文档介绍:-PropagationInputlayerOutputlayerHiddenlayer+-DesiredoutputNeuronjwijxiw1jw2jwijErrorx1x2xjYj,desiredYj=g(hj)Transferfunctionujkjvjkulk+1lvlk+1uik-1ivik-1wijwjlAssumption:Transferfunction:SigmoidInputsample(xk,yk),k=1,2,…,Nujk:Totalinputtojthneurononthekthlayervjk:Outputfromjthneurononthekthlayerwij:interconnectingweightbetweentheithnodeoflayerk-1andthejthnodeoflayerkWhere,yjisthedesiredoutputminE(w,x)isthelearningrateujkjvjkulk+1lvlk+1uik-1ivik-1wijwjlAssuming:LearningformulaujkjvjkwijSigmoidfunction:+1lvlk+1uik-1ivik-1wijwjlwij,new=wij,old+wijBPalgorithm:Newweightfactor=Oldweightfactor+LearningrateInputtermGradient-(1) forwardactivationflowtocalculatevjkoneachlayerbackwarderrorflowtocalculateworkAdjustweightfactorswij,new=wij,old+wij