[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： F1A7l"X]  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); ^yFtL(x,  
net.trainParam.show = 50; Wm^RfxgN/  
net.trainParam.lr = 0.05; BcaX:C?f  
net.trainParam.epochs = 300; /^pPT6  
net.trainParam.goal = 1e-5; qdNt2SO  
p = [-1 -1 2 2;0 5 0 5]; ]EWEW*'j  
t = [-1 -1 1 1]; $! R]!s  
net=train(net,p,t); qP5'&!s&!  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 s(0"r.  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 I.>SC  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 TgjM@ir  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 d:!A`sk7  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 V;IV2HT0J"  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 $6DA<v^=z  
TRAINGD, Performance goal met. "8l&m6`U-  
a = sim(net,p) =\FV_4)  
plot(p,t,p,a,'o') MJ_]N+  
但是为什么老是报错： _`~\zzUZ  
??? Input argument "net" is undefined. WNO!6*+