All Questions
17 questions
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65
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My CPLEX Decision Variables shows "No Value"
Good day, I’m currently using the CPLEX Studio IDE v.22.1.0 for my university project and it’s my first time. I am working on “Reducing Overcrowding in an Emergency Department” by optimizing five (5) ...
0
votes
1
answer
31
views
How to represent a priority constraint in CPLEX Studio using OPL?
I am working on an optimization problem about the WFP where i basically have a set of countries where each contry belongs to a specific region. And each country is also represented by an Emergency ...
- 1
0
votes
1
answer
56
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Reading a nested array Using SheetRead from Excel file in IBM ILOG CPLEX OPL
I am trying to read a set of players P that play in position Q from excel. A sample of how the sets look is given below -
// set of positions q
Q = {"GK", "DEF", "MID", &...
0
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1
answer
52
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Needassistance Debugging " Data element already Been set" error on IBM ILOG CPLEX studio
I have made a model to optimize FPL team selection and tried running for 3 rounds of the season. However I am getting an error for the data set "Pq" which is the set of players p allowed to ...
0
votes
1
answer
368
views
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
views
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
votes
2
answers
502
views
CPLEX warm start with altered objective function coefficient
I am optimizing a MILP model in CPLEX (Python interface) that takes a long time to solve. Sometimes I need to do concurrent runs if my timelimit runs out. In order to continue optimizing with a ...
- 61
0
votes
0
answers
308
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MIP: Fixing a partial solution vector in CPLEX (C++)
I am implementing a matheuristic with CPLEX in C++, where I start the same MIP multiple times with different partial solution vectors provided.
However, I do not only want to provide a starting ...
- 374
0
votes
1
answer
881
views
CPLEX can't find a solution if I use binary vabriables
I'm using CPLEX 12.9 with Python to solve a MILP (Mixed-Integer Linear Problem).
I tried two approaches; I expected the same results, but while the first approach works, the second doesn't.
1) First ...
- 255
0
votes
1
answer
406
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CPLEX: How to run subset constraints in OPL?
CPLEX; Mixed Integer Linear Programming; Constraint Formulation:
There are 150 towns in the dataset, each town having several markets (or "mandis"). Total number of mandis in the dataset = ...
- 31
0
votes
1
answer
605
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LP / MILP formulation with OR logic
I'm solving a LP / MILP problem using ILOG CPLEX.
int n = ...;
range time =1..n;
dvar float+ c[time] in 0..0.3;
dvar float+ d[time] in 0..0.3;
dvar float+ x[time];
int beta[time]=...;
float pc[time]...
- 81
0
votes
2
answers
684
views
Complexity of Integer vs. Binary Constraints in CPLEX
Recently, I have been trying to learn a bit about CPLEX and was hoping someone could help me understand the complexity when solving for integer vs. binary constraints.
For example, say we are trying ...
0
votes
1
answer
115
views
How could I get a code for 'Ensure the Equipment continuing uptime and downtime process'
I am using CPLEX with OPL, and I have trouble specifying a constraint that I need in my model.
Equipment 'A' has a limit uptime to operate, 2 hours. It also has a downtime for maintenance, at least 1 ...
- 25
0
votes
1
answer
408
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How does docplex find the best bound?
I really can't understand how does CPLEX compute the best bound in the first place. From my understanding CPLEX needs to explore all the nodes in order to find the best bound or the objective value ...
- 982
1
vote
1
answer
742
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Where can I find the documentation of docplex automatic tuning tool?
I was able to find the documentation of the CPLEX automatic tuning tool, namely (the IBM Studio) but I couldn't find any for the docplex one (the cplex python api). Does the tuning tool exist for ...
- 982