[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： :9x]5;ma  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); >o&%via}  
net.trainParam.show = 50; 1P'L<z  
net.trainParam.lr = 0.05; S5Pn6'w  
net.trainParam.epochs = 300; *A}td8(  
net.trainParam.goal = 1e-5; _/.VXW  
p = [-1 -1 2 2;0 5 0 5]; hBaG*J{  
t = [-1 -1 1 1]; *}Z  
net=train(net,p,t); Y$)y:.2#  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 QGGBI Ku   
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 dNqj|Vu  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 ZZ :*c"b:  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 Fe$o*r,  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 0(Z:QqpU$  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 /P46k4M1U  
TRAINGD, Performance goal met. C8)s6  
a = sim(net,p) `fJ;4$4  
plot(p,t,p,a,'o') xdaq` ^Bbt  
但是为什么老是报错： =JPY{'VO  
??? Input argument "net" is undefined. ]]}iSw'