2,362 questions
0
votes
2
answers
38
views
Docplex: KeyError: (-1, 0) when attempting to add a constraint that makes the first value have to equal the last
Part of my model states that the initial value of a time series should always equal the last. When modelling this for just one time series, the constraint is added no problem.
m.add_constraint(var_1[-...
- 23
0
votes
2
answers
84
views
Installing IBM ILOG CPLEX academic version for use with python
I am struggling to activate the academic version of CPLEX for use in docplex. I had tried following the steps outlines in https://www.ibm.com/docs/en/icos/22.1.2?topic=cplex-setting-up-python-api, but ...
- 23
0
votes
1
answer
97
views
IBM CPLEX does not have a python folder on install
I have installed IBM CPLEX Studio 2212, and am attempting to verify that I have installed the academic version to remove the limit on DOCPLEX. However, upon install there is no python folder in the ...
- 23
0
votes
1
answer
28
views
Docplex use for timeseries based variables
I am trying to model an optimisation problem where each item in a list is essentially power generated at that hour. I am trying to minimise the amount of energy stored while still getting the same ...
- 23
0
votes
1
answer
35
views
Docplex and callback problems
I’m trying to implement a custom callback that solves a subproblem during the optimization process. I want to:
Get the values of certain variables from the main model's solution.
Solve a subproblem (...
- 3
-3
votes
1
answer
37
views
How can I write the values of a decision variable to an Excel sheet after running an iterative optimization in CPLEX OPL?
I am performing an iterative optimization using the main function in CPLEX OPL. After each iteration, I want to write the values of the decision variables to an Excel sheet. The optimization runs for ...
0
votes
0
answers
50
views
How to write flow constraint for destination node if I have to stay at destination for some time and then move towards other destination node
A team travels by car from a source node to a destination node, passing through intermediate nodes based on a predefined network. Upon arriving at a destination node, the team is required to stay for ...
-1
votes
1
answer
22
views
Download and Installation of cplex/docplex academic version
I recently downloaded the latest version of IBM ILOG CPLEX Optimization studio using my Academic credentials. However upon installation, there is no python folder with the setup.py file that would ...
0
votes
1
answer
39
views
How can I update a matrix in the current iteration while preserving the values from previous iterations using the main function in CPLEX OPL?
I want to update a matrix with values of the current iteration as well as the previous iteration in the main function. Please help me in achieving this. I have tried this code.
int TSlots = 96;
...
2
votes
1
answer
36
views
How to update a matrix in iterative optimization using cplex opl?
I am solving an iterative optimization problem in cplex opl using the main function. However, I am getting errors while printing a matrix value. Please help me in solving this issue.
int Nod=41;
...
0
votes
1
answer
29
views
Reduced Costs in IBM ILOG CPLEX Optimization Studio
In this Stack Overflow post, they give the code to find the solution duals (shadow prices).
execute
{
writeln(ctMaxTotal.dual);
writeln(ctMaxTotal2.dual);
writeln(ctMaxChloride.dual);
}
What is the ...
1
vote
1
answer
23
views
How to include .dat file while writing a code in cplex opl using main function?
I am trying to solve an iterative optimization problem in cplex opl using main function. The optimization objective and constraints are written in subvaluenew.mod.
float maxOfx = ...;
dvar float x;
...
0
votes
1
answer
35
views
How to update non-decision variables/parameters Iteratively in CPLEX OPL using main function?
I am running a CPLEX OPL model for 10 entities. The objective is to optimize a certain objective for each entity.
Step 1: The CPLEX model first runs for the first entity, optimizing the objective ...
0
votes
1
answer
43
views
Limit the memory used when solving using docplex
I am implementing a mathematical model using docplex and the academic version of CPLEX.
I am attempting to solve very big problem instances.
I faced a MemoryError.
Is there a way to overcome this? I ...
- 132
0
votes
1
answer
28
views
How to solve the error cplex can't extract expression?
For a given problem, I am writing the following constraint. But I am getting the error as cplex(default) can't extract the expression :
forall(v in VehicleRange){
slot==startSlot[v];
tm==...