[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： %Va!\#  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); $H9%J  
net.trainParam.show = 50; L=sYLC6d  
net.trainParam.lr = 0.05; #odIEC/  
net.trainParam.epochs = 300; A*/HjTX  
net.trainParam.goal = 1e-5; j+,d^!  
p = [-1 -1 2 2;0 5 0 5]; "*srx]  
t = [-1 -1 1 1]; aD$v2)RR  
net=train(net,p,t); 3 C<L  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 l.NEkAYPmH  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 Us0EG\Y  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 /VN f{p  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 [.uG5%fa  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 |* ;B  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 )j0TeE1R  
TRAINGD, Performance goal met. /q`xCS  
a = sim(net,p) [c|]f_ZdK  
plot(p,t,p,a,'o') ikvWh<=>H  
但是为什么老是报错： 5jgR4a*_v  
??? Input argument "net" is undefined. 5?F__Hx*2