[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： q/U-6A[0  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); *"8Ls0!  
net.trainParam.show = 50; 4)8VmCW  
net.trainParam.lr = 0.05; K-C,n~-  
net.trainParam.epochs = 300; (?\+
  
net.trainParam.goal = 1e-5; 1Y'4 g3T  
p = [-1 -1 2 2;0 5 0 5]; d6QrB"J`  
t = [-1 -1 1 1]; }p
sRgF  
net=train(net,p,t); }l7+W4~  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 >[|N%9\  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 c]ARgrH-  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 X n!mdR  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 %/y=_G  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 ~SQxFAto  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 +n;nvf}(  
TRAINGD, Performance goal met. 7amVnR1f  
a = sim(net,p) Om0$6O  
plot(p,t,p,a,'o') pVy=rS-  
但是为什么老是报错： nFEJO&1+  
??? Input argument "net" is undefined. EYq?NL='