[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： R]8^ @i1  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); tUR9ti  
net.trainParam.show = 50; e_{!8u.+  
net.trainParam.lr = 0.05; 28rC>*+z  
net.trainParam.epochs = 300; H*&ZXAKv  
net.trainParam.goal = 1e-5; ?5
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p = [-1 -1 2 2;0 5 0 5]; Pu-/*Fx  
t = [-1 -1 1 1]; <F7g;s'q9  
net=train(net,p,t); }G50?"^u  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 sKLH.@  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 m?$peRn3{  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 )rP)-op|A  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 3jG #<4;J  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 ^%<t^sE  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 AT6:&5_`  
TRAINGD, Performance goal met. 5HAIK
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a = sim(net,p) vKC
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plot(p,t,p,a,'o') 7:>VH>?D  
但是为什么老是报错： Y3J;Kk#AH  
??? Input argument "net" is undefined. V7qc9Gd@I