.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_examples/swissmetro/plot_b06unif_mixture_integral.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

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

        :ref:`Go to the end <sphx_glr_download_auto_examples_swissmetro_plot_b06unif_mixture_integral.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_swissmetro_plot_b06unif_mixture_integral.py:


Mixture of logit models
=======================

Example of a mixture of logit models, using numerical integration.
The mixing distribution is uniform.

:author: Michel Bierlaire, EPFL
:date: Sun Apr  9 17:52:52 2023

.. GENERATED FROM PYTHON SOURCE LINES 13-25

.. code-block:: default


    import biogeme.biogeme_logging as blog
    import biogeme.biogeme as bio
    from biogeme import models
    from biogeme.expressions import (
        Beta,
        Integrate,
        RandomVariable,
        exp,
        log,
    )








.. GENERATED FROM PYTHON SOURCE LINES 26-27

See the data processing script: :ref:`swissmetro_data`.

.. GENERATED FROM PYTHON SOURCE LINES 27-44

.. code-block:: default

    from swissmetro_data import (
        database,
        CHOICE,
        SM_AV,
        CAR_AV_SP,
        TRAIN_AV_SP,
        TRAIN_TT_SCALED,
        TRAIN_COST_SCALED,
        SM_TT_SCALED,
        SM_COST_SCALED,
        CAR_TT_SCALED,
        CAR_CO_SCALED,
    )

    logger = blog.get_screen_logger(level=blog.INFO)
    logger.info('Example b06unif_mixture_integral.py')





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

 .. code-block:: none

    Example b06unif_mixture_integral.py 




.. GENERATED FROM PYTHON SOURCE LINES 45-46

Parameters to be estimated.

.. GENERATED FROM PYTHON SOURCE LINES 46-51

.. code-block:: default

    ASC_CAR = Beta('ASC_CAR', 0, None, None, 0)
    ASC_TRAIN = Beta('ASC_TRAIN', 0, None, None, 0)
    ASC_SM = Beta('ASC_SM', 0, None, None, 1)
    B_COST = Beta('B_COST', 0, None, None, 0)








.. GENERATED FROM PYTHON SOURCE LINES 52-54

Define a random parameter, normally distributed, designed to be used
for numerical integration

.. GENERATED FROM PYTHON SOURCE LINES 54-58

.. code-block:: default

    B_TIME = Beta('B_TIME', 0, None, None, 0)
    B_TIME_S = Beta('B_TIME_S', 1, None, None, 0)
    omega = RandomVariable('omega')








.. GENERATED FROM PYTHON SOURCE LINES 59-65

.. |infinity| unicode:: U+221E
   :trim:

As the numerical integration ranges from -|infinity| \  to + |infinity| ,
we need to perform a change of variable in order to integrate
between -1 and 1.

.. GENERATED FROM PYTHON SOURCE LINES 65-71

.. code-block:: default

    LOWER_BND = -1
    UPPER_BND = 1
    x = LOWER_BND + (UPPER_BND - LOWER_BND) / (1 + exp(-omega))
    dx = (UPPER_BND - LOWER_BND) * exp(-omega) * (1 + exp(-omega)) ** (-2)
    B_TIME_RND = B_TIME + B_TIME_S * x








.. GENERATED FROM PYTHON SOURCE LINES 72-73

Definition of the utility functions.

.. GENERATED FROM PYTHON SOURCE LINES 73-77

.. code-block:: default

    V1 = ASC_TRAIN + B_TIME_RND * TRAIN_TT_SCALED + B_COST * TRAIN_COST_SCALED
    V2 = ASC_SM + B_TIME_RND * SM_TT_SCALED + B_COST * SM_COST_SCALED
    V3 = ASC_CAR + B_TIME_RND * CAR_TT_SCALED + B_COST * CAR_CO_SCALED








.. GENERATED FROM PYTHON SOURCE LINES 78-79

Associate utility functions with the numbering of alternatives.

.. GENERATED FROM PYTHON SOURCE LINES 79-81

.. code-block:: default

    V = {1: V1, 2: V2, 3: V3}








.. GENERATED FROM PYTHON SOURCE LINES 82-83

Associate the availability conditions with the alternatives.

.. GENERATED FROM PYTHON SOURCE LINES 83-85

.. code-block:: default

    av = {1: TRAIN_AV_SP, 2: SM_AV, 3: CAR_AV_SP}








.. GENERATED FROM PYTHON SOURCE LINES 86-87

Conditional on omega, we have a logit model (called the kernel).

.. GENERATED FROM PYTHON SOURCE LINES 87-89

.. code-block:: default

    condprob = models.logit(V, av, CHOICE)








.. GENERATED FROM PYTHON SOURCE LINES 90-91

We integrate over omega using numerical integration.

.. GENERATED FROM PYTHON SOURCE LINES 91-93

.. code-block:: default

    logprob = log(Integrate(condprob * dx / (UPPER_BND - LOWER_BND), 'omega'))








.. GENERATED FROM PYTHON SOURCE LINES 94-95

Create the Biogeme object.

.. GENERATED FROM PYTHON SOURCE LINES 95-98

.. code-block:: default

    the_biogeme = bio.BIOGEME(database, logprob)
    the_biogeme.modelName = '06unif_mixture_integral'





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

 .. code-block:: none

    File biogeme.toml has been parsed. 




.. GENERATED FROM PYTHON SOURCE LINES 99-100

Estimate the parameters

.. GENERATED FROM PYTHON SOURCE LINES 100-102

.. code-block:: default

    results = the_biogeme.estimate()





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

 .. code-block:: none

    *** Initial values of the parameters are obtained from the file __06unif_mixture_integral.iter 
    Cannot read file __06unif_mixture_integral.iter. Statement is ignored. 
    Optimization algorithm: hybrid Newton/BFGS with simple bounds [simple_bounds] 
    ** Optimization: Newton with trust region for simple bounds 
    Iter.         ASC_CAR       ASC_TRAIN          B_COST          B_TIME        B_TIME_S     Function    Relgrad   Radius      Rho      
        0           -0.18           -0.69           -0.37              -1            0.87      5.4e+03      0.045       10        1   ++ 
        1          0.0036           -0.56           -0.99            -1.6             1.9      5.2e+03      0.021    1e+02      1.1   ++ 
        2           0.095           -0.44            -1.2            -2.1             2.5      5.2e+03     0.0067    1e+03      1.2   ++ 
        3            0.14           -0.39            -1.3            -2.3             2.8      5.2e+03      0.001    1e+04      1.1   ++ 
        4            0.14           -0.39            -1.3            -2.3             2.9      5.2e+03    2.8e-05    1e+05        1   ++ 
        5            0.14           -0.39            -1.3            -2.3             2.9      5.2e+03    2.2e-08    1e+05        1   ++ 
    Results saved in file 06unif_mixture_integral.html 
    Results saved in file 06unif_mixture_integral.pickle 




.. GENERATED FROM PYTHON SOURCE LINES 103-105

.. code-block:: default

    print(results.short_summary())





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

 .. code-block:: none

    Results for model 06unif_mixture_integral
    Nbr of parameters:              5
    Sample size:                    6768
    Excluded data:                  3960
    Final log likelihood:           -5215.072
    Akaike Information Criterion:   10440.14
    Bayesian Information Criterion: 10474.24





.. GENERATED FROM PYTHON SOURCE LINES 106-108

.. code-block:: default

    pandas_results = results.getEstimatedParameters()
    pandas_results





.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">
    <div>
    <style scoped>
        .dataframe tbody tr th:only-of-type {
            vertical-align: middle;
        }

        .dataframe tbody tr th {
            vertical-align: top;
        }

        .dataframe thead th {
            text-align: right;
        }
    </style>
    <table border="1" class="dataframe">
      <thead>
        <tr style="text-align: right;">
          <th></th>
          <th>Value</th>
          <th>Rob. Std err</th>
          <th>Rob. t-test</th>
          <th>Rob. p-value</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <th>ASC_CAR</th>
          <td>0.144949</td>
          <td>0.053305</td>
          <td>2.719231</td>
          <td>6.543384e-03</td>
        </tr>
        <tr>
          <th>ASC_TRAIN</th>
          <td>-0.385033</td>
          <td>0.066018</td>
          <td>-5.832246</td>
          <td>5.468613e-09</td>
        </tr>
        <tr>
          <th>B_COST</th>
          <td>-1.277902</td>
          <td>0.086617</td>
          <td>-14.753425</td>
          <td>0.000000e+00</td>
        </tr>
        <tr>
          <th>B_TIME</th>
          <td>-2.320416</td>
          <td>0.126068</td>
          <td>-18.405991</td>
          <td>0.000000e+00</td>
        </tr>
        <tr>
          <th>B_TIME_S</th>
          <td>2.875314</td>
          <td>0.199949</td>
          <td>14.380228</td>
          <td>0.000000e+00</td>
        </tr>
      </tbody>
    </table>
    </div>
    </div>
    <br />
    <br />


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

   **Total running time of the script:** (0 minutes 11.420 seconds)


.. _sphx_glr_download_auto_examples_swissmetro_plot_b06unif_mixture_integral.py:

.. only:: html

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




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

      :download:`Download Python source code: plot_b06unif_mixture_integral.py <plot_b06unif_mixture_integral.py>`

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

      :download:`Download Jupyter notebook: plot_b06unif_mixture_integral.ipynb <plot_b06unif_mixture_integral.ipynb>`


.. only:: html

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

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