[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： s^9Voi.y  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); M FMs[+2_o  
net.trainParam.show = 50; |aS.a&vwR  
net.trainParam.lr = 0.05; H$t_Xw==  
net.trainParam.epochs = 300; xm~`7~nFR  
net.trainParam.goal = 1e-5; 4E+e}\r:6  
p = [-1 -1 2 2;0 5 0 5]; k]|~>9eY]  
t = [-1 -1 1 1]; J!(<y(l  
net=train(net,p,t);
7xlkZF  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 vn8aFA  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 U'_Q>k  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 Pmx-8w  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 cqkV9f8Ro  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 4F:\-O  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 z&\a:fJ&  
TRAINGD, Performance goal met. `
/+>a8  
a = sim(net,p) #:_Kws>+  
plot(p,t,p,a,'o') [|$h*YK  
但是为什么老是报错： ebhXak[w  
??? Input argument "net" is undefined. Bkc4TO