.. only:: html

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

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

    .. _sphx_glr_auto_examples_plot_backend.py:


.. _l-example-backend-api:

ONNX Runtime Backend for ONNX
=============================

*ONNX Runtime* extends the 
`onnx backend API <https://github.com/onnx/onnx/blob/master/docs/ImplementingAnOnnxBackend.md>`_
to run predictions using this runtime.
Let's use the API to compute the prediction
of a simple logistic regression model.


.. code-block:: default

    import numpy as np
    from onnxruntime import datasets
    from onnxruntime.capi.onnxruntime_pybind11_state import InvalidArgument
    import onnxruntime.backend as backend
    from onnx import load

    name = datasets.get_example("logreg_iris.onnx")
    model = load(name)

    rep = backend.prepare(model, 'CPU')
    x = np.array([[-1.0, -2.0]], dtype=np.float32)
    try:
        label, proba = rep.run(x)
        print("label={}".format(label))
        print("probabilities={}".format(proba))
    except (RuntimeError, InvalidArgument) as e:
        print(e)





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

 Out:

 .. code-block:: none

    [ONNXRuntimeError] : 2 : INVALID_ARGUMENT : Got invalid dimensions for input: float_input for the following indices
     index: 0 Got: 1 Expected: 3
     Please fix either the inputs or the model.




The device depends on how the package was compiled,
GPU or CPU.


.. code-block:: default

    from onnxruntime import get_device
    print(get_device())





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

 Out:

 .. code-block:: none

    CPU




The backend can also directly load the model
without using *onnx*.


.. code-block:: default


    rep = backend.prepare(name, 'CPU')
    x = np.array([[-1.0, -2.0]], dtype=np.float32)
    try:
        label, proba = rep.run(x)
        print("label={}".format(label))
        print("probabilities={}".format(proba))
    except (RuntimeError, InvalidArgument) as e:
        print(e)





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

 Out:

 .. code-block:: none

    [ONNXRuntimeError] : 2 : INVALID_ARGUMENT : Got invalid dimensions for input: float_input for the following indices
     index: 0 Got: 1 Expected: 3
     Please fix either the inputs or the model.




The backend API is implemented by other frameworks
and makes it easier to switch between multiple runtimes
with the same API.


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

   **Total running time of the script:** ( 0 minutes  0.047 seconds)


.. _sphx_glr_download_auto_examples_plot_backend.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_backend.py <plot_backend.py>`



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

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


.. only:: html

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

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