statistics.py

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from biogeme import *


def nullLoglikelihood(availability,iterator):
    terms = {}
    for i,a in availability.items() :
        terms[i] = ( a!=0 )

    total = bioMultSum(terms)
    nl = -Sum(log(total),iterator)
    BIOGEME_OBJECT.STATISTICS['Null loglikelihood'] = nl
    return nl


def choiceStatistics(choiceSet,choice,iterator):
    n = {}
    for i in choiceSet:
        n[i] = Sum(choice == i,iterator)
    for i in choiceSet:
        s = 'Alt. %d chosen' % (i)
        BIOGEME_OBJECT.STATISTICS[s] = n[i]
    return n


def availabilityStatistics(availability,iterator):
    n = {}
    for i,a in availability.items():
        n[i] = Sum((a != 0),iterator)
    for i,a in availability.items():
        s = 'Alt. %d available' % (i)
        BIOGEME_OBJECT.STATISTICS[s] = n[i]
    return n    


def cteLoglikelihood(choiceSet,choice,iterator):
    n = choiceStatistics(choiceSet,choice,iterator)
    terms_l = {}
    terms_tot = {}
    for i in n:
        terms_l[i] = n[i] * log(n[i])
        terms_tot[i] = n[i]
    total = bioMultSum(terms_tot)
    l = bioMultSum(terms_l)
    l -= total * log(total)

    BIOGEME_OBJECT.STATISTICS['Cte loglikelihood (only for full choice sets)'] = l
    return l