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Parallelization of an existing Adaptive Large Neighbourhood Search Heuristic

I am solving (or say, trying to find good solutions for) an arbitrary combinatorial optimization problem, think of it as a Vehicle Routing Problem with a bunch of side constraints that are not relevant for this question. I coded an Adaptive Large…
Albert Schrotenboer
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Algorithmic gap for Hochbaum's (greedy) algorithm for (metric) uncapacitated facility location

In Jain et al. (2003)1, at the bottom of page 801, they construct an instance of (metric) uncapacitated facility location for which they claim the greedy (Hochbaum's) algorithm has gap $\Omega\left(\frac{\log n}{\log \log n}\right)$. The algorithm…
ydubey7
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Paper suggestions on local search algorithms

I am looking for papers (or any resources) that go deep into the details of implementing local search algorithms. I don't want an introductory paper on the subject. Rather, I would prefer a survey dedicated to the implementation issues or papers…
Approximations
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Advantages of IBM CPLEX Studio over CPLEX in MATLAB?

This question comes from the perspective of an MSc student new to both OR and programming OR problems in a MIP framework. My research has led me down this path of needing to program an optimization model using CPLEX and I am not entirely sure…
GrayLiterature
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Is it possible (or straightforward) to define many secondary problems in bilevel programming?

I am new to bilevel programming. I was wondering whether it is possible (or straightforward) to formulate a bilevel problem in which there are many secondary-level problems? An example might be a type of attacker-defender problem where there are…
Mertcan Yetkin
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How to maximize "contrast" between nodes on a graph?

I have an undirected graph such as the one shown below. I can make up to 3 choices about the color of each node. The edge weights are equal to the difference between the nodes, given by the "distance" between the colors chosen for each node. What is…
Ike348
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Intuition behind SOCP and why it sometimes can be solved more efficiently than without transforming it into a SOCP?

I was doing an assignment regarding turbine placements, where one has to write and solve a maximisation problem. As I was reading into the topic, I came across the fact that I could transform the constraints into an equivalent…
Snowflake
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Nonlinear integer (0/1) programming solver

I have the following optimisation problem.\begin{align}\max&\quad\sum_i\sum_j\sum_k x_{ji}y_{kj} \operatorname{cost}(i,k)\\\text{s.t.}&\quad\sum_j x_{ji}=1\quad\forall i\\&\quad\sum_k y_{kj}=1\quad\forall j\end{align} Please suggest any solver for…
Rajya
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How to monitor/debug an optimization model in a production environment professionally?

I have seen this question How to avoid having your optimization models rusting?, which is kind of related, but I am more curious about the actual monitoring and the initial design of the software in order to be able to find bugs/problems in a…
user3680510
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Conditional Controls in MIP Models

Innocently cross-posted at Mathematics SE I am developing a model that operates in the realm of mixed integer programming, although I am fairly unfamiliar with this area of mathematics at the moment. I am hoping to get some clarification on whether…
GrayLiterature
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What are the prerequisites for learning about operations research?

I'm finding myself needing to learn about operations research. I'm planning to just find a textbook (or some other medium, such as an online course) on OR and learn from there. But I don't think I have the needed foundations to even start…
James Ronald
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Does The Modelling Software Make A Difference Regarding A Solution?

I am relatively new to the world of OR as my first foray into this field has me solving a MINLP. Unfortunately, my model is unable to solve because it is too complex, and so my supervisor has suggested that they could help me to code it up in MATLAB…
GrayLiterature
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How can I initialize the Restricted Master Problem in Dantzig-Wolfe decomposition?

I am attempting to solve a linear program via Dantzig-Wolfe decomposition. It is the first time I implement this method. Before the pricing iterations start, I need to provide an initial set of columns to the Restricted Master Problem. I know I can…
k88074
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How to exploit known solution in MILP

I have an MILP model to which I get an integer feasible solution as a result of a heuristic search. In this particular example, the initial solution turns out to be the optimal solution, which I prove through B&B after solving 3000 LPs (20 Minutes…
Clement
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Modeling and solvers

I have just started to dive into OR world on my work. Currently we are using GAMS with Gurobi but some of us have strong programming background and would like to have more programmatic approach to OR. I have heard that without GAMS you can't get…
aurelije
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