Questions tagged [metaheuristics]

Questions on general heuristic strategies that can be instantiated for a specific problem to obtain a heuristic.

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2
votes
1answer
51 views

How to normalize the objective functions of multi-objective optimization into uniform form?

In my bi-objective model, the range of solution value for the first objective is large than the second objective. I decide to obtain a single solution by the weighted sum approach and solve it using ...
1
vote
1answer
44 views

Capacitated Facility Location problem with a dynamic set up cost

I am trying to solve a Capacitated Facility Location Problem (CFLP) with a dynamic setup cost in R. The problem statement is this: I have the transport cost The ...
2
votes
1answer
52 views

I didn't understand my problem with PSO and GA

I have a problem with three objective functions to be minimized, F1(interval value is [0,100]); F2(interval value is [0,100]); and F3(interval value is [0,20]). To solve my problem, I use Particle ...
-3
votes
1answer
92 views

Heuristic Algorithms Implementation

As a new python learner, I'm supposed to implement either GENETIC ALGORITHM or TABU SEARCH. Which one would be easier for me? Both of them are constructed for the same problem.
1
vote
0answers
105 views

Relationship between Hypervolume and population size, number of generations, and number of functional evaluations?

I have a multi-objective optimization with the following properties: Objective function: two non-linear functions and one linear function Decision variable: two real variables (Bounded) Constraint: ...
2
votes
1answer
120 views

Promising regions in optimization

I have investigated the literature, but I could not find proper explanations. As we know, (meta-)heuristics try to explore promising regions of optimality. The regions are then exploited. What is the ...
-1
votes
1answer
60 views

How to interpret velocity computation in Particle Swarm Optimization?

Please in PSO metaheuristic when we calculate the velocity what is the advantage of using pBest?
7
votes
2answers
457 views

Which approaches exist to solve a TSP?

Exists a list of categories that include possibilities to solve a travelling salesman problem (TSP)? I know, for example: Exact methods Integer Linear Programming Dynamic Programming Constraint ...
9
votes
5answers
318 views

Do better construction heuristics increase the performance of improvement heuristics?

Improvement heuristics for the TSP like 2-Opt need construction heuristics (also called constructive heuristics) like the Nearest Neighbour to start. Intuitively, I would say that a better ...
7
votes
2answers
290 views

Is there a ranking of heuristics for the travelling salesman problem?

Does a ranking of TSP heuristics exist that is based on the quality of the solutions? For example a paper or another resource that compares the performance of TSP heuristics like the nearest neighbour,...
1
vote
0answers
30 views

Run Pyomo model with externally assigned variables

I have several (large) Pyomo models with about 20 variables and parameters (as time series). Out of these variables and parameters I have 3 decision variables. Now my question is whether I can use ...
1
vote
1answer
110 views

Roulette mechanism with ALNS

I found in the literature that Adaptive Large Neighborhood Search (ALNS), which uses a roulette mechanism to select the best-performing operators, is the most efficient method. However, other ...
4
votes
1answer
121 views

How to improve the solution in ALNS metaheuristic

I am solving the CVRP with Adaptive Large Neighborhood Search (ALNS) . I used the following construction operators: GreedyInsertion and ...
2
votes
1answer
164 views

ALNS java code with the roulette-wheel-selection?

Currently I am coding the ALNS algorithm for the vehicle routing problem . I am stuck in the operator selection phase, I did not understand how I can apply this formula: $$p_i=\frac{f_i}{\sum_{j=1}^...
5
votes
1answer
113 views

Incomplete initial solution for capacitated vehicle routing problem

I am solving Capacitated Vehicle Routing Problem (CVRP) with Adaptive Large Neighborhood Search (ALNS) metaheuristic. I start my algorithm with a random initial solution, but the solution I get is ...
2
votes
3answers
511 views

Random solution for capacitated vehcle routing problem (cvrp)

I'm currently solving the capacitated vehicle routing problem (cvrp) with the approached methods (metaheuristics). In order to do this I have to build a random initial solution. My question is when we ...
4
votes
1answer
152 views

Calculate the average of the objective function values ​resulting from metaheuristics after a defined number of executions

I am trying to solve the capacitated vehicle routing problem (CVRP) with the ALNS metaheuristic. To test the performance of my algorithm I run it 10 times and I want to calculate the average of the ...
7
votes
2answers
115 views

Measuring performance of Genetic Algorithms

I'm looking for information concerning Genetic Algorithm (GA) outputs reliability. I've found some papers applying metaheuristics that have run their algorithms 30 times and got the best solution ...
1
vote
1answer
81 views

Looking for an example of a heuristic implementation in GAMS

I am new to GAMS and the documentation is not helping me to make fast progress. I am looking for an example implementation similar to Relax and Fix heuristic where in several iterations subsets of ...
2
votes
3answers
221 views

How to handle an equality constraint in metaheuristic algorithms (like GA, PSO)?

Metaheuristic algorithms are generally used to find the optimal solution to unconstrained optimization problems. I would like to maximize $x_1+3x_2-x_3\ge0$ while respecting the equality constraint $...
2
votes
2answers
149 views

Two Genetic Algorithms to solve two subproblems is a bad decision or I'm doing something wrong?

I'm developing a heuristic based on U-NSGA-III and GA for continuous variables with a crossover operator from this article: https://www.researchgate.net/publication/331451524_CAM-...
3
votes
1answer
133 views

PSO. Hyperparameter Optimization for Similar Problems

I am doing a project where I am using Particle Swarm Optimization (PSO) for a design optimization problem. Naturally, in there I had to conduct hyperparameter optimization to find the most optimal ...
-2
votes
1answer
106 views

Any references to the ROADEF 2020 Challenge?

The problem description of the challenge is given here. Does anyone has some references to similar problem. I would like to participate but I don't know where to start.
4
votes
1answer
172 views

How to represent time window as constraint in a vehicle routing problem

Hi I am trying to solve a vehicle routing problem using Tabu search, I have successfully completed implementation of constraints for CVRP by giving penalties to objective function , how do I implement ...
9
votes
3answers
276 views

What is good introductory literature on (meta)heuristics?

What textbook/articles would you use to introduce heuristics and meta-heuristics to OR students? Assume they have already seen some OR (e.g., LP and MILP).
15
votes
4answers
5k views

Which Python package is suitable for multiobjective optimization

I would like to start using Python for modelling and solving optimization problems. I would like to use both single-objective problems and multi-objective problems with a multidimensional objective ...
7
votes
2answers
889 views

Difference between exploration and exploitation in Simulated Annealing algorithm

In evolutionary algorithms, two main abilities maintained which are Exploration and Exploitation. In Exploration the algorithm searching for new solutions in new regions, while Exploitation means ...
4
votes
1answer
168 views

How to parallelize metaheuristics algorithms (Island Model)?

I have different metaheuristics (Tabu search, Simulated annealing, Iterated local search) solving an optimization problem (a variant of the resource-constrained project scheduling problem). Each ...
0
votes
1answer
1k views

How to solve knapsack problem with simulated annealing?

I was going through the course contents of Optimization with Metaheuristics in Python in udemy , where they have solved a quadratic assignment problem using Simulated annealing in python , i was ...
7
votes
1answer
133 views

How to solve this variant of RCPSP

We have $m$ projects in parallel that require shared resources the resources has time varying capacities (i.e $B_{rt}$ is the units of resource $r$ available in period $t$). For each project there is $...
10
votes
5answers
1k views

How to implement a "generic" solver for scheduling problems?

I have been accepted for an internship for 6 months. The aim of this internship is to implement a "generic" solver for scheduling/production planning problems. This solver will bill a small prototype ...
9
votes
1answer
407 views

Integrating genetic algorithm (or other heuristic methods) with CPLEX

[Topic to discuss GA and CPLEX] I've seen some papers trying to integrate genetic algorithm with CPLEX, such as here and here. Although they integrated both, it is done in 2 different steps; that ...
6
votes
2answers
270 views

A heuristic approach to solve a MILP problem?

I have the following optimization problem which is a MILP. I can solve it with a MILP solver. This one I posted here Is there a heuristic approach to the MILP problem? Since I have an additional but ...
8
votes
2answers
441 views

Is there a greedy heuristic approach to the MILP problem?

I have the following optimization problem which is an MILP. I can solve it with an MILP solver. \begin{alignat}{1}\max_{x_n,t}\,&\quad t\quad\\\text{s.t.}&\quad\sum_{n=1}^{N} x_n \,&= M\\...
9
votes
1answer
183 views

Rules of thumb for using classic methods (e.g. branch and bound) vs. meta-heuristics (G.A, S.A, etc..) for non-convex problems?

Are there any rules of thumb for when to use classical methods like branch and bound, branch and cut, etc...for non-convex problems, vs using meta-heuristic methods like genetic algorithms, ...
14
votes
4answers
539 views

Online Education for OR and Developing Decision Support Systems

I am looking for educational programmes which can be conducted online, such as full MSc., degree certificates, postgraduate courses/modules, MOOCs. Topics I am looking for are on advanced ...
13
votes
1answer
239 views

In Local Search, which reheating techniques have a good track record?

Given a fast-stepping Local Search (such as Simulated Annealing or Late Acceptance), which reheating approach is proven to work well? Generally speaking, reheating works like this: if [a condition is ...
7
votes
1answer
142 views

How to interpret the random solution pick by Lévy flight on cuckoo search

I am working on an implementation of Cuckoo Search for a set covering problem. After reading some papers I cannot understand how choosing a random solution (new cuckoo) works. What I see is that ...
11
votes
4answers
447 views

Good resources for solving techniques (Metaheuristics, MILP, CP etc)

I want some resources (tutorials, online courses, lecture notes, articles, books, etc.) to learn the different techniques to solve OR problems (metaheuristics, CP, MILP, etc). It would be better if ...
18
votes
8answers
1k views

Are metaheuristics ever practical for continuous optimization?

All of the applications of metaheuristics that I can think of are for discrete optimization (usually combinatorial optimization) problems. Are metaheuristics ever practical tools for continuous ...
10
votes
2answers
224 views

Parallelization of an existing Adaptive Large Neighbourhood Search Heuristic

I am solving (or say, trying to find good solutions for) an arbitrary combinatorial optimization problem, think of it as a Vehicle Routing Problem with a bunch of side constraints that are not ...
18
votes
1answer
289 views

Combinatorial Optimization: Metaheuristics, CP, IP -- "versus" or "and"?

"Recently" someone asked on Twitter whether "people still use genetic algorithms for integer programs". The "majority answer", i.e., 1 out of 1, was: "Yes" . So, my follow-up question is: With all ...