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"""! |
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@brief Cluster analysis algorithm: Genetic clustering algorithm (GA). |
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@authors Aleksey Kukushkin ([email protected]) |
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@date 2014-2017 |
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@copyright GNU Public License |
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@cond GNU_PUBLIC_LICENSE |
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PyClustering is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation, either version 3 of the License, or |
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(at your option) any later version. |
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PyClustering is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program. If not, see <http://www.gnu.org/licenses/>. |
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@endcond |
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""" |
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import numpy as np; |
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import math; |
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from pyclustering.cluster.ga_maths import ga_math; |
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class genetic_algorithm: |
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"""! |
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@brief Class represents Genetic clustering algorithm. |
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@details The searching capability of genetic algorithms is exploited in order to search for appropriate cluster centres. |
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""" |
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def __init__(self, data, count_clusters, chromosome_count, population_count, count_mutation_gens=2, |
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coeff_mutation_count=0.25, select_coeff=1.0): |
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"""! |
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@brief Initialize genetic clustering algorithm for cluster analysis. |
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@param[in] data (numpy.array|list): Input data for clustering that is represented by two dimensional array where each row is a point, |
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for example, [[0.0, 2.1], [0.1, 2.0], [-0.2, 2.4]]. |
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@param[in] count_clusters (uint): Amount of clusters that should be allocated in the data. |
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@param[in] chromosome_count (uint): Amount of chromosomes in each population. |
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@param[in] population_count (uint): Amount of populations. |
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@param[in] count_mutation_gens (uint): Amount of genes in chromosome that is mutated on each step. |
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@param[in] coeff_mutation_count (float): Percent of chromosomes for mutation, destributed in range (0, 1] and |
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thus amount of chromosomes is defined as follows: 'chromosome_count' * 'coeff_mutation_count'. |
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@param[in] select_coeff (float): Exponential coefficient for selection procedure that is used as follows: math.exp(1 + fitness(chromosome) * select_coeff). |
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""" |
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# Initialize random |
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np.random.seed() |
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# Clustering data |
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if type(data) is list: |
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self.data = np.array(data) |
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else: |
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self.data = data |
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# Count clusters |
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self.count_clusters = count_clusters |
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# Home many chromosome in population |
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self.chromosome_count = chromosome_count |
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# How many populations |
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self.population_count = population_count |
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# Count mutation genes |
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self.count_mutation_gens = count_mutation_gens |
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# Crossover rate |
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self.crossover_rate = 1.0 |
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# Count of chromosome for mutation (range [0, 1]) |
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self.coeff_mutation_count = coeff_mutation_count |
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# Exponential coeff for selection |
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self.select_coeff = select_coeff |
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def process(self): |
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"""! |
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@brief Perform clustering procedure in line with rule of genetic clustering algorithm. |
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@see get_clusters() |
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""" |
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# Initialize population |
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chromosomes = self._init_population(self.count_clusters, len(self.data), self.chromosome_count) |
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# Initialize the Best solution |
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best_chromosome, best_ff = self._get_best_chromosome(chromosomes, self.data, self.count_clusters) |
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# Next population |
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for _ in range(self.population_count): |
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# Select |
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chromosomes = self._select(chromosomes, self.data, self.count_clusters, self.select_coeff) |
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# Crossover |
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self._crossover(chromosomes) |
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# Mutation |
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self._mutation(chromosomes, self.count_clusters, self.count_mutation_gens, self.coeff_mutation_count) |
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# Update the Best Solution |
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new_best_chromosome, new_best_ff = self._get_best_chromosome(chromosomes, self.data, self.count_clusters) |
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# Get best chromosome |
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if new_best_ff < best_ff: |
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best_ff = new_best_ff |
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best_chromosome = new_best_chromosome |
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return best_chromosome, best_ff |
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View Code Duplication |
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def get_clusters(self): |
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"""! |
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@brief Returns list of allocated clusters, each cluster contains indexes of objects from the data. |
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@return (list) List of allocated clusters. |
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@see process() |
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""" |
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raise NameError("Implementation is require."); |
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@staticmethod |
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def _select(chromosomes, data, count_clusters, select_coeff): |
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"""! |
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@brief Performs selection procedure where new chromosomes are calculated. |
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@param[in] chromosomes (numpy.array): Chromosomes |
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""" |
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# Calc centers |
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View Code Duplication |
centres = ga_math.get_centres(chromosomes, data, count_clusters) |
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# Calc fitness functions |
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fitness = genetic_algorithm._calc_fitness_function(centres, data, chromosomes) |
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for _idx in range(len(fitness)): |
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fitness[_idx] = math.exp(1 + fitness[_idx] * select_coeff) |
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# Calc probability vector |
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probabilities = ga_math.calc_probability_vector(fitness) |
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# Select P chromosomes with probabilities |
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new_chromosomes = np.zeros(chromosomes.shape, dtype=np.int) |
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# Selecting |
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for _idx in range(len(chromosomes)): |
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new_chromosomes[_idx] = chromosomes[ga_math.get_uniform(probabilities)] |
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return new_chromosomes |
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@staticmethod |
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def _crossover(chromosomes): |
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"""! |
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@brief Crossover procedure. |
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""" |
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# Get pairs to Crossover |
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pairs_to_crossover = np.array(range(len(chromosomes))) |
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# Set random pairs |
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np.random.shuffle(pairs_to_crossover) |
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# Index offset ( pairs_to_crossover split into 2 parts : [V1, V2, .. | P1, P2, ...] crossover between V<->P) |
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offset_in_pair = int(len(pairs_to_crossover) / 2) |
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# For each pair |
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for _idx in range(offset_in_pair): |
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# Generate random mask for crossover |
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crossover_mask = genetic_algorithm._get_crossover_mask(len(chromosomes[_idx])) |
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# Crossover a pair |
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genetic_algorithm._crossover_a_pair(chromosomes[pairs_to_crossover[_idx]], |
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chromosomes[pairs_to_crossover[_idx + offset_in_pair]], |
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crossover_mask) |
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@staticmethod |
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def _mutation(chromosomes, count_clusters, count_gen_for_mutation, coeff_mutation_count): |
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"""! |
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@brief Mutation procedure. |
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""" |
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# Count gens in Chromosome |
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count_gens = len(chromosomes[0]) |
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# Get random chromosomes for mutation |
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random_idx_chromosomes = np.array(range(len(chromosomes))) |
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np.random.shuffle(random_idx_chromosomes) |
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# |
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for _idx_chromosome in range(int(len(random_idx_chromosomes) * coeff_mutation_count)): |
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# |
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for _ in range(count_gen_for_mutation): |
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# Get random gen |
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gen_num = np.random.randint(count_gens) |
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# Set random cluster |
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chromosomes[random_idx_chromosomes[_idx_chromosome]][gen_num] = np.random.randint(count_clusters) |
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@staticmethod |
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def _crossover_a_pair(chromosome_1, chromosome_2, mask): |
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"""! |
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@brief Crossovers a pair of chromosomes. |
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@param[in] chromosome_1 (numpy.array): The first chromosome for crossover. |
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@param[in] chromosome_2 (numpy.array): The second chromosome for crossover. |
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@param[in] mask (numpy.array): Crossover mask that defines which genes should be swapped. |
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""" |
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for _idx in range(len(chromosome_1)): |
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if mask[_idx] == 1: |
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# Swap values |
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chromosome_1[_idx], chromosome_2[_idx] = chromosome_2[_idx], chromosome_1[_idx] |
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@staticmethod |
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def _get_crossover_mask(mask_length): |
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"""! |
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@brief Crossover mask to crossover a pair of chromosomes. |
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@param[in] mask_length (uint): Length of the mask. |
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""" |
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# Initialize mask |
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mask = np.zeros(mask_length) |
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# Set a half of array to 1 |
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mask[:int(int(mask_length) / 6)] = 1 |
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# Random shuffle |
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np.random.shuffle(mask) |
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return mask |
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@staticmethod |
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def _init_population(count_clusters, count_data, chromosome_count): |
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"""! |
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@brief Returns first population as a uniform random choice. |
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@param[in] count_clusters (uint): |
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@param[in] count_data (uint): |
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@param[in] chromosome_count (uint): |
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""" |
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population = np.random.randint(count_clusters, size=(chromosome_count, count_data)) |
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return population |
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@staticmethod |
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def _get_best_chromosome(chromosomes, data, count_clusters): |
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"""! |
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@brief |
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""" |
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# Calc centers |
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centres = ga_math.get_centres(chromosomes, data, count_clusters) |
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# Calc Fitness functions |
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fitness_function = genetic_algorithm._calc_fitness_function(centres, data, chromosomes) |
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# Index of the best chromosome |
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best_chromosome_idx = fitness_function.argmin() |
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# Get chromosome with the best fitness function |
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return chromosomes[best_chromosome_idx], fitness_function[best_chromosome_idx] |
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@staticmethod |
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def _calc_fitness_function(centres, data, chromosomes): |
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"""! |
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@brief |
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""" |
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# Get count of chromosomes and clusters |
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count_chromosome = len(chromosomes) |
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# Initialize fitness function values |
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fitness_function = np.zeros(count_chromosome) |
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# Calc fitness function for each chromosome |
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for _idx_chromosome in range(count_chromosome): |
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# Get centers for a selected chromosome |
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centres_data = np.zeros(data.shape) |
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# Fill data centres |
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for _idx in range(len(data)): |
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centres_data[_idx] = centres[_idx_chromosome][chromosomes[_idx_chromosome][_idx]] |
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# Get City Block distance for a chromosome |
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fitness_function[_idx_chromosome] += np.sum(abs(data - centres_data)) |
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return fitness_function |
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This can be caused by one of the following:
1. Missing Dependencies
This error could indicate a configuration issue of Pylint. Make sure that your libraries are available by adding the necessary commands.
2. Missing __init__.py files
This error could also result from missing
__init__.py
files in your module folders. Make sure that you place one file in each sub-folder.