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Questions tagged [docplex]

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.

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How can I use sqrt for a quadratic expression in Docplex?

I have Recently developed a code fo an MIP model in Python. I have used Docplex to optimize that, but I have an error that says: "TypeError: must be real number, not QuadExpr". Could you please tell me how can I calculate the sqrt and help me to fix…
Nasser Tarin
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CPO Save Log/Intermediate solutions

I am using the python API of CPO Optimizer. Is there any way to save the log/intermediate highlighted solutions and timestamps to build a chart on the evolution of the optimization? Thanks in advance! I haven't found a workaround so far, but…
Javi Pernas
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Getting approximate float values for some integer variable in Python

I've recently installed the Docplex optimization package on my Python to solve a problem. Then, I defined some integer and binary variables for the problem. But I've got approximate float values for these variables after running! I will explain more…
Nasser Tarin
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Is it easier to rewrite a pyomo model into a Docplex or a Gurobi model?

I've got an optimization problem written in pyomo that I want to translate to Qiskit. The only issue is that Qiskit has the ability to take in Docplex or Gurobi models. My question is this: Is it easier to rewrite a pyomo model into a Docplex or a…
Ahmad Bennakhi
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docplex - get relaxation objective value

I am trying to get the objective value of the relaxation of a MIP model with cocplex. Is there a way to find this value without relaxing the model and solving it an extra time ? This library might to the job but I can't manage to make it work.
Agathe L
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Conditional constraints in R

I am solving in R using GLPK a classical optimization problem: min c*x s.t. Ax<=b Where x is my vector of variables, c is a vector of constants, A is the constraints matrix and b is the constraints vector. Now my professor wants me to add the…
Vimar
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writing down a constraint in IBM CPLEX

My question is about writing down a constraint in IBM CPLEX or in any solver. Imagine you have a graph with N nodes and E edges. Imagine for connecting one node (source node) to another specific node (destination node), you have a set of paths. Each…
Shahrooz Pooryousef
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Why add_sos1 method of docplex is taking too long?

I am trying to maximize the absolute distance of binary variables from 0.5 in a relaxed form of a MIP model to push the solution to integer values as much as possible. For that I have linearized the absolute expressions (|0.5-y|) using the…
Vahid
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What is this default tolerance value for Binary (as well as other types of) variables in CPLEX?

Elaborating on the question, say the optimal solution has a few binary variables which are assigned to 0's and 1's; in reality when comparing these variables,we will often get their values as slightly higher or lower than what they should be…
S_Banerjee
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I am looking for an code for the "Truck-drone vehicle routing problem" solved in the CPLEX OPL or in Python

Here is mathemetical model. enter image description here Here are the details: depot: 1, truck: 10, capacity is 20, Customers: 50, Customers demand: 30 here is what I have tried so far: {string} k = ...; // vehicles {string} i = ...; //…
HnM
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Compute objective function in CPLEX

I am trying to solve the supplier diversification problem by minimizing the costs. I basically have a list of pricing for an item from different suppliers. The suppliers are willing to give me some discounts if I order in large quantities. I am…
M Germanos
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CP Optimizer CPLEX - Multiple optimal solutions

I am currently using the Python API of the CP Optimizer of CPLEX to obtain the optimal solution of a scheduling problem. Depending on the instance, there might be multiple equivalent optimal solutions. I would assume that during the searching…
Paulo Nascimento
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Manual Benders Implementation on docplex

I am using a manual Benders implementation for a problem. For that, I need to store certain variables since I need to transfer them to sub or master problems. However, as the size of the problem gets larger, it becomes really slow. I define those…
diabolik
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How to retrieve output data as JSON from IBM Watson cloud

I am solving a decision optimization problem using Cplex solver (Docplex) on IBM Watson Cloud. However, I got stuck trying to adapt the output format. Available documentation provides the following function to include in the main file in order to…
Yasmine
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Converting continuous variable dict to binary variables in python docplex

I have defined a continuous variable as follows: #Define sets X = [(i, j) for i in range(1, a + 1) for j in range(1, b + 1)] # Define variables x = m.continuous_var_dict(X, name="x", lb=0, ub=1) Is it possible to convert it to binary variable,…
diabolik
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