Decision Optimization

I need to add a constraint that decision variable with modulo expression.I noted that in Stackoverflow there is no direct method we cannot do it but we need to introduce a new decission variable.Is there any simple way that I can do this from docplex.

Stackoverflow link : https://stackoverflow.com/questions/55671058/understanding-mod-operator-in-math-vs-programming

I am looking some simple thing like below.

x = mymodel.integer_var();
r = mymodel.add_constraint(x % 12 == 0,'con2');

Is it possible to have like this. (IDE and languages  like minizinc have inbuilt it)

------------------------------
Suresh Abeyweera
------------------------------

#DecisionOptimization

You're not saying whethe ryou use Cplex (docplex.mp) or docplex.cp). I'll answer for docplex.mp, the idea is the same, syntax may differ.
If variable 'x' is 0 modulo 12, then it is necessarily an integer variable, which is a multiple of 12, so there must exist an integer variable `q` so that
x == 12* q,

x = mymodel.integer_var();
q = mymodel.integer_var() ; # the quotient var
r = mymodel.add_constraint(x == 12 * q)

asserting a reminder `r` would be as simple, stating that x == 12*q +r

    
    Philippe.

​​

------------------------------
Philippe Couronne
------------------------------

Original Message:
Sent: Thu October 08, 2020 01:53 AM
From: Suresh Abeyweera
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

I need to add a constraint that decision variable with modulo expression.I noted that in Stackoverflow there is no direct method we cannot do it but we need to introduce a new decission variable.Is there any simple way that I can do this from docplex.

Stackoverflow link : https://stackoverflow.com/questions/55671058/understanding-mod-operator-in-math-vs-programming

I am looking some simple thing like below.

x = mymodel.integer_var();
r = mymodel.add_constraint(x % 12 == 0,'con2');

Is it possible to have like this. (IDE and languages  like minizinc have inbuilt it)

------------------------------
Suresh Abeyweera
------------------------------

#DecisionOptimization

NB:

With docplex and cpoptimizer you can directly 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')

# and suppose we need to order quantities
# that should be 3 multipliers

mdl.add(nbbus40 % 3==0)
mdl.add(nbbus30 % 3==0)

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")


https://github.com/AlexFleischerParis/zoodocplex/blob/master/zoocpomodulo.py

------------------------------
ALEX FLEISCHER
------------------------------

Original Message:
Sent: Thu October 08, 2020 03:38 AM
From: Philippe Couronne
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

You're not saying whethe ryou use Cplex (docplex.mp) or docplex.cp). I'll answer for docplex.mp, the idea is the same, syntax may differ.
If variable 'x' is 0 modulo 12, then it is necessarily an integer variable, which is a multiple of 12, so there must exist an integer variable `q` so that
x == 12* q,

x = mymodel.integer_var();
q = mymodel.integer_var() ; # the quotient var
r = mymodel.add_constraint(x == 12 * q)

asserting a reminder `r` would be as simple, stating that x == 12*q +r

    
    Philippe.

​​

------------------------------
Philippe Couronne

Original Message:
Sent: Thu October 08, 2020 01:53 AM
From: Suresh Abeyweera
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

I need to add a constraint that decision variable with modulo expression.I noted that in Stackoverflow there is no direct method we cannot do it but we need to introduce a new decission variable.Is there any simple way that I can do this from docplex.

Stackoverflow link : https://stackoverflow.com/questions/55671058/understanding-mod-operator-in-math-vs-programming

I am looking some simple thing like below.

x = mymodel.integer_var();
r = mymodel.add_constraint(x % 12 == 0,'con2');

Is it possible to have like this. (IDE and languages  like minizinc have inbuilt it)

------------------------------
Suresh Abeyweera
------------------------------
#DecisionOptimization

Thanks Alex just noticed this approach is for the constraint programming. As far as it is constrained to the best approach to solve scheduling problems. Is there any method like this for mathematical programming.

------------------------------
Suresh Abeyweera
------------------------------

Original Message:
Sent: Thu October 08, 2020 04:55 AM
From: ALEX FLEISCHER
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

NB:

With docplex and cpoptimizer you can directly 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')

# and suppose we need to order quantities
# that should be 3 multipliers

mdl.add(nbbus40 % 3==0)
mdl.add(nbbus30 % 3==0)

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")


https://github.com/AlexFleischerParis/zoodocplex/blob/master/zoocpomodulo.py

------------------------------
ALEX FLEISCHER

Original Message:
Sent: Thu October 08, 2020 03:38 AM
From: Philippe Couronne
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

You're not saying whethe ryou use Cplex (docplex.mp) or docplex.cp). I'll answer for docplex.mp, the idea is the same, syntax may differ.
If variable 'x' is 0 modulo 12, then it is necessarily an integer variable, which is a multiple of 12, so there must exist an integer variable `q` so that
x == 12* q,

x = mymodel.integer_var();
q = mymodel.integer_var() ; # the quotient var
r = mymodel.add_constraint(x == 12 * q)

asserting a reminder `r` would be as simple, stating that x == 12*q +r

    
    Philippe.

​​

------------------------------
Philippe Couronne

Original Message:
Sent: Thu October 08, 2020 01:53 AM
From: Suresh Abeyweera
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

I need to add a constraint that decision variable with modulo expression.I noted that in Stackoverflow there is no direct method we cannot do it but we need to introduce a new decission variable.Is there any simple way that I can do this from docplex.

Stackoverflow link : https://stackoverflow.com/questions/55671058/understanding-mod-operator-in-math-vs-programming

I am looking some simple thing like below.

x = mymodel.integer_var();
r = mymodel.add_constraint(x % 12 == 0,'con2');

Is it possible to have like this. (IDE and languages  like minizinc have inbuilt it)

------------------------------
Suresh Abeyweera
------------------------------
#DecisionOptimization

Hi,

then you should follow Philippe 's advice and introduce a new decision variable

See https://github.com/AlexFleischerParis/zoodocplex/blob/master/zoomodulo.py

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*500 + nbbus30*400)

# and suppose we need to order quantities

# that should be 3 multipliers

nbbus40div3 = mdl.integer_var(name='nbBus40div3')

nbbus30div3 = mdl.integer_var(name='nbBus30div3')

mdl.add(nbbus40==3*nbbus40div3)

mdl.add(nbbus30==3*nbbus30div3)

mdl.solve()

mdl.export("c:\\temp\\buses.lp")

for v in mdl.iter_integer_vars():

print(v," = ",v.solution_value)

------------------------------
ALEX FLEISCHER
------------------------------

Original Message:
Sent: Thu October 08, 2020 11:18 PM
From: Suresh Abeyweera
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

Thanks Alex just noticed this approach is for the constraint programming. As far as it is constrained to the best approach to solve scheduling problems. Is there any method like this for mathematical programming.

------------------------------
Suresh Abeyweera

Original Message:
Sent: Thu October 08, 2020 04:55 AM
From: ALEX FLEISCHER
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

NB:

With docplex and cpoptimizer you can directly 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')

# and suppose we need to order quantities
# that should be 3 multipliers

mdl.add(nbbus40 % 3==0)
mdl.add(nbbus30 % 3==0)

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")


https://github.com/AlexFleischerParis/zoodocplex/blob/master/zoocpomodulo.py

------------------------------
ALEX FLEISCHER

Original Message:
Sent: Thu October 08, 2020 03:38 AM
From: Philippe Couronne
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

You're not saying whethe ryou use Cplex (docplex.mp) or docplex.cp). I'll answer for docplex.mp, the idea is the same, syntax may differ.
If variable 'x' is 0 modulo 12, then it is necessarily an integer variable, which is a multiple of 12, so there must exist an integer variable `q` so that
x == 12* q,

x = mymodel.integer_var();
q = mymodel.integer_var() ; # the quotient var
r = mymodel.add_constraint(x == 12 * q)

asserting a reminder `r` would be as simple, stating that x == 12*q +r

    
    Philippe.

​​

------------------------------
Philippe Couronne

Original Message:
Sent: Thu October 08, 2020 01:53 AM
From: Suresh Abeyweera
Subject: Can a modulo operation be expressed as a constraint in CPLEX?

I need to add a constraint that decision variable with modulo expression.I noted that in Stackoverflow there is no direct method we cannot do it but we need to introduce a new decission variable.Is there any simple way that I can do this from docplex.

Stackoverflow link : https://stackoverflow.com/questions/55671058/understanding-mod-operator-in-math-vs-programming

I am looking some simple thing like below.

x = mymodel.integer_var();
r = mymodel.add_constraint(x % 12 == 0,'con2');

Is it possible to have like this. (IDE and languages  like minizinc have inbuilt it)

------------------------------
Suresh Abeyweera
------------------------------
#DecisionOptimization