# All Questions

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### CPLEX allows manually inserted solutions to violate lazy constraints

I am using CPLEX 12.9 to solve a mixed integer linear programming problem. Some of my constraints are enforced through a legacy LazyConstraintCallback. Heuristic solutions are inserted through a ...
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### Why isn't $x_2+x_3+x_4\le 2$ a cutting plane?

In my textbook, to generate cutting planes, they tell you to proceed as follows: A procedure for generating cutting planes: Select a ($\le$) constraint that has only nonnegative coefficients. ...
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### Dynamic programming example

I am going to buy a family car at the beginning of the New Year. I am going to stay in the UK for the next 4 years. I am considering the possibility of being a customer of company A which sells ...
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### LP sum of variables that are above a threshold

I am trying to code a constraint of the form: $$\sum_i y_i < K\,\text{where}\,\begin{cases}y_i = x_i\quad\text{if}\,x_i>k_i\\0\quad\text{otherwise}.\end{cases}$$ In other words, I want to ...
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### Tools to implement branch-and-price algorithms

As far as I know, implementing a branch-and-price algorithm is a task far from trivial. However, there are tools such as SCIP or the BCP framework of COIN-OR that help implement such algorithms. I ...
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### Travelling salesman problem with given number of locations to visit

There's a great example here of how to find a solution to the travelling salesman problem: ...
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### Integrating genetic algorithm (or other heuristic methods) with CPLEX

[Topic to discuss GA and CPLEX] I've seen some papers trying to integrate genetic algorithm with CPLEX, such as here and here. Although they integrated both, it is done in 2 different steps; that ...