[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： N ;n55N  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); gF;C% }  
net.trainParam.show = 50; <iH"5DEe  
net.trainParam.lr = 0.05; &`-e; Xt  
net.trainParam.epochs = 300; X)c0y3hk  
net.trainParam.goal = 1e-5; `}}|QP5xG  
p = [-1 -1 2 2;0 5 0 5]; V.yDZ"  
t = [-1 -1 1 1]; {n<1uh9~$8  
net=train(net,p,t); f,3K;S-he:  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 |y
?W#xb  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 P`_Q-vu  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 YW8Odm  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 K!-iDaVI  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 Y]B9*^d<  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 =^zOM6E1ZF  
TRAINGD, Performance goal met. YPw=iF]  
a = sim(net,p) z}*L*Sk  
plot(p,t,p,a,'o') Qi9M4Yv  
但是为什么老是报错： 9IacZ  
??? Input argument "net" is undefined. /de~+I5AB~