# Questions tagged [runtime]

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1 vote
1 answer
63 views

### Partially modify LHS of a constraint set?

I have implemented a column generation algorithm in Gurobi in Python. The most computationally expensive aspect of this algorithm is the reconstruction of the master problem when a column is added (or ...
1 vote
0 answers
34 views

### Is there a way to calcuate the maximum number of cuts in a Benders decomposition?

Since the benders algorithm is finite, there a maximum number of cuts that could theoretically be added. The worst case is that I add cuts for all extreme points and all extreme rays that are part of ...
3 votes
2 answers
243 views

### Reformulate bilinear binary constraint

I'm a solving a model that has the following constraint: $$c_{p,n} = \sum_{s\in S}\sum_{i \in \{1,2,3\} } x_{p,s,i-1} x_{n,s,i}, \forall (p,n) \in C$$ where both the $c$ and $x$ variables are binary,...
2 votes
0 answers
57 views

### Is it useful to consider metaheuristics for power flow optimization involving binary variables?

I want to optimize the power flow in a low voltage grid, with respect to customer requests for electric vehicle (EV) charging, but also avoid grid overload (basically, the formulation can be seen in ...
2 votes
2 answers
106 views

### Runtimes for benchmarking

For a study, I need to make runs to evaluate and compare performance of various models. To evaluate them I need to obtain their running times. I wonder if there is a rule to when to start and end ...
4 votes
1 answer
220 views

### Accelerating an integer programming model

I am working on a scheduling problem, where I am solving it through column generation. The pricing problem of this algorithm is an integer programming model as follows: F_1 \Big\{V^...
5 votes
1 answer
401 views

### Gurobi solver with multiprocessing does not reduce total solving time

Problem I use the syntax of gurobi with multiprocessing to solve multiple problems in parallel. Even though multiple problems are solved concurrently, the solving time for a single problem increases ...
0 votes
1 answer
284 views

### It takes a long time to solve excel gurobi-opensolver - is this normal?

The problem I have made associated with OpenSolver and Gurobi takes about 50 minutes to solve, is this normal? It has approximately 365 variables with upper and lower bands, the peculiarity is that ...
3 votes
1 answer
67 views

### studies to determine how much customers can wait to get outputs from a real time optimization model

I am building a web-based tool that needs to take input from the user and run an optimization model on a server and display results back on the webpage. Currently it is a MIP formulation solved using ...
3 votes
1 answer
652 views

### Why does the getTime() function from cplex concert returns wrong value?

I am running a MILP formulation (implemented in C++) with the Cplex Concert Technology 12.10, and I am trying to get the total elapsed time. So till the moment, I have tried three approaches: Be ...
7 votes
2 answers
291 views

### How to simulate computational execution time?

I am working with some computational experiments with an Integer Programming (IP) formulation over a well-known set of instances from the literature of my problem. And I would like to compare my ...
3 votes
0 answers
295 views

### Add Variables in Bulk for ortools

I am using the Python ortools to solve large LPs where the number of variables and constraints are in the hundred thousands ($10^5$). Surprisingly, it takes longer ...