[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： \~z?PA.$  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); H)j[eZP  
net.trainParam.show = 50; z,}c?BP  
net.trainParam.lr = 0.05; ~C/Yv&58  
net.trainParam.epochs = 300; "LP, TC  
net.trainParam.goal = 1e-5; _A;v
Sp.`  
p = [-1 -1 2 2;0 5 0 5]; `Ct'/h{  
t = [-1 -1 1 1]; dJ%wVY0z=  
net=train(net,p,t); k7yv>iN  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 V5e\%  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 #514a(6  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 B&4fYpn  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 5eiZs  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 ibZt2@GB)I  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 TZ&4  
TRAINGD, Performance goal met. ^MWEfPt  
a = sim(net,p) 3:]{(@J  
plot(p,t,p,a,'o') )X
mCy"xx  
但是为什么老是报错： w|!YoMk+o  
??? Input argument "net" is undefined. Xk{!' 0