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Questions tagged [operations-research]

Operations Research is the application of quantitative techniques to decision making, typically involving mathematical optimization. Problems include dynamic programming, linear programming and Integer programming & discrete optimization.

Operations Research is the application of quantitative techniques to decision making, typically involving mathematical optimization. A problem is modeled as a math formulation, and the solution obtained via a solver. Problems in OR include dynamic programming, linear programming and Integer programming and discrete optimization.

The other names for Operations Research (OR) include Decision Science, Management Science, or Operational Research.

The Wikipedia page on Operations Research. INFORMS, the society for OR practitioners has a lot of relevant information.

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Interpreting Weibull parameters from survreg

I am trying to generate an inverse Weibull distribution using parameters estimated from survreg in R. By this I mean I would like to, for a given probability (which will be a random number in a small simulation model implemented in MS Excel), return…
DavidT85
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Which solver do Googles OR-Tools Modules for CSP and VRP use?

I am currently evaluating googles or-tools and just noticed that it's not really a solver on its own but mainly an interface to other solvers. What I'd like to know is which solvers this framework uses for constraint and routing problems. I have…
javaguy
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Reinforcement Learning vs Operations Research

I was wondering when one would decide to resort to Reinforcement Learning to problems that have been previously tackled by mathematical optimisation methods - think the Traveling Salesman Problem or Job Scheduling or Taxi Sharing Problems. Since…
Antonia Calvi
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Interpretation of GAP in CPLEX

This is a part of the engine-log output that I get from a small-scale mixed integer linear optimization problem that I solved in CPLEX 12.7.0 Nodes Cuts/ Node Left Objective IInf Best Integer …
Riegsche
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Voronoi Tessellation in Python

Node Assignment Problem The problem I want to solve is to tessellate the map given with the Blue Nodes(Source Nodes) as given input points, Once I am able to do this I would like to see how many Black Nodes(Demand Nodes) fall within each cell and…
user1071530
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How is hits@k calculated and what does it mean in the context of link prediction in knowledge bases

I study papers on link prediction in knowledge networks. Authors usually report "Hits@k". I wonder how to calculate hits@k and what does it mean about the model and the results?
SilentFlame
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scipy minimize SLSQP - 'Singular matrix C in LSQ subproblem'

I'm trying to solve a pretty basic optimization problem using SciPy. The problem is constrained and with variable bounds and I'm pretty sure it's linear. When I run the following code the execution fails with the error message 'Singular matrix C in…
puffadder
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Open source alternative to Mosek?

Is there an open source alternative to Mosek? Basically, I'm looking for large scale convex optimization solver packages. Thanks! EDIT: Forgot to mention earlier, problem is non-linear; mostly quadratic, but occasionally may need non-quadratic…
anon
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Finding strongly connected subgraph that contains no negative cycles

Is there an algorithm that solves the following decision problem: Given a strongly connected weighted directed graph G, defined by its transition matrix, is there a strongly connected spanning subgraph of G that has no negative cycles? A strongly…
hola
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NP-Completeness in Task Scheduling

So this is a bit of a thought provoking question to get across the idea of NP-Completeness by my professor. I get WHY there should be a solution, due to the rules of NP-Completeness, but I don't know how to find it. So here is the problem: The…
Herp Derp
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Gas Station Problem - cheapest and least amount of stations

I am working on a problem that consists of the following: You are driving a car with a certain fuel usage m (in our example we will take 8l/100km) and you are driving a straight of length x (example: 1000km). The car starts out with a certain amount…
Articdive
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Integer programming: Is it possible to define an incompatibility constraint?

I'm using jsLPSolver to solve an integer-programming problem. I'm having trouble adjusting the model to contain incompatibility constraints. I've got the following model: { "optimize": "cost", "opType": "min", "constraints": { …
tetri
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Weighted Bin Packing/Knapsack optimization

I'm struggling to categorise a problem that I'm working on, which means that I haven't been able to figure out if there's any established heuristic solutions. What sort of problem do you think this is, and how would you recommend I solve it? I have…
thornate
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how to print a model to file with JuMP/Julia

The function print(model) outputs the model in the console. How can I print the model in a file (e.g. lp file) ? Best Michael.
Michael
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No solution in CPLEX with very small change in inputs

I'm using CPLEX in C++ to solve a hub location problem, a MIP, and I've recently found a very precise set of inputs that CPLEX thinks is infeasible (i.e. CPXMIP_INFEASIBLE) even though the problem is certainly feasible. The problem appears to…
mobeetsatwork
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