Modified Utilities Function

[Natchaphon Leungbootnak]

Dear all,

I want to run logit model by using random regret minimization (RRM) instead of random utility maximization (RUM). I followed the python example of binary logit model (https://biogeme.epfl.ch/sphinx/auto_examples/tutorials/plot_b01_first_model.html). I modified RUM equations from:

car: asc_car + b_time * auto_time
transit: b_time * transit_time

to be RRM equations instead:

car: - math.log(1 + math.exp(0 - asc_car)) - math.log(1 + math.exp(b_time * (transit_time - auto_time)))

transit: - math.log(1 + math.exp(asc_car - 0)) - math.log(1 + math.exp(b_time * (auto_time - transit_time)))

However, it showed "TypeError: must be real number, not Minus". I tried to use sympy and numpy instead of math library to fix it, but it did not work.

Best regards,

Natchaphon

[Michel Bierlaire]

You should not use the mathematical expressions from the `math` package, but from the biogeme.expressions package.

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Michel Bierlaire
Transport and Mobility Laboratory
School of Architecture, Civil and Environmental Engineering
EPFL - Ecole Polytechnique Fédérale de Lausanne
http://transp-or.epfl.ch
http://people.epfl.ch/michel.bierlaire