All Questions
Tagged with cplex integer-programming
47 questions
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How to define this complex labor rule as a constraint in MIP?
Im trying to define a complex labor rule as constraints in a MIP, solved with CPLEX.
My key decision variable is a binary x(i,j) indicating if shift i is assigned to employee j.
The labor rule is as ...
2
votes
1
answer
246
views
How to set Gurobi to stop after the objective value reaches a certain threshold in Julia?
I am trying to run a minimization problem for an MIP using Gurobi in Julia. I would like it to stop after it has found a solution that is below a certain threshold that I have set. I have found ways ...
- 21
0
votes
1
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71
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Truck Type (infinite number of them) vs Orders
The goal of the docplex model below is to choose the trucks with total minimum cost to fulfill all orders. I treat the truck type as 1 truck in the following code, but in fact, a truck type can have ...
- 18.6k
0
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1
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368
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CPLEX won't display decision variables after successful solution
I set up a code for a course scheduling optimization problem using IBM CPLEX.
The decision variable is dvar boolean x[course][roomtype][timeslot];, where x is 1 if the course takes place in a room ...
0
votes
1
answer
96
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How do I run a simulation experiment (iterative procedure) in CPLEX?
I am a beginner of programming. I'm trying to practice run a simulation with CPLEX.
Since I want to be a person who wants to work in an area in optimization.
Therefore, I am trying to study some ...
0
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1
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746
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what's the difference between optimal solution of cplex and the optimaltol solution of cplex？
what's the difference between optimal solution of cplex and the optimaltol solution of cplex？
1、When I solve a integer programming model with CPLEX solver, the result status of some instances show ...
0
votes
1
answer
502
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Need to speed up the operations on numpy arrays in python
I am solving an integer programming model by importing Cplex as a library in Python. Let's say the optimization problem has a constraint in the following form (Ax = b):
x0+x1+x1+x3 = 1
The indices of ...
- 161
1
vote
1
answer
283
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Run callback only at the root node
I'm solving an integer linear programming problem with CPLEX 12.7 using a branch-and-cut framework. I'm using the CPLEX callable library in C++.
Therefore, I implemented an UserCutCallback callback. ...
- 410
0
votes
1
answer
380
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How to clone a cplex object in Java?
I am solving a problem in Java using the CPLEX library. I use a class "Model" to create a CPLEX object, and add to it variables, objective function and multiple constraints. This is the ...
0
votes
1
answer
288
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Why does CPLEX set unrelated variables as 1?
I have been working on a combinatorial optimization problem which can be modeled as an integer linear programming. I implemented it as a c++ project in visual studio 2017 and CPLEX1271. Since there ...
- 361
0
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1
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83
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Problem with binary decision variable constraints in VRP
I would like to create non-linear violation costs in my VRP. I already created my whole VRP with time windows in which I have these decision variable:
dvar float+ w[N][D]; // violation time for late ...
- 1
0
votes
1
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921
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Cplex Error: Adding trivial infeasible linear constraint
I want to solve an integer programming model with cplex python. I have this model:
a and h are matrixes with 0s and 1s. p is a set of numbers.
here is a part of my cplex code for this model:
p=[i for ...
- 81
0
votes
1
answer
176
views
Inequality Constraint x Upper Bound Definition on Variable Declaration
Which is more computationally efficient for a Mixed-Integer Problem Formulation:
a. State the upper and lower bounds of the variables when declaring the variable
b. Declare the variables with the ...
- 97
0
votes
1
answer
52
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How can I make a variation limits, do not exceed a specific value
Now I am facing a problem that making a variation does not exceed a specific value.
I will describe in details below.
using CP;
int a = 4;
int b = 3;
int c = 5;
range arange = 1..a;
range brange = ...
- 25
0
votes
1
answer
719
views
How to solve this error when I use CP in Cplex
Now, I am facing with an error.
'Decision variables of type dvar float not supported by this algorithm.'
Here is the code that I made.
I will write it simply.
Firstly, I got in trouble with error ...
- 25