调整参数对bp网络的影响

调整参数对bp网络的影响，具体如下：

clc; clear; x=1:1:79; P=rands(1,79); % T=rands(1,79); T=ones(1,79); net=newff(minmax(P),[25,1],{'tansig','purelin'},'trainlm'); net.trainParam.show=50; net.trainParam.epochs=200; net.trainParam.goal=0.01; net=train(net,P,T); y=sim(net,P); %%%%%%%%%%%%%%%%%%%%%%调整参数后，epochs变大，goal变小。 net2=newff(minmax(P),[25,1],{'tansig','purelin'},'trainlm'); net2.trainParam.show=50; net2.trainParam.epochs=200; net2.trainParam.goal=0.00000001; net2=train(net2,P,T); y2=sim(net2,P); %%%%%%%%绘制效果 plot(x,T,'r*'); hold on plot(x,y,'g*'); plot(x,y2,'b*'); % axis([0 80 0.999 1.001]); legend('目标值','第一次模拟效果','第二次模拟效果','Location','NorthWest'); hold off;