docplex (a.k.a. IBM® Decision Optimization CPLEX® Modeling for Python) is a Python modeling API that provides modules for mathematical programming via CPLEX and constraint programming via CP Optimizer.
Questions tagged [docplex]
316 questions
0
votes
1 answer
DOCPLEX does not work - CPLEX runtime not found
I am facing an error like below, while I have installed docplex module and am using python 3.7/3.8. Would you please help me?
Traceback (most recent call last):
File "C:/Users/xxx/PycharmProjects/pythonProject/EPC _LTC.py", line 155, in
…
mdslt
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0
votes
4 answers
Python 3.7 cannot use DOCPLEX
I have coded a mathematical model and want to solve it using DOCPLEX module. My interpreter is Python 3.7. However, after doing a lot of effort, I will face the following error:
Traceback (most recent call last):
File…
mdslt
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- 1
- 10
0
votes
1 answer
Cplex for Linear Program: Are DOCplex decision variables assumed to be non-negative?
I want to write a simple LP using docplex. Suppose I have three variables: x, y, and z, the constraint is 4x + 9y - 18.7 <= z. I wrote the constraint with the code model.add_constraint(4 * x + 9 * y - 18.7 <= z). Then I set minimize z as my…
Francis
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1 answer
Printing all constraints using DOcplex
I am actually running a MILP on Python using DOcplex and it is my very first time using it. It is saying that my model which I ran on Lindo is infeasible. Therefore, I am guessing that I erroneously entered my constraints, but I cannot view them. I…
Bree
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1 answer
How to express a quadratic objective in Docplex on python
If any one could help ,I can't express the objective function, this is my code:
import numpy as np
def portfolio_return( weights, returns):
return weights.T @ returns
def portfolio_vol( weights, covmatrix):
return np.sqrt(weights.T @…
Yassine
- 11
- 2
0
votes
2 answers
Constraints in DocCplex on Python don't work
I'm trying to solve an optimization problem, but when I insert this constraint it doesn't work:
'''
mdl.add_constraints(isinstance(w[i]/5, int) == True for i in range(0,5))
'''
where w is defined as follow :
'''
w = mdl.integer_var_list(5,5,30,…
Yassine
- 11
- 2
0
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1 answer
Populate() Equivalent for MIQP in CPLEX
I'm trying to solve the MWIS problem exactly using CPLEX. When I try the .populate() I get the error that docplex.mp.utils.DOcplexException: Model.populate_solution_pool only for MILP problems, model 'Exact Solution' is a MIQP.
Is there a way to…
jolene
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0
votes
1 answer
How to use CPLEX Multi-Objective (ObjectiveSense) parameters
I am working on pure LP problem and using Multi-Objective to solve it. When I am using objective with weights:
solver1.minimize( A* 1000
+ B* 10000
+ C* 100
…
Kartik Kaushik
- 19
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votes
1 answer
How to stop DoCplex.CP solver after finding each feasible solution?
Dears,
Currently, I am using OPL-DoCplex to solve a problem using CP. The basic model was built in OPL then I called it into python by DoCplex. I have the following questions:
1- In the OPL model, there are decision expressions (dexpr) that were not…
Mohamed Menessy
- 27
- 3
0
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2 answers
CPU time in docplex - Python
Let us assume that I have created a mathematical model in python and want to solve it using the below code (the docplex library.)
start = time.perf_counter() # CPU time calculator of the CPLEX solver
# Obj 1
mdl.minimize(obj1)
solution =…
mdslt
- 155
- 1
- 10
0
votes
1 answer
Reset the values of variables in docplex - Python
I have a mathematical model ('mdl'), and I want to solve it in an iterative manner using the docplex library in python, like the below simplified example:
mdl = Model("LTC")
x = mdl.binary_var_dict(set_idx1, name="x")
#model defined here
for i in…
mdslt
- 155
- 1
- 10
0
votes
2 answers
multiple models in cplex - python
I want to implement the epsilon constraint method, where I need to have multiple models with similar variables and almost identical constraints. I was wondering how I can define a variable (or constraint) that I can use in all models. For example,…
mdslt
- 155
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0
votes
1 answer
CPLEX - Optimization - Minimize production cost by period: Error: Model is non-convex
I'm trying to create an optimization model using CPLEX.
My problem is:
I have demand, production capacity (by machine by day), and production cost (by machine by day) to produce the products.
Some machines have diferent cost and production capacity…
0
votes
1 answer
Is it possible to evaluate a cumul function at a specific moment in time in CPLEX?
I'm trying to add a minimization criterion of accumulated capacity usage throughout time.
The capacity usage is modeled using a cumul function, consisting of a summation of pulse() functions, where each scheduled interval would contribute to the…
Tortidip
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- 3
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votes
2 answers
DOCPLEX MIP warmstart
I am trying to solve a large MIP scheduling problem. Since it will take a long time to solve the problem, I want to run the same model with fewer event point and find its n-th solution. Use that solution as an initial solution/seed for a bigger(more…
Abilash
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