南京邮电大学数学实验MATLAB2023综合练习1参考

x=[1:39] y=[185035,188351,191112,193953,196086,199074,200654,20334,205257,207081,208584,214243,215667,216587,217452,217836,218198,218571,218945,219296,219625,220040,220397,220721,220958,221289,221565,221804,221955,222130,222370,222582,222775,222976,223145,223332,223488,223605,223735]; a=[10000,2,0.1]; f=@(a,x)a(1)./(1+a(2)*exp(-a(3)*x)); [A,resnorm]=lsqcurvefit(f,a,x,y) t=39 while f(A,t+1)-f(A,t)>=1; t=t+1; end t f(A,t+1) t=1:50; plot(x,y,'b*',t,f(A,t+1),'k')这个是我自己搞得差错很多 % 输入数据 data = [185035,188351,191112,193953,196086,199074,200654,20334,205257,207081,208584,214243,215667,216587,217452,217836,218198,218571,218945,219296,219625,220040,220397,220721,220958,221289,221565,221804,221955,222130,222370,222582,222775,222976,223145,223332,223488,223605,223735]; x=1:length(data); f=@(a,x) a(1)./(1 + a(2)*exp(-a(3)*x)); ini=[max(data),2,0.1]; % 利用 lsqcurvefit 进行拟合 par=lsqcurvefit(f,ini,x,data); % 生成拟合曲线 fit=f(par, x); % 绘制原始数据和拟合曲线 figure; plot(x,data,'o-','DisplayName','实际数据'); hold on; plot(x,fit,'*-','DisplayName','拟合数据'); % 预测未来感染人数 f_days=1:30; % 预测未来30天 f_x=x(end) + f_days; p_data=f(par, f_x); % 绘制预测未来感染人数曲线 plot(f_x,p_data,'x-','DisplayName','预测数据'); xlabel('日期'); ylabel('感染人数'); legend('show'); title('感染人数拟合与预测');这个是别人帮我搞的 但是她没有精确的感染人数规模，和结束日期