Questions tagged [r]
For questions about solving Operations Research problems using the R programming language.
9
questions
3
votes
1answer
56 views
Problems with reading CPLEX LP models from file in R by package 'lpSolveAPI'
As an R user, I'm trying to read a CPLEX LP model from file by using the read.lp function from package lpSolveAPI.
Here's the command line (from within RStudio):
...
3
votes
0answers
34 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
261 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
139 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
183 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
816 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
157 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
294 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 ...
