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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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Pyomo: How do I add all set of a model's constraints to another model?

I want to add all constraints and variables from a model to a different model in Pyomo, but I cannot figure out how. The use case is when I want to transform my model to its dual, and I need to add all dual constraints and variables to the primal…
AliRa
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How to write Simplex method (in tableau/matrix form) from scratch in python?

I have got my equations and everything set. I just don't know how to iterate, i.e. how to update A, b and c. I have been trying with the matrix form. If anybody could help with that or the tableau form, it would be amazing! My problem is simple: min…
huy
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Trash scheduling model for AMPL

I have been working on a grabage collection problem in AMPL and these are the data: Variables Schedule and Garbage Collected Obj fun : minimize total operational costs Constraints : Each shift should not work for more that 8 hrs The garbge…
Wayne Þunraz
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Reading material suggestions for algorithmic routing

We're starting to look into a problem at work that effectively boils down to the following problem: Let's say I have red people and blue people arriving at a store. Red people are eligible to buy products A and B, and blue people are eligible to buy…
Moderat
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linear programming problem for minimum cost

A construction company has 6 projects, for each they need $d_i$ workers. The company has no workers at the beginning of project 1. Each new worker must take a safety course that costs 300, and 50 more for each worker. If there is no new worker there…
Roi Hezkiyahu
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Represent forall operation in Ortools

I am trying to solve a production scheduling problem in Ortools. The problem contains parallel machines. I have created a variable called all_task just like in standard example at https://developers.google.com/optimization/scheduling/job_shop but…
Swastik
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How can I improve my SA algorithm that I used for job scheduling?

objective: max sum(solution(i,9)) --------------------------------------------- while T>Tmin for iteration=100 for i=1:61 function(generate_possible_solutions) random_value = generate random value solution(i) =…
atco35
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Computing White Speckle Metric in a Document Image

The paper 'Metric-based No-reference Quality Assessment of Heterogeneous Document Images', discusses about measuring the quality of characters in a document image. I'm having difficulty to understand the white speckle metric in page 7. Small white…
alyssaeliyah
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what is the error in my code ? I have not set the data already

i was trying to solve this transportation problem in cplex enter image description here here is my OPL code int p=...; int q=...; range i=1..p; float a[i]; range j=1..q; float b[j]; float c[i][j]; dvar boolean x[i][j]; minimize sum(l in i,m in…
sudarsan vs
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Cp-Sat AddAllDifferent vs add constraint

Dears, I have a model with two boolean decision variable, avere only one can be equal ti 1. Is it the solver faster if I use AddAllDifferent or It i use a simple constraint (ADD) x+y=1?
stefano guerrieri
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How to formulate discrete-time resource scheduling into problem?

I'm new to linear programming and trying to develop an ILP model around a problem I'm trying to solve. My problem is analogous to a machine resource scheduling problem. I have a set of binary variables to represent paired-combinations of machines…
MichaelC
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Modeling the Objective Function in the CPLEX Java API

I#m trying to model the objective function sum(i in Sites,j in Sites, k in Routings)(c[i][j] * x[i][j][k]*TruckKmCost) in Cplex using java. IloLinearNumExpr expr = cplex.linearNumExpr(); for (int i = 1; i <= nbFarmer; i++) { …
nona
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How to partition a graph, so as the weight of the nodes in each partition would be between two numbers?

There is a specific problem in operations research that is converted into a graph: I would like to partition the graph into n sub-graphs, so as the nodes in sub-graphs are connected, and the sum of the weights of the nodes is between two numbers, a…
AliRa
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Modelling an IF-THEN statement with multiple conditions in Mixed Integer Linear Programming (MILP)

I need some help modelling the following logic as a mixed integer linear programming constraints for a vehicle routing problem. The Variables involved are the following: Xij, SDVlmj, and MDVhkbj are binary decision variables. They equal to 1…
gravityman123
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Focussing on maximum orders picked up from a single store

Currently, if a customer orders 2 products, suppose, 1 product is present in Store 1 which is 20 miles away from customer location and both the products are present in Store 2 which is 30miles away from customer's location,1 product available at…
Gayatri Padhi
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