Questions tagged [metaheuristics]
Questions on general heuristic strategies that can be instantiated for a specific problem to obtain a heuristic.
72
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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,...
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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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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 ...
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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 ...
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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 ...
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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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11
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4
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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 ...
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3
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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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10
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3
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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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2
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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 ...
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5
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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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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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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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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, ...
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8
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2
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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\\...
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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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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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7
votes
2
answers
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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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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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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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2
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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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7
votes
1
answer
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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 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 ...
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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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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 ...
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2
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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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1
answer
286
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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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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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votes
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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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4
votes
1
answer
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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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4
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1
answer
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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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4
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0
answers
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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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3
answers
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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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3
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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 ...
3
votes
1
answer
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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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3
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1
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Optimization challenges (currently active or soon to begin)
I am looking for an optimization challenge for an intern (such as ROADEF Challenge, Gecco competitions, or CEC competitions) active during summer 2023 (ideally July - September). Longer competitions ...
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0
answers
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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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0
answers
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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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3
answers
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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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2
votes
2
answers
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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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3
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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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1
answer
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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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votes
1
answer
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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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answer
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Container Loading Problem
I'd like to optimize the loading problem in first-mile delivery that maximize the occupancy of the truck. The main question to be answered is this: with the given truck, would this list of items fit ...
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votes
1
answer
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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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2
votes
1
answer
121
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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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votes
1
answer
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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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votes
1
answer
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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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0
answers
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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 ...
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0
answers
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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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