init.asv

遗传算法样例

function [ x q ] = Init(PopSize)
%UNTITLED1 Summary of this function goes here
%   Detailed explanation goes here
x = rand(PopSize, 3);
a = 0.05;
q(1) = 0.05;
for i=2:PopSize+1
    a = a*0.95;
    q(i) = q(i-1)+a;
end;
for i=2:PopSize+1   
    while x(i,1)<0 || x(i,2)<0 || x(i,3)<0 || power(x(i,1),2)+2*power(x(i,2),2)+3*power(x(i,3),2) > 1
        x(i,:) = rand(1,3); 
    end
end
%目标函数
function [Objective] = objective_function(PopSize, chromosome)

for i=2:PopSize+1
    x1 = chromosome(i,1);
    x2 = chromosome(i,2);
    x3 = chromosome(i,3);
    Objective(i,2) = sqrt(x1)+sqrt(x2)+sqrt(x3); 
end
for i=2:PopSize+1
    Objective(i,1) = max(Objective(i,:));
end
%评估函数
function evaluation(gen, PopSize, chromosome)

Objective = Objective_function(PopSize, chromosome);
if gen == 0
    Objective(1,1) = Objective(2,1);
    chromosome(1,:) = chromosome(2,:);
end

for i=1:PopSize
    label = 1;
    a = Objective(i,1);
    for j=i+1:PopSize+1
        if a < Objective(j,1)
            a = Objective(j,1);
            label = j;
        end
    end
    if lable ~= 1
        a = Objective(i,1)
    end
end

%选择函数
function selection(PopSize, chromosome)

for i=2:PopSize+1
    r = rand(1,1)*q(PopSize);
    for j=2:PopSize+1
        if r <= q(j)
            temp = chromosome(j,:);
            break;
        end
    end
    for i=2:PopSize+1
        chromosome(i,:) = temp(i,:);
    end
end

%交叉函数
function crossover(PopSize, P_Crossover, chromosome)

pop = PopSize/2;
for i=2:pop+1
    if rand() > P_Crossover
        continue;
    end
    j = round(rand()*PopSize);
    jj = round(rand()*PopSize);
    r = rand();
    x = r*chromosome(j,:)+(1-r)*chromosome(jj,:);
    y = r*chromosome(jj,:)+(1-r)*chromosome(j,:);
    if power(x(i,1),2)+2*power(x(i,2),2)+3*power(x(i,3),2) <= 1
        chromosome(j,:) = x;
    elseif power(y(i,1),2)+2*power(y(i,2),2)+3*power(y(i,3),2) <= 1
        chromosome(jj,:) = y;
    end
end

%变异函数
function mutation(PopSize, P_Mutation, chromosome)

INFTY = 10;
precision = 0.0001;
for i=2:PopSize+1
    if rand() > P_Mutation
        continue;
    end
    x = chromosome(i,:);
    for k=1:3
        if rand() < 0.5
            direction(k) = rand()*2-1;
        else
            direction(k) = 0;
        end
    end
    infty = rand()*INFTY;
    while infty > precision
        for j=1:3
            y(j) = x(j)+infty*direction(j);
        end
        if power(y(i,1),2)+2*power(y(i,2),2)+3*power(y(i,3),2) <= 1
            chromosome(i,:) = y;
            break;
        end
        infty = rand()*infty;
    end
end

%主函数
function Main(PopSize, GEN, P_Crossover, P_Mutation)

[x q] = Init(PopSize);
evaluation(0, PopSize, x);
for i=1:GEN
    selection(PopSize, x);
    crossover(PopSize, P_Crossover, x);
    mutation(PopSize, P_Mutation, x);
    evaluation(i, PopSize, x);
end