Model specification

Script containing the model specification.

author:

Michel Bierlaire

date:

Wed Nov 1 17:37:33 2023

from biogeme.expressions import Beta, Variable, log
from biogeme.sampling_of_alternatives import CrossVariableTuple

Variable combining attributes of the alternatives and characteristics of the decision-maker

combined_variables = [
    CrossVariableTuple(
        'log_dist',
        log(
            (
                (Variable('user_lat') - Variable('rest_lat')) ** 2
                + (Variable('user_lon') - Variable('rest_lon')) ** 2
            )
            ** 0.5
        ),
    )
]

Parameters to estimate.

beta_rating = Beta('beta_rating', 0, None, None, 0)
beta_price = Beta('beta_price', 0, None, None, 0)
beta_chinese = Beta('beta_chinese', 0, None, None, 0)
beta_japanese = Beta('beta_japanese', 0, None, None, 0)
beta_korean = Beta('beta_korean', 0, None, None, 0)
beta_indian = Beta('beta_indian', 0, None, None, 0)
beta_french = Beta('beta_french', 0, None, None, 0)
beta_mexican = Beta('beta_mexican', 0, None, None, 0)
beta_lebanese = Beta('beta_lebanese', 0, None, None, 0)
beta_ethiopian = Beta('beta_ethiopian', 0, None, None, 0)
beta_log_dist = Beta('beta_log_dist', 0, None, None, 0)

Utility function.

V = (
    beta_rating * Variable('rating')
    + beta_price * Variable('price')
    + beta_chinese * Variable('category_Chinese')
    + beta_japanese * Variable('category_Japanese')
    + beta_korean * Variable('category_Korean')
    + beta_indian * Variable('category_Indian')
    + beta_french * Variable('category_French')
    + beta_mexican * Variable('category_Mexican')
    + beta_lebanese * Variable('category_Lebanese')
    + beta_ethiopian * Variable('category_Ethiopian')
    + beta_log_dist * Variable('log_dist')
)