[求助]新手求助~（关于初级的神经网络问题） [复制链接]

各位大虾，我在网上看到的教程里的一个程序段，本来想要试试看的： ]FCP|Jz  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); 7}&:07U  
net.trainParam.show = 50; -leX|U}k  
net.trainParam.lr = 0.05; B@F@,?K4%  
net.trainParam.epochs = 300; o-6d$c}{f  
net.trainParam.goal = 1e-5; \D|IN'!D  
p = [-1 -1 2 2;0 5 0 5]; AM-bs^  
t = [-1 -1 1 1];
H9)@q3<  
net=train(net,p,t); #I=EYl=Vvi  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 \:;MFG'  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 u ON(LavB  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 VKttJok1  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 `=Ip>7T&  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 (H_dZL  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 B[Lm}B[  
TRAINGD, Performance goal met. m|q,ixg  
a = sim(net,p) h]<S0/  
plot(p,t,p,a,'o') G[KjK$.Ts?  
但是为什么老是报错： 2u$-(JfoS  
??? Input argument "net" is undefined. W{;Qi&^ca