[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： e|y~q0Q$  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); [wYQP6Cyy  
net.trainParam.show = 50; o 4wKu  
net.trainParam.lr = 0.05; &|*|  
net.trainParam.epochs = 300;
t/(j8w  
net.trainParam.goal = 1e-5; Pw.+DA  
p = [-1 -1 2 2;0 5 0 5]; z8MYgn7  
t = [-1 -1 1 1]; -&tiM v  
net=train(net,p,t); Vd~k4  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 4{E=wg^p  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 ')<$AMy1  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 SBt: `,  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 Pw{+7b$  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 ]uf_"D  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 aR $P}]H  
TRAINGD, Performance goal met. p(%x&*)f  
a = sim(net,p) +__Rk1CVh  
plot(p,t,p,a,'o') %Kp}Wo6  
但是为什么老是报错： 1XRVbQt  
??? Input argument "net" is undefined. 1qF.0