.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "auto_examples/bayesian_swissmetro/plot_b09_nested.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_bayesian_swissmetro_plot_b09_nested.py: 9. Nested logit model ===================== Bayesian estimation of a nested logit model. Michel Bierlaire, EPFL Mon Nov 03 2025, 20:02:56 .. GENERATED FROM PYTHON SOURCE LINES 11-21 .. code-block:: Python from IPython.core.display_functions import display from biogeme import biogeme_logging as blog from biogeme.bayesian_estimation import BayesianResults, get_pandas_estimated_parameters from biogeme.biogeme import BIOGEME from biogeme.expressions import Beta from biogeme.models import lognested from biogeme.nests import NestsForNestedLogit, OneNestForNestedLogit .. GENERATED FROM PYTHON SOURCE LINES 22-23 See the data processing script: :ref:`swissmetro_data`. .. GENERATED FROM PYTHON SOURCE LINES 23-40 .. code-block:: Python from swissmetro_data import ( CAR_AV_SP, CAR_CO_SCALED, CAR_TT_SCALED, CHOICE, SM_AV, SM_COST_SCALED, SM_TT_SCALED, TRAIN_AV_SP, TRAIN_COST_SCALED, TRAIN_TT_SCALED, database, ) logger = blog.get_screen_logger(level=blog.INFO) logger.info('Example b09_nested') .. rst-class:: sphx-glr-script-out .. code-block:: none Example b09_nested .. GENERATED FROM PYTHON SOURCE LINES 41-42 Parameters to be estimated. .. GENERATED FROM PYTHON SOURCE LINES 42-49 .. code-block:: Python 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_time = Beta('b_time', 0, None, 0, 0) b_cost = Beta('b_cost', 0, None, 0, 0) nest_parameter = Beta('nest_parameter', 1, 1, 3, 0) .. GENERATED FROM PYTHON SOURCE LINES 50-51 Definition of the utility functions. .. GENERATED FROM PYTHON SOURCE LINES 51-55 .. code-block:: Python v_train = asc_train + b_time * TRAIN_TT_SCALED + b_cost * TRAIN_COST_SCALED v_swissmetro = asc_sm + b_time * SM_TT_SCALED + b_cost * SM_COST_SCALED v_car = asc_car + b_time * CAR_TT_SCALED + b_cost * CAR_CO_SCALED .. GENERATED FROM PYTHON SOURCE LINES 56-57 Associate utility functions with the numbering of alternatives. .. GENERATED FROM PYTHON SOURCE LINES 57-59 .. code-block:: Python v = {1: v_train, 2: v_swissmetro, 3: v_car} .. GENERATED FROM PYTHON SOURCE LINES 60-61 Associate the availability conditions with the alternatives. .. GENERATED FROM PYTHON SOURCE LINES 61-63 .. code-block:: Python av = {1: TRAIN_AV_SP, 2: SM_AV, 3: CAR_AV_SP} .. GENERATED FROM PYTHON SOURCE LINES 64-68 Definition of nests. Only the non-trivial nests must be defined. A trivial nest is a nest containing exactly one alternative. In this example, we create a nest for the existing modes, that is train (1) and car (3). .. GENERATED FROM PYTHON SOURCE LINES 68-75 .. code-block:: Python existing = OneNestForNestedLogit( nest_param=nest_parameter, list_of_alternatives=[1, 3], name='existing' ) nests = NestsForNestedLogit(choice_set=list(v), tuple_of_nests=(existing,)) .. rst-class:: sphx-glr-script-out .. code-block:: none The following elements do not appear in any nest and are assumed each to be alone in a separate nest: {2}. If it is not the intention, check the assignment of alternatives to nests. .. GENERATED FROM PYTHON SOURCE LINES 76-79 Definition of the model. This is the contribution of each observation to the log likelihood function. The choice model is a nested logit, with availability conditions. .. GENERATED FROM PYTHON SOURCE LINES 79-81 .. code-block:: Python log_probability = lognested(v, av, nests, CHOICE) .. GENERATED FROM PYTHON SOURCE LINES 82-83 Create the Biogeme object. .. GENERATED FROM PYTHON SOURCE LINES 83-89 .. code-block:: Python the_biogeme = BIOGEME( database, log_probability, ) the_biogeme.model_name = 'b09_nested' .. rst-class:: sphx-glr-script-out .. code-block:: none Biogeme parameters read from biogeme.toml. .. GENERATED FROM PYTHON SOURCE LINES 90-91 Estimate the parameters. .. GENERATED FROM PYTHON SOURCE LINES 91-98 .. code-block:: Python try: results = BayesianResults.from_netcdf( filename=f'saved_results/{the_biogeme.model_name}.nc' ) except FileNotFoundError: results = the_biogeme.bayesian_estimation() .. rst-class:: sphx-glr-script-out .. code-block:: none *** Initial values of the parameters are obtained from the file __b09_nested.iter Cannot read file __b09_nested.iter. Statement is ignored. Starting values for the algorithm: {} /Users/bierlair/MyFiles/github/biogeme/src/biogeme/biogeme.py:832: UserWarning: Note: JAX currently sees 1 CPU device. To parallelize across CPU devices, set XLA_FLAGS as above and restart Python/Jupyter. macOS / Linux (bash/zsh): export XLA_FLAGS="--xla_force_host_platform_device_count=" Jupyter (new cell, before `import jax`): %env XLA_FLAGS="--xla_force_host_platform_device_count=" warning_cpu_devices() Detected CPU devices: 1 | System logical cores: 12 Current XLA_FLAGS: --xla_force_host_platform_device_count=100 Platform: Darwin 24.6.0 | Python: 3.13.1 Auto sampling: JAX available (devices=1, platforms=cpu) → numpyro/vectorized /Users/bierlair/MyFiles/github/biogeme/src/biogeme/biogeme.py:859: UserWarning: The effect of Potentials on other parameters is ignored during prior predictive sampling. This is likely to lead to invalid or biased predictive samples. pm.sample_prior_predictive( 0%| | 0/4000 [00:00` .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: plot_b09_nested.py ` .. container:: sphx-glr-download sphx-glr-download-zip :download:`Download zipped: plot_b09_nested.zip ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_