% Initialization %初始化
clear
clc
n = 50; % "鸟群大小
bird_setp = 50; % 最大迭代次数
dim = 3; % 维度
c2 =1.2; % 加速因子，为正
c1 = 0.12; % 加速因子
w =0.9; % 惯性因子
fitness=zeros(n,bird_setp); %目标函数
R1 = rand(dim,n); %[0,1]的随机数组
R2 = rand(dim,n); %随机数
current_fitness =zeros(n,1); %局部最优
%-------------------------%
% 初始化种群、速度和位置
%--------------------------%
current_position = 10*(rand(dim, n)-.5);
velocity = .3*randn(dim, n) ;
pbest = current_position ;
%-----------------------%
% 评价初始种群 %
%--------------------- -%
for i = 1:n
current_fitness(i) = fs(current_position(:,i),dim); % 计算目标函数
end
local_best_fitness = current_fitness ; %局部最优目标值
[global_best_fitness,g] = min(local_best_fitness) ; %全局最优目标值
for i=1:n
gbest(:,i) = pbest(:,g) ; % 全局最优位置和局部最优位置的关系
end
velocity = w *velocity + c1*(R1.*(pbest-current_position)) + c2*(R2.*(gbest-current_position));
% 速度的变化公式
current_position = current_position + velocity ; %位置的变化公式
%% Main Loop
iter = 0 ; % Iterations counter 迭代次数的计算统计
while ( iter < bird_setp )
iter = iter + 1;
for i = 1:n,
current_fitness(i) = fs(current_position(:,i),dim) ; %利用Live_fn函数求当前最优目标值
end
for i = 1 : n
if current_fitness(i) < local_best_fitness(i) %若当前局部最优目标值小于上一次的目标值
local_best_fitness(i) = current_fitness(i); %局部最优值改变为当前值
pbest(:,i) = current_position(:,i) ; %局部最优位置改变为当前位置
end
end
[current_global_best_fitness,g] = min(local_best_fitness); %全局最优目标值等于局部最优目标值中的最小值
if current_global_best_fitness < global_best_fitness %将当前全局最优目标值与上一次目标值进行比较
global_best_fitness = current_global_best_fitness; %全局最优目标值等于当前的目标值
for i=1:n
gbest(:,i) = pbest(:,g); %全局最优位置改变
end
end
velocity = w *velocity + c1*(R1.*(pbest-current_position)) + c2*(R2.*(gbest-current_position));
current_position = current_position + velocity;
x=current_position(1,:); %最优位置的横坐标
y=current_position(2,:); %最优位置的纵坐标
z=current_position(3,:);
%clf %清除上一次图形
% plot(x,y,'h')
% hold on
% plot(x, y,'r:'); %将(x,y)的散点图画出
plot3(x,y,z,'h')
% hold on
% plot3(x,y,z,'m:')
axis([-5 5 -5 5 -5 5]);
pause(.2) %暂停程序执行，进入下一次迭代
end
[Jbest_min,I] = min(current_fitness) %全局最优目标值，及下标
X=current_position(:,I) %全局最优位置
%
