[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： 9$`lIy@B  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); _=CZR7:O  
net.trainParam.show = 50; B#/Q'V  
net.trainParam.lr = 0.05; oF(Lji?m  
net.trainParam.epochs = 300; 5p.rwNE  
net.trainParam.goal = 1e-5; >D201&*G%  
p = [-1 -1 2 2;0 5 0 5]; 7$h#OV*@,  
t = [-1 -1 1 1]; P) 3mX.(}  
net=train(net,p,t); T^J>ZDA  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 -'~LjA(  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 b[V^86X^  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 5onm]V]  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 Vz6Qxd{m3  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 p+)YTzzc  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 B,,D7cQC  
TRAINGD, Performance goal met.
&gzCteS  
a = sim(net,p) o,|[GhtHqs  
plot(p,t,p,a,'o') lz1wO5%h  
但是为什么老是报错： ~ vqa7~}m  
??? Input argument "net" is undefined. OS8q( 2z?s