[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： 1h#UM6  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); e.?;mD  
net.trainParam.show = 50; B{\qYL/~  
net.trainParam.lr = 0.05; Y<9]7R(\;  
net.trainParam.epochs = 300; i
!dQ Sdf  
net.trainParam.goal = 1e-5; +o^sm'$  
p = [-1 -1 2 2;0 5 0 5]; YB3?Ftgw  
t = [-1 -1 1 1]; El4SL'E@  
net=train(net,p,t); .[8g6:>  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 P*.0kR1n  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 I2^Eo5'  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 [3fmhc  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 }D7} %P]  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 (|U|>@  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 z{ MO~d9  
TRAINGD, Performance goal met. ;LE9w^>^V  
a = sim(net,p) J\c\
Ar:  
plot(p,t,p,a,'o') W:* {7qJ  
但是为什么老是报错： !<W^Fh  
??? Input argument "net" is undefined. SQJ }$#=