[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： 1u(n[<WtT_  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); H6Gs&yk3  
net.trainParam.show = 50; u yE#EnsH  
net.trainParam.lr = 0.05; D=Yr/qc?  
net.trainParam.epochs = 300; 1N5lI97j  
net.trainParam.goal = 1e-5; Eb CK9  
p = [-1 -1 2 2;0 5 0 5]; :@@m'zF<;  
t = [-1 -1 1 1]; =EU;%f  
net=train(net,p,t); 4Y4zBD=<  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 }r;=<mc,O  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 &5G@YQD1e  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 cmq4w&x/  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 1=`VaS  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 2]FRIy d  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 oMOh4NH,x  
TRAINGD, Performance goal met. fr$6&HDZ9  
a = sim(net,p) ""_B3'  
plot(p,t,p,a,'o') iOL/u)   
但是为什么老是报错： xuVc1jJH  
??? Input argument "net" is undefined. c6y>]8_