GWO(灰狼优化)算法MATLAB源码逐行中文注解(转载)

以优化SVM算法的参数c和g为例,对GWO算法MATLAB源码进行了逐行中文注解。

tic % 计时器
%% 清空环境变量
close all
clear
clc
format compact
%% 数据提取
% 载入测试数据wine,其中包含的数据为classnumber = 3,wine:178*13的矩阵,wine_labes:178*1的列向量
load wine.mat
% 选定训练集和测试集
% 将第一类的1-30,第二类的60-95,第三类的131-153做为训练集
train_wine = [wine(1:30,:);wine(60:95,:);wine(131:153,:)];
% 相应的训练集的标签也要分离出来
train_wine_labels = [wine_labels(1:30);wine_labels(60:95);wine_labels(131:153)];
% 将第一类的31-59,第二类的96-130,第三类的154-178做为测试集
test_wine = [wine(31:59,:);wine(96:130,:);wine(154:178,:)];
% 相应的测试集的标签也要分离出来
test_wine_labels = [wine_labels(31:59);wine_labels(96:130);wine_labels(154:178)];
%% 数据预处理
% 数据预处理,将训练集和测试集归一化到[0,1]区间
[mtrain,ntrain] = size(train_wine);
[mtest,ntest] = size(test_wine); dataset = [train_wine;test_wine];
% mapminmax为MATLAB自带的归一化函数
[dataset_scale,ps] = mapminmax(dataset',0,1);
dataset_scale = dataset_scale'; train_wine = dataset_scale(1:mtrain,:);
test_wine = dataset_scale( (mtrain+1):(mtrain+mtest),: );
%% 利用灰狼算法选择最佳的SVM参数c和g
SearchAgents_no=10; % 狼群数量,Number of search agents
Max_iteration=10; % 最大迭代次数,Maximum numbef of iterations
dim=2; % 此例需要优化两个参数c和g,number of your variables
lb=[0.01,0.01]; % 参数取值下界
ub=[100,100]; % 参数取值上界
% v = 5; % SVM Cross Validation参数,默认为5 % initialize alpha, beta, and delta_pos
Alpha_pos=zeros(1,dim); % 初始化Alpha狼的位置
Alpha_score=inf; % 初始化Alpha狼的目标函数值,change this to -inf for maximization problems Beta_pos=zeros(1,dim); % 初始化Beta狼的位置
Beta_score=inf; % 初始化Beta狼的目标函数值,change this to -inf for maximization problems Delta_pos=zeros(1,dim); % 初始化Delta狼的位置
Delta_score=inf; % 初始化Delta狼的目标函数值,change this to -inf for maximization problems %Initialize the positions of search agents
Positions=initialization(SearchAgents_no,dim,ub,lb); Convergence_curve=zeros(1,Max_iteration); l=0; % Loop counter循环计数器 % Main loop主循环
while l<Max_iteration % 对迭代次数循环
for i=1:size(Positions,1) % 遍历每个狼 % Return back the search agents that go beyond the boundaries of the search space
% 若搜索位置超过了搜索空间,需要重新回到搜索空间
Flag4ub=Positions(i,:)>ub;
Flag4lb=Positions(i,:)<lb;
% 若狼的位置在最大值和最小值之间,则位置不需要调整,若超出最大值,最回到最大值边界;
% 若超出最小值,最回答最小值边界
Positions(i,:)=(Positions(i,:).*(~(Flag4ub+Flag4lb)))+ub.*Flag4ub+lb.*Flag4lb; % ~表示取反 % 计算适应度函数值
cmd = [' -c ',num2str(Positions(i,1)),' -g ',num2str(Positions(i,2))];
model=svmtrain(train_wine_labels,train_wine,cmd); % SVM模型训练
[~,fitness]=svmpredict(test_wine_labels,test_wine,model); % SVM模型预测及其精度
fitness=100-fitness(1); % 以错误率最小化为目标 % Update Alpha, Beta, and Delta
if fitness<Alpha_score % 如果目标函数值小于Alpha狼的目标函数值
Alpha_score=fitness; % 则将Alpha狼的目标函数值更新为最优目标函数值,Update alpha
Alpha_pos=Positions(i,:); % 同时将Alpha狼的位置更新为最优位置
end if fitness>Alpha_score && fitness<Beta_score % 如果目标函数值介于于Alpha狼和Beta狼的目标函数值之间
Beta_score=fitness; % 则将Beta狼的目标函数值更新为最优目标函数值,Update beta
Beta_pos=Positions(i,:); % 同时更新Beta狼的位置
end if fitness>Alpha_score && fitness>Beta_score && fitness<Delta_score % 如果目标函数值介于于Beta狼和Delta狼的目标函数值之间
Delta_score=fitness; % 则将Delta狼的目标函数值更新为最优目标函数值,Update delta
Delta_pos=Positions(i,:); % 同时更新Delta狼的位置
end
end a=2-l*((2)/Max_iteration); % 对每一次迭代,计算相应的a值,a decreases linearly fron 2 to 0 % Update the Position of search agents including omegas
for i=1:size(Positions,1) % 遍历每个狼
for j=1:size(Positions,2) % 遍历每个维度 % 包围猎物,位置更新 r1=rand(); % r1 is a random number in [0,1]
r2=rand(); % r2 is a random number in [0,1] A1=2*a*r1-a; % 计算系数A,Equation (3.3)
C1=2*r2; % 计算系数C,Equation (3.4) % Alpha狼位置更新
D_alpha=abs(C1*Alpha_pos(j)-Positions(i,j)); % Equation (3.5)-part 1
X1=Alpha_pos(j)-A1*D_alpha; % Equation (3.6)-part 1 r1=rand();
r2=rand(); A2=2*a*r1-a; % 计算系数A,Equation (3.3)
C2=2*r2; % 计算系数C,Equation (3.4) % Beta狼位置更新
D_beta=abs(C2*Beta_pos(j)-Positions(i,j)); % Equation (3.5)-part 2
X2=Beta_pos(j)-A2*D_beta; % Equation (3.6)-part 2 r1=rand();
r2=rand(); A3=2*a*r1-a; % 计算系数A,Equation (3.3)
C3=2*r2; % 计算系数C,Equation (3.4) % Delta狼位置更新
D_delta=abs(C3*Delta_pos(j)-Positions(i,j)); % Equation (3.5)-part 3
X3=Delta_pos(j)-A3*D_delta; % Equation (3.5)-part 3 % 位置更新
Positions(i,j)=(X1+X2+X3)/3;% Equation (3.7) end
end
l=l+1;
Convergence_curve(l)=Alpha_score;
end
bestc=Alpha_pos(1,1);
bestg=Alpha_pos(1,2);
bestGWOaccuarcy=Alpha_score;
%% 打印参数选择结果
disp('打印选择结果');
str=sprintf('Best Cross Validation Accuracy = %g%%,Best c = %g,Best g = %g',bestGWOaccuarcy*100,bestc,bestg);
disp(str)
%% 利用最佳的参数进行SVM网络训练
cmd_gwosvm = ['-c ',num2str(bestc),' -g ',num2str(bestg)];
model_gwosvm = svmtrain(train_wine_labels,train_wine,cmd_gwosvm);
%% SVM网络预测
[predict_label,accuracy] = svmpredict(test_wine_labels,test_wine,model_gwosvm);
% 打印测试集分类准确率
total = length(test_wine_labels);
right = sum(predict_label == test_wine_labels);
disp('打印测试集分类准确率');
str = sprintf( 'Accuracy = %g%% (%d/%d)',accuracy(1),right,total);
disp(str);
%% 结果分析
% 测试集的实际分类和预测分类图
figure;
hold on;
plot(test_wine_labels,'o');
plot(predict_label,'r*');
xlabel('测试集样本','FontSize',12);
ylabel('类别标签','FontSize',12);
legend('实际测试集分类','预测测试集分类');
title('测试集的实际分类和预测分类图','FontSize',12);
grid on
snapnow
%% 显示程序运行时间
toc

  

% This function initialize the first population of search agents
function Positions=initialization(SearchAgents_no,dim,ub,lb) Boundary_no= size(ub,2); % numnber of boundaries % If the boundaries of all variables are equal and user enter a signle
% number for both ub and lb
if Boundary_no==1
Positions=rand(SearchAgents_no,dim).*(ub-lb)+lb;
end % If each variable has a different lb and ub
if Boundary_no>1
for i=1:dim
ub_i=ub(i);
lb_i=lb(i);
Positions(:,i)=rand(SearchAgents_no,1).*(ub_i-lb_i)+lb_i;
end
end

  

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作者:Genlovy_Hoo
来源:CSDN
原文:https://blog.csdn.net/u013337691/article/details/52468552
版权声明:本文为博主原创文章,转载请附上博文链接!

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