Questions tagged [r]

For questions about solving Operations Research problems using the R programming language.

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3
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0answers
31 views

R ompr MILPModel array multiplication?

In R, I regularly ompr::MILPModel for optimization. I adapt the below snippet to enable multiplication of a decision variable with two dimensions (e.g., x[i,j] ) ...
3
votes
1answer
227 views

Non-numeric argument to binary operator in MILPModel of ompr package

I am familiar with how to use ompr::MIPModel but I am trying to learn how to use MILPModel to take advantage of the model build ...
3
votes
2answers
137 views

Using R for coding Matheuristic for Research Publication

Given that R possesses superior data pre-processing and post-processing packages, I am thinking of coding a matheuristic using R for publishing in an academic research journal. However, I am unable ...
5
votes
3answers
182 views

Reducing number of suppliers for product portfolio

I have the following matrix of suppliers who are able to make a certain product, against all products in my portfolio. What is the best way of finding the solution to "the least suppliers necessary ...
5
votes
1answer
707 views

VRP package for R

I work almost exclusively in R and Rstudio, and have found it to be an excellent ecosystem for data analysis and OR, including discrete event simulation, Monte Carlo simulation, MILP, and the ...
6
votes
1answer
91 views

DAG shortest path in R - I have a list of nodes, each node's completion time and each node's predecessor(s). How can I turn this to a list of arcs?

Without trying to manually sketch out a graph on paper, is there a simple way I could get the arcs between nodes in this problem? I am using R and it seems there must be an elegant way of doing so but ...
9
votes
2answers
153 views

When should I use a solver for IP and MIP and can I just use a library from Python, R, Matlab, etc…?

Are there any rules of thumb for figuring out when you need to use a solver like Gurobi or CPLEX, and when you can just solve you problems directly with a Python, R, or Matlab package? Is it just a ...
4
votes
2answers
255 views

Queuing models in R, $\lambda$ Little

It's noted that the number of folks in a stationary system will maintain an average equal to the rate of arrival multiplied by the mean of the service distribution. The formula $L = \lambda w$ is ...