[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： p-6(>,+E[  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); UB4M=R|  
net.trainParam.show = 50; <0,szw  
net.trainParam.lr = 0.05; ;M95A  
net.trainParam.epochs = 300; L&i_  
net.trainParam.goal = 1e-5; S!u`V3-s  
p = [-1 -1 2 2;0 5 0 5]; cITF=Ez  
t = [-1 -1 1 1]; yXpU)|o  
net=train(net,p,t); `D#3  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 bhIyq4N  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 5:=ECtKi  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 K~?M?sa  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 XO=UKk+EK  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 _QhB0/C  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 @k~_ w#  
TRAINGD, Performance goal met. )k@+8Yfa1p  
a = sim(net,p) (IrX
\Y  
plot(p,t,p,a,'o') *@C4~Zo  
但是为什么老是报错： rRfPq  
??? Input argument "net" is undefined. `wyX)6A|bt