[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： [X"
k> Sq  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd');  rz  
net.trainParam.show = 50; 7'j9rmTXs  
net.trainParam.lr = 0.05; hPO>,j^  
net.trainParam.epochs = 300; 4XG]z_+I  
net.trainParam.goal = 1e-5; #x)}29%e#  
p = [-1 -1 2 2;0 5 0 5]; Jt=>-Spj  
t = [-1 -1 1 1]; iJnh$jo  
net=train(net,p,t); TmP8q  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 i?>Hr|  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 %C*^:\y  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 mK\aI  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 e-6(F4  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 .ZX2^)`XD  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 uBeNXOre  
TRAINGD, Performance goal met. YmDn+VIg  
a = sim(net,p) K`(#K#n  
plot(p,t,p,a,'o') rO^xz7K^  
但是为什么老是报错： FdxsUDL  
??? Input argument "net" is undefined. E+{5-[Zc*$