Questions tagged [r]
For questions about solving Operations Research problems using the R programming language.
24
questions
2
votes
1
answer
48
views
Is it possible to merge two objective functions using the LpSolve package in R?
I have been using the LpSolve package to solve a minimization problem in my final course work, but I need to reconcile this problem with a maximization problem. Conducting several researches, I ...
2
votes
1
answer
84
views
3D Knapsack Problem: R or Python Packages?
For an upcoming client project, I'm looking to do a 3D variant on the knapsack problem. Basically, there's a bin of dimensions $x,y,z$, and I have $K$ units of an item with dimensions $a,b,c$. (...
- 661
3
votes
1
answer
65
views
Application with VIKOR multicriteria method
What to do in these cases where I can't rank by the VIKOR multicriteria method because Q has no value?
...
- 227
0
votes
1
answer
61
views
Conflicts with weights of the topsis method in R
Why can't I generate for the topsis method, choosing a w <- c(1, 0)? As far as I know it has to be the sum of the weights ...
- 227
6
votes
3
answers
127
views
Linear Programming problem for finding supplier
I have a linear programming problem in front of me that I am searching to solve in R (any package), seems like an unbalanced assignment problem to me with relaxed constraints on columns (repeated ...
- 183
1
vote
0
answers
27
views
How to utilize Spearman Rho coefficient
The dataset below presents the ranking of different multicriteria methods. My idea is to generate a final ranking based on the multicriteria methods for all alternatives, but it can be seen that in ...
- 227
2
votes
1
answer
56
views
Using VIKOR multicriteria method in R
I'm using the VIKOR multicriteria method from the MCDM package. The example can be found here: https://cran.r-project.org/web/...
- 227
1
vote
0
answers
45
views
How to use PROMETHEE multicriteria method in R
I used TOPSIS multicriteria method to select the best number of clusters out of the 34 options. As weights I used 0.5 for each criterion. The ...
- 227
1
vote
1
answer
63
views
How to Use the Weighted Sum Method in R
I would like to use the weighted sum method to select the best number of clusters out of the 34 options. As weights I would like to use 0.5 for each criterion. The coverage criterion is to minimize ...
- 227
1
vote
1
answer
64
views
Use the Weighted Sum Method in R
I would like to use the Weighted Sum Method (Multi Criteria Decision Making) in R in this database below. The resolution of the issue is here: https://www.geeksforgeeks.org/weighted-sum-method-multi-...
- 227
4
votes
2
answers
123
views
R package for multi objective integer evolutionary algorithm
I have a discrete event simulation (simmer package) based on probability distributions in R. I would like to optimize the variables according to several (2 or more) objectives. I used the NSGA-II ...
- 41
2
votes
2
answers
86
views
How to use `cplexAPI` to solve quadratic programs/quadratically constrained linear programs?
I am trying to use cplexAPI to solve quadratic programs or quadratically constrained linear program.
While it seems to be pretty straightforward to use ...
- 21
4
votes
2
answers
163
views
Optimizing a capacitated clustering problem with Greedy search algorithm
So, I am trying to implement a greedy search algorithm to cluster a number of points. Each point has a specific demand and each cluster shouldn't exceed that demand. Now, when I run it for a smaller ...
- 397
3
votes
0
answers
117
views
How to approach this Truck Utilisation problem?
The problem statement currently I have is very broad (or you can say very vague at the same time):
I have a number of dropping locations (Customer locations)
I have the location of the HUB
I have a ...
- 397
5
votes
4
answers
458
views
Solving Capacitated VRP with multiple various sized vehicles
I am looking to form a Capacitated VRP problem like this:
I have 40,000 dropping locations with Demands of each point available
I have 5-6 types of vehicles available with different capacities and ...
- 397
3
votes
1
answer
123
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
0
answers
78
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] ) ...
- 661
3
votes
1
answer
366
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 ...
- 661
3
votes
2
answers
157
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 ...
- 663
5
votes
3
answers
192
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 ...
- 151
5
votes
2
answers
1k
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 ...
- 371
6
votes
1
answer
107
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 ...
- 447
9
votes
2
answers
188
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 ...
- 2,009
5
votes
2
answers
558
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 ...
