genetic.py

import pandas as pd
import random


def selection(population,Np):
	df  = pd.DataFrame(population,index = ['Rating','Genome'])
	df = df.transpose()
	df.index.name = 'Individual'
	#print(df)

	#sort genomes on basis of genome ratings
	df = df.sort_values(by='Rating',ascending = False)
	#print('sorted')
	#print(df)

	#select the genomes of top Np% genomes from dataframe on basis of ratings,
	Np_num = int((Np/100) * len(df)) 
	#print(Np_num)
	top_Np = df.iloc[:Np_num,1]

	#print('Individuals selected for next generation')
	#print(top_Np)

	#Next we will generate a mating pool i.e make pairs of parents for combining
	no_of_pairs = int(len(top_Np)/2)
	mating_pool = []
	for i in range(0,no_of_pairs,2):
		mating_pool.append( [ top_Np[top_Np.index[i]],top_Np[top_Np.index[i+1]] ] )


	
	
	return mating_pool
	
def crossover(mating_pool):
	new_generation = []
	for pair in mating_pool:
		#print(pair)
		parent1 = pair[0]
		parent2 = pair[1]
		#print('parent 1: ',parent1)
		#print('parent 2: ',parent2)

		#we consider gene segments of length 4 bits, and perform crossover
		#operations between them exchanging the bits patterns i.e say
		# we had two genes 1100 and 0011,we split it at the at some random 
		# point k  = 2, and exchnage the bits preceding and following,
		#so after crossover it would look like 1111 and 0000

		offspring1 = ''
		offspring2 = ''

		for i in range(0,len(parent1),4):
			gene1 = parent1[i:i+4]
			gene2 = parent2[i:i+4]
			#print(gene1)
			#print(gene2)
			#print('-----')

			k  = random.randrange(0,4)
			#print('k:',k)
			sub_gene_1_1 = gene1[0:k]
			sub_gene_1_2 = gene1[k:]
			sub_gene_2_1 = gene2[0:k]
			sub_gene_2_2 = gene2[k:]

			new_gene_1 = sub_gene_1_1 + sub_gene_2_2
			new_gene_2 = sub_gene_2_1 + sub_gene_1_2

			#print('####')
			#print('new gene1: ',new_gene_1)
			#print('new gene2: ',new_gene_2)
			#print('')

			offspring1 = offspring1 + new_gene_1
			offspring2 = offspring2 + new_gene_2

		new_generation.append(offspring1)
		new_generation.append(offspring2)
	return new_generation

		#print('new offspring1: ',offspring1)
		#print('new offspring2: ',offspring2)




if __name__ == '__main__':
	parent1 = '1111000001011000'
	parent2 = '1110101001011011'

	mating_pool =[[parent1,parent2]]

	new_generation = crossover(mating_pool)
	print(new_generation)