插值%产生原始数据x=0:0.1:1;y=(x.^2-3*x+7).*exp(-4*x).*sin(2*x);%线性插值xx=0:0.01:1;y1=interp1(x,y,xx,'linear');subplot(2,2,1)plot(x,y,'o',xx,y1);title('线性插值');%最邻近点插值y2=interp1(x,y,xx,'nearest');subplot(2,2,2)plot(x,y,'o',xx,y2);title('最邻近点插值');%三次插值y3=interp1(x,y,xx,'cubic');subplot(2,2,3)plot(x,y,'o',xx,y3);title('三次插值');%三次样条插值y4=interp1(x,y,xx,'spline');subplot(2,2,4)plot(x,y,'o',xx,y4);title('三次样条插值');%插值基点为网格节点clearally=20:-1:0;x=0:20;z=[0.20.20.20.20.20.20.40.40.30.20.30.20.10.20.20.40.30.20.20.20.2;0.30.20.20.20.20.40.30.30.30.30.40.20.20.20.20.40.40.40.30.20.2;0.20.30.30.20.310.40.50.30.30.30.30.20.20.20.60.50.40.40.20.2;0.20.20.40.211.10.90.40.30.30.50.30.20.20.20.70.30.60.60.30.4;0.20.20.90.71110.70.50.30.20.20.20.60.20.80.70.90.50.50.4;0.20.31111.211.10.80.30.20.20.20.50.30.60.60.80.70.60.5;0.20.4111.11.11.11.10.60.30.40.40.20.70.50.90.70.40.90.80.3;精选文库—20.20.20.91.11.21.21.11.10.60.30.50.30.20.40.30.710.71.20.80.4;0.20.30.40.91.111.11.10.70.40.40.40.30.50.50.81.10.81.10.90.3;0.30.30.51.21.21.111.20.90.50.60.40.60.60.30.61.20.810.80.5;0.30.50.91.11.111.210.80.70.50.60.40.50.411.30.90.910.8;0.30.50.61.11.2111.10.90.40.40.50.50.80.60.910.50.80.80.9;0.40.50.411.11.210.90.70.50.60.30.60.40.6110.60.910.7;0.30.50.81.11.110.80.70.70.40.50.40.40.50.41.11.30.710.70.6;0.30.50.91.110.70.70.40.60.40.40.30.50.50.30.91.20.810.80.4;0.20.30.60.90.80.80.60.30.40.50.40.50.40.20.50.51.30.610.90.3;0.20.30.30.70.60.60.40.20.30.50.80.80.30.20.20.81.30.90.80.80.4;0.20.30.30.60.30.40.30.20.20.30.60.40.30.20.40.30.80.60.70.40.4;0.20.30.40.40.20.20.20.30.20.20.20.20.20.20.20.50.70.40.40.30.3;0.20.20.30.20.20.30.20.20.20.20.20.10.20.40.30.60.50.30.30.30.2;0.20.20.20.20.20.20.20.20.20.20.20.20.20.20.40.70.40.20.40.50.5];%未插值直接画图figure(1)%创建图形窗口1，并激活surf(x,y,z);shadingflat%用shadingflat命令，使曲面变的光滑title('未插值地形图')xlabel('横坐标')ylabel('纵坐标')zlabel('高度')%三次插值后画图%画地形图figure(2)xi=0:0.05:20;yi=20:-0.05:0;精选文库—3zi=interp2(x,y,z,xi',yi,'cubic');%'cubic'三次插值surfc(xi,yi,zi);%底面带等高线shadingflattitle('插值后地形图')xlabel('横坐标')ylabel('纵坐标')zlabel('高度')%画立体等高线图figure(3)contour3(xi,yi,zi);title('立体等高线图')xlabel('横坐标')ylabel('纵坐标')zlabel('高度')%画等高线图figure(4)[c,h]=contour(xi,yi,zi);clabel(c,h);%用于为2维等高线添加标签colormapcool%冷色调title('平面等高线图')xlabel('横坐标')ylabel('纵坐标')ge回归拟合functionyhat=Logisfun(beta,x)yhat=beta(1)./(1+(beta(1)/beta(2)-1).*exp(-beta(3).*x));clearally=[3.95.37.29.612.917.123.231.438.650.262.9...76.092.0106.5123.2131.7150.7179.3204.0226.5251.4281.4]';x=(1:22)';beta0=[400,3.0,0.20]';%非线性回归'Logisfun'为回归模型[beta,r,j]=nlinfit(x,y,'Logisfun',beta0);%beta0为回归系数初始迭代点%beta为回归系数%r为残差%输出拟合表达式:fprintf('回归方程为y=%5.4f/(1+%5.4f*exp(-%5.4f*x))\n',beta(1),beta(1)/beta(2)-1,beta(3))%求均方误差根:精选文库—4rmse=sqrt(sum(r.^2)/22);rmse%预测和误差估计：[Y,DELTA]=nlpredci('Logisfun',x,beta,r,j);%DELTA为误差限%Y为预测值(拟合后的表达式求值)plot(x,Y,x,y,'o',x,Y+DELTA,':',x,Y-DELTA,':')%lny=lna+bxclearally=[3.95.37.29.612.917.123.231.438.650.262.976.0];%Y为列向量Y=log(y');x=1:12;%X为两列X=[ones(12,1),x'];[b,bint,r,rint,stats]=regress(Y,X);%b为参数的点估计disp('b为参数的点估计')b%bint为参数的区间估计disp(...
