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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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Optimizong billboard placement

I have a table of a 18,000 billboards with an ID, latitude, longitude, Impacts(the amount of people that see the billboard in a…
David Esquer
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Finding overlapping areas in Julia grid system performance question

I am currently attempting to calculate a specific type of set of locations within a grid. The problem at hand is related to a 2D packing optimization problem. When packing items, I need to select a position (i,j) in the grid for the item. Due to the…
AliG
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Transportation cost optimisation using OMPR for a large data set

I am solving a transport optimization problem given a set of constraints. The following are the three key data sets that I have #demand file demand - has demand(DEMAND) across 4821(DPP) sale points(D) head(demand) D PP…
Srikanth Viswanathan
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Using NewBoolVar in Google OR-Tools

I am wondering the syntax for logical constraints in Google OR-Tools. I have a nurse scheduling project I have done in CPLEX that I am translating over to Google OR-Tools. I have come across the documentation for channeling constraints in Google…
Steve White
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Unbounded Knapsack with multiple bins and constraints

I'm new to Python coding and need help to solve an unbounded knapsack problem with multiple bins (4 bins) and constraints. The bins have weight constraints of 10.5, 10.5, 7, and 7 respectively. Each bin can be filled with certain items only. For…
Ben Morrow
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Could this CP-SAT model be faster?

My team is building a CP-SAT solver that schedules assignments (think homework) over a period of days with variable availability (time available to do assignments). We're trying to speed up our model. We've tried num_search_workers and other…
Eli
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Branch and Bound VRP has zero nodes

I'am trying to solve the VRP with Gurobi and therefore analyse the branch-and-bound tree, but Gurobi solves the problem in the root and doesn't use branch-and-bound (0 nodes explored). Is there a possibility to start the algorithm without…
Jack
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Automate creating Piecewise objects with a for loop

I have an optimization formulation where I have multiple decision variables, each decision variable has its own quadratic cost function term. I am planning to use a piecewise linear approximation to simplify the objective function through using the…
Aziz A
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Issue with Integer Linear Programming using PuLP

I am trying to solve this ILP using PuLP. Problem states that we need to minimize the cost of building a warehouse. We need to decide which warehouse to build based on the lowest cost. Here is what the LP looks like min ∑transportcost * X_i, …
Umang Mistry
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schedule algorithm for minimal contact time and group size for my child's daycare

Given the new legal regulations due to covid-19 the daycare of my child and all involved parents are overwhelmed and we need to come up with a schedule of when which child can be cared for. Given the demanded care time per child (s. below), We need…
Stuck
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Google OR-tools VRP - Pickup/Dropoff at same node

I'm currently using Python and the Google-Or-Tools to solve an VRP problem, that I am not sure how exactly to model. (If someone has a solution with another library/tool, absolutely interested as well) Problem Statement: I have basically the…
Tobgen
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Dual infeasible due to empty column 'x1' in Python w/Cplex/Docplex

I would really appreciate any input for this optimization problem: I am failing to assign my variables the values 1,2,3,4,5 for i and j, I think that is why I am getting this error: Dual infeasible due to empty column x1. Am I on the right…
jopro
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Proper way to write a complex objective and constraints in Python Pulp

I am following a book that explains advanced linear programs. So far it's been good, but this example has me stumped on how to properly write the objective functions and constraints. Below you'll find my attempt at coding the left coefficient but…
dassouki
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ompr MILPModel : non-numeric argument to binary operator

I am familiar with how to use ompr::MIPModel but am trying to learn how to use MILPModel to take advantage of the model build speed. A simplified version of my model is below. I have two decision variables, x and y, binary and of equal length. I…
Ralph Asher
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Capacity Constraint Check only at node level in OR-Tools

We have combined the pickup delivery module with capacity constraint. Here, we keep on picking up and dropping the items on the route (there can be pickup and drop on the same node). Hence, a person will be able to take more orders even though his…
nik
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