Matlab实现灰色预测的示例代码_C 语言

X0=[15 16.1 17.3 18.4 18.7 19.1 19.9 21.3 22.5];
t=1:9;    % 原始数据自变量范围
pt=10:12; % 预测数据自变量范围

X1=cumsum(X0);                    % 累加生成趋势明显新序列
Z=X1(1:end-1)+diff(X1)./2;        % 均值，即(X1(1:end-1)+X1(2:end))./2
a_u=polyfit(-Z,X0(2:end),1);      % a_u=(B'*B)\B'*Y,B=[-Z,ones]
a=a_u(1);u=a_u(2);
P=(X1(1)-u/a)./exp(a.*([t,pt]-1))+u/a; % 求X1拟合值
P=[P(1),diff(P)];                      % X1逐项做差求预测值

% 绘图
plot([t,pt],P,'*-');
hold on
plot(t,X0,'s-')  
legend('预测值','真实值');

X0=[15 16.1 17.3 18.4 18.7 19.1 19.9 21.3 22.5];
t=1:9;    % 原始数据自变量范围
pt=10:12; % 预测数据自变量范围

X1=cumsum(X0);                    % 累加生成趋势明显新序列
Z=X1(1:end-1)+diff(X1)./2;        % 均值，即(X1(1:end-1)+X1(2:end))./2
a_u=polyfit(-Z,X0(2:end),1);      % a_u=(B'*B)\B'*Y,B=[-Z,ones]
a=a_u(1);u=a_u(2);
P=(X1(1)-u/a)./exp(a.*([t,pt]-1))+u/a; % 求X1拟合值
P=[P(1),diff(P)];                      % X1逐项做差求预测值

% 绘图
plot([t,pt],P,'s-','Color',[82,124,179]./255,'MarkerFaceColor',[82,124,179]./255,...
    'MarkerEdgeColor',[1,1,1],'LineWidth',2,'MarkerSize',16)  
hold on
plot(t,X0,'d-.','Color',[169,64,71]./255,'MarkerFaceColor',[169,64,71]./255,...
    'MarkerEdgeColor',[1,1,1],'LineWidth',2,'MarkerSize',16)  

% 增添图例
lgd=legend('fitting result','original data');
lgd.Location='best';
lgd.FontSize=16;

% 坐标区域修饰
ax=gca;grid on;box off
ax.LineWidth=2;
ax.Color=[249,250,245]./255;
ax.XMinorTick='on';
ax.YMinorTick='on';
ax.GridLineStyle='-.';
ax.XColor=[1,1,1].*.2;
ax.YColor=[1,1,1].*.2;
ax.FontName='Cambria';
ax.FontSize=14;