Hi,

I wrote https://www.ibm.com/developerworks/community/forums/html/topic?id=a8580237-639a-411b-b1df-f390a24da06c&ps=25

for CPLEX MIP

Let s have a look at CPO now.

In docplex CPO we can write

from docplex.cp.model import CpoModel

mdl = CpoModel(name='buses')
nbbus40 = mdl.integer_var(0,1000,name='nbBus40')
nbbus30 = mdl.integer_var(0,1000,name='nbBus30')
mdl.add(nbbus40*40 + nbbus30*30 >= 300)
mdl.minimize(nbbus40*500 + nbbus30*400)

msol=mdl.solve()

print(msol[nbbus40]," buses 40 seats")
print(msol[nbbus30]," buses 30 seats")

and then if we want to read data from a list of tuple

We may rely on:

• a dictionnary integer_var_dict

from docplex.cp.model import CpoModel

# Data

Buses=[
    (40,500),
    (30,400)
    ]

nbKids=300

# Indexes

busSize=0;
busCost=1;

for b in Buses:
    print("buses with ",b[busSize]," seats cost ",b[busCost])

mdl = CpoModel(name='buses')

#decision variables
mdl.nbBus=mdl.integer_var_dict(Buses,0,1000,name="nbBus")

# Constraint
mdl.add(sum(mdl.nbBus[b]*b[busSize] for b in Buses) >= nbKids)

# Objective
mdl.minimize(sum(mdl.nbBus[b]*b[busCost] for b in Buses))

msol=mdl.solve()

# Dislay solution
for b in Buses:
    print(msol[mdl.nbBus[b]]," buses with ",b[busSize]," seats");

• variables integer_var

from docplex.cp.model import CpoModel

# Data

Buses=[
    (40,500),
    (30,400)
    ]

nbKids=300

# Indexes

busSize=0;
busCost=1;

for b in Buses:
    print("buses with ",b[busSize]," seats cost ",b[busCost])

mdl = CpoModel(name='buses')

#decision variables
mdl.nbBus = {b: mdl.integer_var(0,1000,name="nbBus"+str(b[busSize])) for b in Buses}

# Constraint
mdl.add(sum(mdl.nbBus[b]*b[busSize] for b in Buses) >= nbKids)

# Objective
mdl.minimize(sum(mdl.nbBus[b]*b[busCost] for b in Buses))

msol=mdl.solve()

# Dislay solution
for b in Buses:
    print(msol[mdl.nbBus[b]]," buses with ",b[busSize]," seats");

 

 

• list integer_var_list

from docplex.cp.model import CpoModel

# Data

Buses=[
    (40,500),
    (30,400)
    ]

nbKids=300
nbSizes=len(Buses)

# Indexes

busSize=0;
busCost=1;

for b in Buses:
    print("buses with ",b[busSize]," seats cost ",b[busCost])

mdl = CpoModel(name='buses')

#decision variables

mdl.nbBus = mdl.integer_var_list(nbSizes,0,1000,name="nbBus")

# Constraint
mdl.add(sum(mdl.nbBus[b]*Buses[b][busSize] for b in range(0,nbSizes)) >= nbKids)

# Objective
mdl.minimize(sum(mdl.nbBus[b]*Buses[b][busCost] for b in range(0,nbSizes)))

msol=mdl.solve()

# Dislay solution
for b  in range(0,nbSizes):
    print(msol[mdl.nbBus[b]]," buses with ",Buses[b][busSize]," seats");

   

 

regards