具體help以上三個函數
[nb,minb,maxb,na,mina,maxa]=premnmx(traindata,trainlabels);
[nc]=tramnmx(test_patterns,minb,maxb);
net=newff(minmax(traindata),[4，6,1],{'tansig',tansig','purelin'});
net=train(net,nb,na);
nd= sim(net,nc);