Top new questions this week:
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For integer programs solvers (like Gurobi, Cplex, ...) report the value of the linear programming relaxation for integer programs, i.e.
Root relaxation: objective 2.648400e+02, 233 iterations, 0.01 ...
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I have seen some papers claiming that their proposed model is integer-friendly. I would like to get more information about what type of constraints we can call integer-friendly.
Probably, it can be ...
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I'm given two matrices:
$A$, an $n\times n$ adjacency matrix of a graph. The graph is unweighted, undirected and has no self-edges or multi-edges.
$X$, an $n\times n$ symmetric matrix of edge ...
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I have a product for which the monthly demand pattern for the last year looks like the following. The product is ordered only 22 days out of 366 days in batch sizes of 272 kgs. Since there are so ...
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I have algorithms that get me a tight upper (UB) and lower (LB) bound to a maximization binary integer program (a routing problem). My formulation is non-compact and requires the addition of sub-tour ...
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The Network - Maximum flow problem below aims to find the maximum flow using simplex method :
With the LP as follow :
LP : \begin{Bmatrix}
Z(Max) = \sum_{i=1}^{m} fi \\
Af =0
\end{Bmatrix}
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Greatest hits from previous weeks:
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When teaching introductory OR courses I have often found that presenting counter-intuitive or paradox-like results is a great eye-opener for the students. I use these examples and results as a ...
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In the set covering/column generation approach for the VRP (Balinski and Quandt (1964), or e.g. this tutorial), the basic idea is:
Generate some routes.
Solve the set covering problem using those ...
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Because of excessive pollution on the Momiss River, the
state of Momiss is going to build pollution control stations.
Three sites (1, 2, and 3) are under consideration. Momiss is interested in ...
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As a practical (real-world problems) point of view, it's important we could solve optimization problems as quickly as possible (for instance, to release a daily schedule).
Maybe a problem with many ...
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I’m interested in the idea behind this in general, so I thought this would be the best place to post, though I have a practical and semi-urgent need of allocating the points on my credit card towards ...
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About Polyhedra, Polyhedron, Polytopes and Polygon, what do they mean in the context of linear programming and what is the difference between them?
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What approaches can I use for a Linear Programming problem with the additional constraint that if a decision variable falls below a certain threshold, then it should just be forced to 0.
I'm ...
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