Biomedical

Combining Genetic Algorithm with Local Search Method in Solving Optimization Problems



  Peer Reviewed

Abstract

This research is focused on evolutionary algorithms, with genetic and memetic algorithms discussed in more detail. A graph theory problem related to finding a minimal Hamiltonian cycle in a complete undirected graph (Travelling Salesman Problem—TSP) is considered. The implementations of two approximate algorithms for solving this problem, genetic and memetic, are presented. The main objective of this study is to determine the influence of the local search method versus the influence of the genetic crossover operator on the quality of the solutions generated by the memetic algorithm for the same input data. The results show that when the number of possible Hamiltonian cycles in a graph is increased, the memetic algorithm finds better solutions. The execution time of both algorithms is comparable. Also, the number of solutions that mutated during the execution of the genetic algorithm exceeds 50% of the total number of all solutions generated by the crossover operator. In the memetic algorithm, the number of solutions that mutate does not exceed 10% of the total number of all solutions generated by the crossover operator, summed with those of the local search method.

Key Questions about Genetic and Memetic Algorithms in Optimization

The article "Combining Genetic Algorithm with Local Search Method in Solving Optimization Problems" explores the integration of genetic algorithms (GAs) with local search techniques to address combinatorial optimization challenges, specifically focusing on the Traveling Salesman Problem (TSP). The study compares the performance of a genetic algorithm with a memetic algorithm—a hybrid approach that combines genetic algorithms with local search methods—in finding the minimal Hamiltonian cycle in a complete undirected graph. The results indicate that as the number of possible Hamiltonian cycles in a graph increases, the memetic algorithm tends to find better solutions. Additionally, the execution time of both algorithms is comparable. Notably, in the genetic algorithm, more than 50% of the solutions generated by the crossover operator undergo mutation, whereas in the memetic algorithm, the number of mutated solutions does not exceed 10% of the total solutions generated by the crossover operator, combined with those from the local search method. :contentReference[oaicite:4]{index=4}

1. How does the integration of genetic algorithms with local search methods impact the quality of solutions in combinatorial optimization problems?

The study demonstrates that combining genetic algorithms with local search methods, as in the memetic algorithm, enhances the quality of solutions for combinatorial optimization problems like the Traveling Salesman Problem. This integration allows for more effective exploration and exploitation of the solution space, leading to improved outcomes. :contentReference[oaicite:5]{index=5}

2. What are the comparative execution times of genetic and memetic algorithms in solving optimization problems?

The research indicates that the execution times of both genetic and memetic algorithms are comparable. This suggests that the additional computational effort required for the local search component in the memetic algorithm does not significantly increase the overall processing time compared to the genetic algorithm. :contentReference[oaicite:6]{index=6}

3. What is the role of mutation in the genetic algorithm compared to the memetic algorithm?

In the genetic algorithm, more than 50% of the solutions generated by the crossover operator undergo mutation. In contrast, the memetic algorithm exhibits a lower mutation rate, with mutated solutions not exceeding 10% of the total solutions generated by the crossover operator, combined with those from the local search method. This difference highlights the varying strategies employed by the two algorithms in exploring the solution space. :contentReference[oaicite:7]{index=7}