%%  清空环境变量
warning off             % 关闭报警信息
close all               % 关闭开启的图窗
clear                   % 清空变量
clc                     % 清空命令行

%%  导入数据（时间序列的单列数据）
result = xlsread('数据集.xlsx');

%%  数据分析
num_samples = length(result);  % 样本个数 
kim = 15;                      % 延时步长（kim个历史数据作为自变量）
zim =  1;                      % 跨zim个时间点进行预测

%%  构造数据集
for i = 1: num_samples - kim - zim + 1
    res(i, :) = [reshape(result(i: i + kim - 1), 1, kim), result(i + kim + zim - 1)];
end

%%  划分训练集和测试集
temp = 1: 1: 922;

P_train = res(temp(1: 700), 1: 15)';
T_train = res(temp(1: 700), 16)';
M = size(P_train, 2);

P_test = res(temp(701: end), 1: 15)';
T_test = res(temp(701: end), 16)';
N = size(P_test, 2);

%%  数据归一化
[p_train, ps_input] = mapminmax(P_train, 0, 1);
p_test = mapminmax('apply', P_test, ps_input);

[t_train, ps_output] = mapminmax(T_train, 0, 1);
t_test = mapminmax('apply', T_test, ps_output);

%%  转置以适应模型
p_train = p_train'; p_test = p_test';
t_train = t_train'; t_test = t_test';

%%  创建模型
c = 4.0;    % 惩罚因子
g = 0.8;    % 径向基函数参数
cmd = [' -t 2',' -c ',num2str(c),' -g ',num2str(g),' -s 3 -p 0.01'];
model = svmtrain(t_train, p_train, cmd);

%%  仿真预测
[t_sim1, error_1] = svmpredict(t_train, p_train, model);
[t_sim2, error_2] = svmpredict(t_test , p_test , model);

%%  数据反归一化
T_sim1 = mapminmax('reverse', t_sim1, ps_output);
T_sim2 = mapminmax('reverse', t_sim2, ps_output);

%%  均方根误差
error1 = sqrt(sum((T_sim1' - T_train).^2) ./ M);
error2 = sqrt(sum((T_sim2' - T_test ).^2) ./ N);

%%  绘图
figure
plot(1: M, T_train, 'r-', 1: M, T_sim1, 'b-', 'LineWidth', 1)
legend('真实值', '预测值')
xlabel('预测样本')
ylabel('预测结果')
string = {'训练集预测结果对比'; ['RMSE=' num2str(error1)]};
title(string)
xlim([1, M])
grid

figure
plot(1: N, T_test, 'r-', 1: N, T_sim2, 'b-', 'LineWidth', 1)
legend('真实值', '预测值')
xlabel('预测样本')
ylabel('预测结果')
string = {'测试集预测结果对比'; ['RMSE=' num2str(error2)]};
title(string)
xlim([1, N])
grid

%%  相关指标计算
% R2
R1 = 1 - norm(T_train - T_sim1')^2 / norm(T_train - mean(T_train))^2;
R2 = 1 - norm(T_test  - T_sim2')^2 / norm(T_test  - mean(T_test ))^2;

disp(['训练集数据的R2为：', num2str(R1)])
disp(['测试集数据的R2为：', num2str(R2)])

% MAE
mae1 = sum(abs(T_sim1' - T_train)) ./ M ;
mae2 = sum(abs(T_sim2' - T_test )) ./ N ;

disp(['训练集数据的MAE为：', num2str(mae1)])
disp(['测试集数据的MAE为：', num2str(mae2)])

% MBE
mbe1 = sum(T_sim1' - T_train) ./ M ;
mbe2 = sum(T_sim2' - T_test ) ./ N ;

disp(['训练集数据的MBE为：', num2str(mbe1)])
disp(['测试集数据的MBE为：', num2str(mbe2)])

%%  绘制散点图
sz = 25;
c = 'b';

figure
scatter(T_train, T_sim1, sz, c)
hold on
plot(xlim, ylim, '--k')
xlabel('训练集真实值');
ylabel('训练集预测值');
xlim([min(T_train) max(T_train)])
ylim([min(T_sim1) max(T_sim1)])
title('训练集预测值 vs. 训练集真实值')

figure
scatter(T_test, T_sim2, sz, c)
hold on
plot(xlim, ylim, '--k')
xlabel('测试集真实值');
ylabel('测试集预测值');
xlim([min(T_test) max(T_test)])
ylim([min(T_sim2) max(T_sim2)])
title('测试集预测值 vs. 测试集真实值')