Cuckoo Search Algorithm
This algorithm is an optimization algorithm that is inspired by the reproduction behavior of the cuckoo bird species. It is designed to find the global optimum for a given objective function with several constraints. The algorithm is based on the principle of randomization and is a derivative-free optimization algorithm. The algorithm operates on a population of candidate solutions, which are referred to as nests, and uses a stochastic algorithm to explore the solution space. The algorithm involves the random selection of a cuckoo's nest as a starting point, followed by a stochastic optimization process to search for a better solution.
Description
The Python code provided implements the cuckoo search algorithm to find the optimal path in a given graph. The code uses the following Python packages:
- random: This is a built-in Python package that is used to generate random numbers.
- networkx: This is a Python package used to work with graphs and networks. It is used to represent the graph and perform graph operations.
- numpy: This is a Python package used for scientific computing. It is used for numerical calculations.
- math: This is a built-in Python package that provides mathematical functions.
- datetime: This is a built-in Python package that is used to work with dates and times.
- pandas: This is a Python package used for data manipulation and analysis. It is used to store the test results. The code contains two classes: Cuckoo and CuckooSearch.
Class Cuckoo
This class represents a cuckoo. It has the following attributes:
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path: This is a list that represents the path that the cuckoo takes in the graph.
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G: This is a graph that represents the environment in which the cuckoo is operating.
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nodes: This is a list of nodes in the graph.
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eps: This is a small number used to avoid division by zero.
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fitness: This is the fitness value of the cuckoo. It is calculated using the calculate_fitness method. The Cuckoo class has the following methods:
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calculate_fitness: This method calculates the fitness value of the cuckoo. It computes the total distance of the path and raises it to the power of 2. This is done to avoid negative fitness values. The method returns the fitness value.
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generate_new_path: This method generates a new path for the cuckoo by performing a random walk in the graph. The method returns the new path.
Class CuckooSearch
This class represents the cuckoo search algorithm. It has the following attributes:
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G: This is a graph that represents the environment in which the cuckoos are operating.
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nodes: This is a list of nodes in the graph.
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num_cuckoos: This is the number of cuckoos in the population.
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max_iterations: This is the maximum number of iterations the algorithm will perform.
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beta: This is a parameter that controls the step size in the algorithm.
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cuckoos: This is a list of Cuckoo objects that represent the cuckoos in the population.
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test_results: This is a list that stores the test results.
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test_cases: This is the number of test cases performed. The CuckooSearch class has the following methods:
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levy_flight: This method generates a step size for the cuckoo. It is a random variable drawn from a Levy distribution. The method returns the step size.
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optimize: This method performs the optimization process. It iterates over the cuckoos in the population, generates a new path for each cuckoo, and evaluates its fitness. The cuckoo with the best fitness is stored as the current best solution. The method continues to iterate until a stopping criterion is met, such as reaching a maximum number of iterations or achieving a desired level of fitness. Once the optimization process is complete, the method returns the best solution found.