Hi,

let's go on with the example from https://www.linkedin.com/pulse/what-optimization-how-can-help-you-do-more-less-zoo-buses-fleischer/

Let's see how easy it is to use logical constraints in docplex

(Nearly as easy as in OPL https://www.ibm.com/developerworks/community/forums/html/topic?id=1e764610-ffd4-4e25-9a5f-4b380f05df64&ps=25 )

from docplex.mp.model import Model

mdl = Model(name='buses')
nbbus40 = mdl.integer_var(name='nbBus40')
nbbus30 = mdl.integer_var(name='nbBus30')
mdl.add_constraint(nbbus40*40 + nbbus30*30 >= 300, 'kids')
mdl.minimize(nbbus40*460 + nbbus30*360)

mdl.solve()

for v in mdl.iter_integer_vars():
    print(v," = ",v.solution_value)

print()
print("with the logical constraint")

nbKindOfBuses = mdl.integer_var(name='nbKindOfBuses')
mdl.add(nbKindOfBuses==(nbbus40>=1)+(nbbus30>=1))

mdl.minimize(nbbus40*460 + nbbus30*360+(nbKindOfBuses-1)*(500))

mdl.solve()

for v in mdl.iter_integer_vars():
    print(v," = ",v.solution_value)

gives

nbBus40  =  6.0
nbBus30  =  2.0

with the logical constraint
nbBus40  =  0
nbBus30  =  10.0
nbKindOfBuses  =  1.0

and

mdl.add(nbKindOfBuses==(nbbus40>=1)+(nbbus30>=1))

is a logical constraint (Not a zoological one!)

regards