Questions tagged [metaheuristics]
Questions on general heuristic strategies that can be instantiated for a specific problem to obtain a heuristic.
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Objective function for employee assignation problem solved with simulated annealing
Imagine you have a total number of employees assigned to a task. Each task requires N quantity of employees for it to be 100% efficient, something like this:
Each employee is assigned to a task in ...
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How can I use a local search meta heuristic after completing construction heuristic?
I'm investigating how I can combine a construction heuristic and a local search metaheuristic to quickly solve Capacitated Split Delivery Veichle Routing Problem (CSDVRP). The construction heuristic ...
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Construction heuristic for SDCVRP
I'm not sure how I should formulate this question as precisely as possible but at the same time retaining as much specific information as possible but I'll have a go.
I have implemented a (Split ...
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Can I formulate a green vehicle routing problem with pyomo model then solve it with metaheuristics algorithms e.g. GA,HS rather than pyomo solver?
I want to use pyomo to formulate MILP problems in python such as Green Vehicle Routing Problem and others but use metaheuristics algorithms (GA, Harmony search, etc.) to solve those problems instead ...
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Book to learn metaheuristics
I want to learn about metaheuristics and start building one to solve combinatorial optimization which is pretty hard to solve. I am looking for book recommendation or any learning experience to learn ...
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How can we choose the right weight to solve multi-objective problem using weighted sum method?
I have a multi-objective problem with three objectives F1, F2, and F3. the problem was formulated as a weighted sum. Now I didn't know how I can choose the right weight for my problem
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Verifying optimality of heuristic solutions
Suppose that we have an mixed-integer linear optimization problem and we obtain a solution using a heuristic. How can one check 1) whether this solution is optimal and 2) how difficult is it to do so?
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Python vs. compiled languages in OR research using metaheuristics
In many articles that use metaheuristics to solve optimization problems, the programming language of choice is C++. For example, the following two articles present state-of-the-art metaheuristics to ...
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Metaheuristics vs Column generation for VRP
I am solving a vrp and its variants (pick up drop off, milk-run problem) using genetic algorithms. The issue that I am getting with the genetic algorithm is the randomness associated with the ...
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How to build a mathematical model to describe a problem related to ACO?
Suppose there are $n$ tasks assigned to $n$ workers, and each worker can be assigned only one task. Each worker can complete any one of the tasks, but the time spent varies. Use the ant colony ...
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When to use Tabu Search or Genetic Algorithms and when not?
Are there any rules of thumb about when to implement which? For example, I am trying to solve OR scheduling problems. I see that majority of people have implemented Genetic Algorithms. However, more ...
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Does this game that I invented correspond to a valid optimization problem?
Recently, I thought of the following "game" that I would like to frame as an optimization problem:
Assume there are five baskets. The first basket has five discrete objects (e.g., apples), ...
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Question re Tabu Search
I am working through the Udemy course "Optimizing Travelling Salesman and Vehicle Routing Problems".
A part of the course is looking at Tabu search as a solution to the vehicle routing ...
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Are Metaheuristics and Evolutionary Algorithms the "Gold Standard" for the Traveling Salesman Problem?
Are Metaheuristics and Evolutionary Algorithms the "Gold Standard" for the Traveling Salesman Problem?
I am interested in learning more about how we have been able to solve the (famous) ...
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Are there hybrid metaheuristic-solvers to solve combinatorial optimization problems?
I have a problem which is formulating a linear program. To solve large instances I implement a metaheuristic to solve my problem. In my problem, I have two objective functions.
With my linear program, ...
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Hybrid metaheuristic and linear program?
I have a Linear program (LP) that can solve problem X with two objective functions a and b, I use the weighted sum method. I use Gurobi solver when I optimize the objective alone, the problem takes a ...
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Drawbacks of Roulette Wheel selection mechanism
I am implementing the ALNS method with the selection mechanism which is the roulette wheel. But I still have a question about the disadvantages of this selection mechanism. I have searched in the ...
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How to say to Gurobi solver with Python API to start from a given solution?
I have a binary linear program, where all my variables are binary. So, I have implemented the problem on python with Gurobi solver. I have implemented also a heuristic to find a near-optimal solution.
...
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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 ...
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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 ...
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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 ...
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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.
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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: ...
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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 ...
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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?
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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 ...
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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 ...
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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,...
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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 ...
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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 ...
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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 ...
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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}^...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 $...
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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-...
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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 ...
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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.
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How to represent time windows as a constraint in a vehicle routing problem?
I am trying to solve a vehicle routing problem using Tabu search. I have successfully completed implementing the constraints for CVRP by giving penalties to in the objective function. How do I ...
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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).
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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 ...
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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 ...
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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 ...
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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 ...
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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 $...
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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 ...
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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 ...
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