Out:

 .. code-block:: none


    'distribution;function'



Check our 'distribution' labelled object was loaded


.. code-block:: default

    study.hasObject('distribution')





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

 Out:

 .. code-block:: none


    True



Load the objects; we must create a void object of the desired type (or parent type)


.. code-block:: default

    distributionLoaded = ot.Normal()
    functionLoaded = ot.Function()
    study.fillObject('distribution', loaded_distribution)
    study.fillObject('function', loaded_function)
    str(loaded_distribution), str(loaded_function)




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

 Out:

 .. code-block:: none


    ('Normal(mu = 4, sigma = 3)', '[x1,x2]->[x1 + x2]')




.. rst-class:: sphx-glr-timing

   **Total running time of the script:** ( 0 minutes  0.008 seconds)


.. _sphx_glr_download_auto_numerical_methods_general_methods_plot_study_save_load.py:


.. only :: html

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



  .. container:: sphx-glr-download sphx-glr-download-python

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



  .. container:: sphx-glr-download sphx-glr-download-jupyter

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


.. only:: html

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

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