Is it possible to create two models within one coding program for docplex.mp?

Question

Is it possible if we combine two models of docplex.mp within one pyton coding file? For example, mdl. and mdl2.

Thank you.

Answer 1

Yes. Suppose the 2 combined schools from https://github.com/AlexFleischerParis/zoodocplex/blob/master/zootwoinstancescombined.py

from docplex.mp.model import Model

#Two independent schools, first school 300 kids, second one 350
#Combined in a single model because of a coupling constraint
#(Total number of buses)

mdl = Model(name='buses')
nbbus40 = mdl.integer_var(name='nbBus40')
nbbus30 = mdl.integer_var(name='nbBus30')
nbbus40bis = mdl.integer_var(name='nbBus40bis')
nbbus30bis = mdl.integer_var(name='nbBus30bis')
mdl.add_constraint(nbbus40*40 + nbbus30*30 >= 300, 'kids')
mdl.add_constraint(nbbus40bis*40 + nbbus30bis*30 >= 350, 'kids2')
mdl.add_constraint(nbbus40+nbbus30+nbbus40bis+nbbus30bis<=17,'total nb of buses')
mdl.minimize(nbbus40*500 + nbbus30*400+nbbus40bis*500 + nbbus30bis*400)

mdl.solve(log_output=True,)

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

are not combined any more.

Then you can write

from docplex.mp.model import Model

#Two independent schools, first school 300 kids, second one 350


mdl1 = Model(name='buses1')
nbbus40 = mdl1.integer_var(name='nbBus40')
nbbus30 = mdl1.integer_var(name='nbBus30')

mdl2= Model(name='buses2')
nbbus40bis = mdl2.integer_var(name='nbBus40bis')
nbbus30bis = mdl2.integer_var(name='nbBus30bis')
mdl1.add_constraint(nbbus40*40 + nbbus30*30 >= 300, 'kids')
mdl2.add_constraint(nbbus40bis*40 + nbbus30bis*30 >= 350, 'kids2')

mdl1.minimize(nbbus40*500 + nbbus30*40)
mdl2.minimize(nbbus40bis*500 + nbbus30bis*400)

mdl1.solve(log_output=True,)
mdl2.solve(log_output=True,)

for v in mdl1.iter_integer_vars():
    print(v," = ",v.solution_value)

for v in mdl2.iter_integer_vars():
    print(v," = ",v.solution_value)