[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： ht_'GBS)  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); Cs'<;|r(  
net.trainParam.show = 50; #pnB+h&tE  
net.trainParam.lr = 0.05; Cg3 d  
net.trainParam.epochs = 300; c&'5r OY~  
net.trainParam.goal = 1e-5; &P&VJLAe  
p = [-1 -1 2 2;0 5 0 5]; W|(U}PrC  
t = [-1 -1 1 1]; !g4u<7  
net=train(net,p,t); ^4Tf6Fw#  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 F$@(0c  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 ;T :]?5W!  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 M \UB r4  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 0y`r.)G  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 R1~wzy  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 B &e'n
<  
TRAINGD, Performance goal met. 3QDz9KwCAw  
a = sim(net,p) Ya;y@44  
plot(p,t,p,a,'o') Z '~Ie~  
但是为什么老是报错： G=PX'dS  
??? Input argument "net" is undefined. 9`tSg!YOh