[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： li,kW`j+t  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); RSzp-sKB  
net.trainParam.show = 50; |0A n|18  
net.trainParam.lr = 0.05; />.&  
net.trainParam.epochs = 300; m <aMb  
net.trainParam.goal = 1e-5; ,Ad\!  
p = [-1 -1 2 2;0 5 0 5]; (;C_>EL&u  
t = [-1 -1 1 1]; Z37Z  
net=train(net,p,t); bbA+ZLZJn  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 ||9f@9  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 ]-L/Of6F)|  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 8I NVn'G  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 .J&~u0g  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 #q(BR{A>t  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 ;bkS0Vmg  
TRAINGD, Performance goal met. >Py;6K  
a = sim(net,p) ;cxYX/fJ  
plot(p,t,p,a,'o') ,7>_Lp_v  
但是为什么老是报错： g)u2  
??? Input argument "net" is undefined. kd!f/'E!