[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： +JoE[;  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); C2RR(n=N^  
net.trainParam.show = 50; 8F|8zX&  
net.trainParam.lr = 0.05; "Sp+Q&2U  
net.trainParam.epochs = 300; ssVO+ T  
net.trainParam.goal = 1e-5; u^H:z0  
p = [-1 -1 2 2;0 5 0 5]; l]Ozy@ Ib  
t = [-1 -1 1 1]; fpbb <Ro  
net=train(net,p,t); 4:\1S~WW  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 G0p|44_~t  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 v'Y)~Kv@!  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 Bbuy y  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 '51DdT
U  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 )rJ{}U:S  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 ax{+7 k  
TRAINGD, Performance goal met. '@1oM1  
a = sim(net,p) a f[<[2pma  
plot(p,t,p,a,'o') .kWMr^ g  
但是为什么老是报错： $]:ycn9l  
??? Input argument "net" is undefined. [4uTp[U!r