biogeme.latent_variables.measurement_equations module

JAX-compatible ordered-probit measurement equations for Biogeme latent-variable models.

This module constructs the joint ordered-probit measurement model typically used in hybrid choice models. It combines:

  • latent-variable definitions (structural equations, normalization rules),

  • ordinal indicators (intercepts, latent-variable loadings, measurement scales),

  • Likert-scale definitions (categories and ordered thresholds),

  • consistency checks across model components,

  • JAX-friendly Biogeme Expression objects.

Thresholds (cut-points) are obtained from the LikertType associated with each indicator via get_thresholds(). Threshold sharing relies on parameter naming: if multiple indicators (or types) produce cut-points with identical parameter names, Biogeme will estimate a single shared set of parameters.

The main entry points are:

Michel Bierlaire Thu Dec 11 2025, 16:26:07

biogeme.latent_variables.measurement_equations.log_measurement_equations_jax(latent_variables, likert_indicators, likert_types, draw_type)[source]

Return the sum of log ordered-probit measurement likelihood terms.

Parameters:

  • latent_variables (list[LatentVariable]) – Latent-variable objects defining structural equations and associated indicators.

  • likert_indicators (list[LikertIndicator]) – Likert indicator objects providing measurement parameters.

  • likert_types (list[LikertType]) – Likert-type objects defining categories and thresholds.

  • draw_type (str) – Draw type assigned to latent variables for JAX.

Return type:

Expression

Returns:

Expression representing the sum of log ordered-probit likelihood terms.

biogeme.latent_variables.measurement_equations.measurement_equations_jax(latent_variables, likert_indicators, likert_types, draw_type)[source]

Return the product of ordered-probit measurement likelihood terms.

Parameters:

  • latent_variables (list[LatentVariable]) – Latent-variable objects defining structural equations and associated indicators.

  • likert_indicators (list[LikertIndicator]) – Likert indicator objects providing measurement parameters.

  • likert_types (list[LikertType]) – Likert-type objects defining categories and thresholds.

  • draw_type (str) – Draw type assigned to latent variables for JAX.

Return type:

Expression

Returns:

Expression representing the product of ordered-probit likelihood terms.