.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "auto_examples/swissmetro/plot_b25triangular_mixture.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note :ref:`Go to the end ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_auto_examples_swissmetro_plot_b25triangular_mixture.py: Triangular mixture of logit =========================== Example of a mixture of logit models, using Monte-Carlo integration. The mixing distribution is specified by the user. Here, a triangular distribution. :author: Michel Bierlaire, EPFL :date: Wed Apr 12 18:24:18 2023 .. GENERATED FROM PYTHON SOURCE LINES 15-22 .. code-block:: default import numpy as np import biogeme.biogeme_logging as blog import biogeme.biogeme as bio from biogeme import models from biogeme.expressions import Beta, bioDraws, log, MonteCarlo .. GENERATED FROM PYTHON SOURCE LINES 23-24 See the data processing script: :ref:`swissmetro_data`. .. GENERATED FROM PYTHON SOURCE LINES 24-41 .. code-block:: default from swissmetro_data import ( database, CHOICE, CAR_AV_SP, TRAIN_AV_SP, TRAIN_TT_SCALED, TRAIN_COST_SCALED, SM_TT_SCALED, SM_COST_SCALED, CAR_TT_SCALED, CAR_CO_SCALED, SM_AV, ) logger = blog.get_screen_logger(level=blog.INFO) logger.info('Example b25triangular_mixture.py') .. rst-class:: sphx-glr-script-out .. code-block:: none Example b25triangular_mixture.py .. GENERATED FROM PYTHON SOURCE LINES 42-43 Parameters to be estimated. .. GENERATED FROM PYTHON SOURCE LINES 43-48 .. 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 49-53 Define a random parameter with a triangular distribution, designed to be used for Monte-Carlo simulation. The triangular distribution is not directly available from Biogeme. The draws have to be generated by a function provided by the user. .. GENERATED FROM PYTHON SOURCE LINES 55-56 Mean of the distribution. .. GENERATED FROM PYTHON SOURCE LINES 56-58 .. code-block:: default B_TIME = Beta('B_TIME', 0, None, None, 0) .. GENERATED FROM PYTHON SOURCE LINES 59-61 Scale of the distribution. It is advised not to use 0 as starting value for the following parameter. .. GENERATED FROM PYTHON SOURCE LINES 61-64 .. code-block:: default B_TIME_S = Beta('B_TIME_S', 1, None, None, 0) .. GENERATED FROM PYTHON SOURCE LINES 65-66 Function generating the draws. .. GENERATED FROM PYTHON SOURCE LINES 66-74 .. code-block:: default def the_triangular_generator(sample_size: int, number_of_draws: int) -> np.ndarray: """ User-defined random number generator to the database. See the numpy.random documentation to obtain a list of other distributions. """ return np.random.triangular(-1, 0, 1, (sample_size, number_of_draws)) .. GENERATED FROM PYTHON SOURCE LINES 75-76 Associate the function with a name. .. GENERATED FROM PYTHON SOURCE LINES 76-83 .. code-block:: default myRandomNumberGenerators = { 'TRIANGULAR': ( the_triangular_generator, 'Draws from a triangular distribution', ) } .. GENERATED FROM PYTHON SOURCE LINES 84-85 Submit the generator to the database. .. GENERATED FROM PYTHON SOURCE LINES 85-87 .. code-block:: default database.setRandomNumberGenerators(myRandomNumberGenerators) .. GENERATED FROM PYTHON SOURCE LINES 88-90 Define a random parameter with a triangular distribution, designed to be used for Monte-Carlo simulation. .. GENERATED FROM PYTHON SOURCE LINES 90-92 .. code-block:: default B_TIME_RND = B_TIME + B_TIME_S * bioDraws('B_TIME_RND', 'TRIANGULAR') .. GENERATED FROM PYTHON SOURCE LINES 93-94 Definition of the utility functions. .. GENERATED FROM PYTHON SOURCE LINES 94-98 .. 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 99-100 Associate utility functions with the numbering of alternatives .. GENERATED FROM PYTHON SOURCE LINES 100-102 .. code-block:: default V = {1: V1, 2: V2, 3: V3} .. GENERATED FROM PYTHON SOURCE LINES 103-104 Associate the availability conditions with the alternatives .. GENERATED FROM PYTHON SOURCE LINES 104-106 .. code-block:: default av = {1: TRAIN_AV_SP, 2: SM_AV, 3: CAR_AV_SP} .. GENERATED FROM PYTHON SOURCE LINES 107-108 Conditional to B_TIME_RND, we have a logit model (called the kernel) .. GENERATED FROM PYTHON SOURCE LINES 108-110 .. code-block:: default prob = models.logit(V, av, CHOICE) .. GENERATED FROM PYTHON SOURCE LINES 111-112 We integrate over B_TIME_RND using Monte-Carlo .. GENERATED FROM PYTHON SOURCE LINES 112-114 .. code-block:: default logprob = log(MonteCarlo(prob)) .. GENERATED FROM PYTHON SOURCE LINES 115-119 Create the Biogeme object. As the objective is to illustrate the syntax, we calculate the Monte-Carlo approximation with a small number of draws. To achieve that, we provide a parameter file different from the default one. .. GENERATED FROM PYTHON SOURCE LINES 119-122 .. code-block:: default the_biogeme = bio.BIOGEME(database, logprob, parameter_file='few_draws.toml') the_biogeme.modelName = 'b25triangular_mixture' .. rst-class:: sphx-glr-script-out .. code-block:: none File few_draws.toml has been parsed. .. GENERATED FROM PYTHON SOURCE LINES 123-124 Estimate the parameters .. GENERATED FROM PYTHON SOURCE LINES 124-126 .. 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 __b25triangular_mixture.iter Cannot read file __b25triangular_mixture.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 -0.24 -0.64 -0.43 -1 0.9 5.4e+03 0.042 10 1 ++ 1 0.033 -0.5 -1 -1.7 3.1 5.2e+03 0.029 1e+02 1 ++ 2 0.095 -0.43 -1.2 -2.1 3.5 5.2e+03 0.0039 1e+03 1.1 ++ 3 0.13 -0.4 -1.3 -2.2 3.8 5.2e+03 0.00049 1e+04 1.1 ++ 4 0.13 -0.4 -1.3 -2.2 3.9 5.2e+03 6.4e-06 1e+05 1 ++ 5 0.13 -0.4 -1.3 -2.2 3.9 5.2e+03 1.1e-09 1e+05 1 ++ Results saved in file b25triangular_mixture.html Results saved in file b25triangular_mixture.pickle .. GENERATED FROM PYTHON SOURCE LINES 127-129 .. code-block:: default print(results.short_summary()) .. rst-class:: sphx-glr-script-out .. code-block:: none Results for model b25triangular_mixture Nbr of parameters: 5 Sample size: 6768 Excluded data: 3960 Final log likelihood: -5215.848 Akaike Information Criterion: 10441.7 Bayesian Information Criterion: 10475.8 .. GENERATED FROM PYTHON SOURCE LINES 130-132 .. code-block:: default pandas_results = results.getEstimatedParameters() pandas_results .. raw:: html
Value Rob. Std err Rob. t-test Rob. p-value
ASC_CAR 0.131377 0.052072 2.522989 1.163620e-02
ASC_TRAIN -0.400569 0.065834 -6.084497 1.168578e-09
B_COST -1.277153 0.085682 -14.905718 0.000000e+00
B_TIME -2.244201 0.117954 -19.026152 0.000000e+00
B_TIME_S 3.893612 0.292471 13.312801 0.000000e+00


.. rst-class:: sphx-glr-timing **Total running time of the script:** (0 minutes 8.600 seconds) .. _sphx_glr_download_auto_examples_swissmetro_plot_b25triangular_mixture.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_b25triangular_mixture.py ` .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: plot_b25triangular_mixture.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_