[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： }3WxZv]I}  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); Y"$xX8o
  
net.trainParam.show = 50; uHRsFlw  
net.trainParam.lr = 0.05; S~G]~gt  
net.trainParam.epochs = 300; ;*2Cm'8E  
net.trainParam.goal = 1e-5; QIFgQ0{  
p = [-1 -1 2 2;0 5 0 5]; r
Ez^  
t = [-1 -1 1 1]; '8kP.l  
net=train(net,p,t); C\hM =%  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 &_8947  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 1s;Saq+  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 _Y m2/3!  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 |CbikE}kL  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 7tCw*t$  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 Bk{]g=DO  
TRAINGD, Performance goal met. as=fCuJ  
a = sim(net,p) V>rU.Mp QU  
plot(p,t,p,a,'o') SSzIih@u  
但是为什么老是报错： NDokSw-  
??? Input argument "net" is undefined. Zx>=t
x}