[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： m?-3j65z  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); b r)oSw  
net.trainParam.show = 50; [ADr _  
net.trainParam.lr = 0.05; A)En25,X  
net.trainParam.epochs = 300; lTPo2-j/eK  
net.trainParam.goal = 1e-5; (US]e un  
p = [-1 -1 2 2;0 5 0 5]; 8WU UE=p  
t = [-1 -1 1 1]; XM3N>OR.  
net=train(net,p,t); =+q9R`!L]  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 2Z6#3~  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 euM7> $`  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 Q7$
ILW-S  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 buGW+TrWY  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10
F\+
wM*:U  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 hS&,Gm`^  
TRAINGD, Performance goal met. /-<S F
T`  
a = sim(net,p) fGJ
PZe  
plot(p,t,p,a,'o') nBL7LocvR  
但是为什么老是报错： |")}p=   
??? Input argument "net" is undefined. i8I%}8