PSO

from cmath import sin
from random import randint, random

import numpy as np


class Particle:
    def __init__(self, pos, l, f):
        """
        pos : problem::individual
        """
        self.__position = pos
        self.__size = l
        self.fit = f
        self.evaluate()
        self.velocity = [[0 for i in range(l)] for j in range(l)]

        self._bestPosition = self.__position.copy()
        self._bestFitness = self._fitness

    def evaluate(self):
        self._fitness = self.fit(self.__position)

    @property
    def position(self):
        return self.__position

    @property
    def fitness(self):
        return self._fitness

    @property
    def best_position(self):
        return self._bestPosition

    @property
    def best_fitness(self):
        return self._bestFitness

    @position.setter
    def position(self, newPozition):
        self.__position = newPozition.copy()
        # automatic evaluation of particle's fitness
        self.evaluate()
        # automatic update of particle's memory
        if (self._fitness < self._bestFitness):
            self._bestPosition = self.__position
            self._bestFitness = self._fitness

class PSO:
    def __init__(self, size, f):
        self.__size = size
        self.fitness = f
        self.__pop = self.population(size)                                #!!!!
        self.__neighbours = self.select_neighbours(self.__pop, 20)
        self.w = 1.0
        self.c1 = 1.0
        self.c2 = 2.5

    def get_pop(self):
        return self.__pop

    def individual(self):
        m=[]
        for i in range(self.__size*2):
            m.append(list((np.random.permutation(self.__size)+1)))
        return m

    def population(self, num):
        '''Generates num individuals'''
        pop = []
        for i in range(num):
            pop.append(Particle(self.individual(), self.__size, self.fitness))
        return pop

    def select_neighbours(self, pop, size):
        if (size > len(pop)):
            size = len(pop)


        neighbors = []
        for i in range(len(pop)):
            localNeighbuor = []
            for j in range(size):
                x = randint(0, len(pop) - 1)
                while (x in localNeighbuor):
                    x = randint(0, len(pop) - 1)
                localNeighbuor.append(x)
            neighbors.append(localNeighbuor.copy())
        return neighbors

    def iteration(self, pop, f):
        best_neighbors = []

        for i in range(len(pop)):
            best_neighbors.append(self.__neighbours[i][0])
            for j in range(1, len(self.__neighbours[i])):
                if (pop[best_neighbors[i]].fitness > pop[self.__neighbours[i][j]].fitness):
                    best_neighbors[i] = self.__neighbours[i][j]

        for i in range(len(pop)):
            for j in range(len(pop[0].velocity)):
                new_velocity = self.w * pop[i].velocity
                new_velocity = new_velocity + self.c1 * random() * (pop[best_neighbors[i]].position[j] - pop[i].position[j])
                new_velocity = new_velocity + self.c2 * random() * (pop[i].best_position[j] - pop[i].position[j])
                pop[i].velocity[j] = new_velocity

        for i in range(len(pop)):
            new_position = []
            for j in range(len(pop[0].velocity)):
                new_position.append(pop[i].position[j] + pop[i].velocity[j])
            pop[i].position = new_position
        return pop