[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： V588Leb?  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); L7g&]%  
net.trainParam.show = 50; 5 QeGx3'  
net.trainParam.lr = 0.05; 3oKGeB;Ja  
net.trainParam.epochs = 300; HLk"a-+'  
net.trainParam.goal = 1e-5; </Id';|v  
p = [-1 -1 2 2;0 5 0 5]; 8.^U6xA  
t = [-1 -1 1 1]; z]YhQIU4n8  
net=train(net,p,t); \,EPsQV0?  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 >(rB[ZJ  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 =tNiIU  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 ^zJ.W  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 `|w#K28t"  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 "{k )nr+7U  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 8_m9CQ6 i  
TRAINGD, Performance goal met. t/1NTa  
a = sim(net,p) PPPwDsJ  
plot(p,t,p,a,'o') wUeOD.;#F  
但是为什么老是报错： 9/M!S[N9  
??? Input argument "net" is undefined. eh>E).