[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： ">G*hS  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); qTK(sW  
net.trainParam.show = 50; `<|tC#<z  
net.trainParam.lr = 0.05; %*szB$[3  
net.trainParam.epochs = 300; D+v?zQw  
net.trainParam.goal = 1e-5; n 7i5A:  
p = [-1 -1 2 2;0 5 0 5]; #6vf:94  
t = [-1 -1 1 1]; Xy%||\P{)  
net=train(net,p,t); IIih9I`IR  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 =.7tS'  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 5+11J[~{  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 7)]boW~Q  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 Pjk2tf0j`  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 V'e%%&g~N  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 sQ340!  
TRAINGD, Performance goal met. mZ2CGOR  
a = sim(net,p) @!=Ds'MJC  
plot(p,t,p,a,'o') l;KrFJ6  
但是为什么老是报错： u178vby;l  
??? Input argument "net" is undefined. c+&Kq.~K