摘要
为了减小标准BP算法中迭代次数并提高其收敛速度 ,现提出将负梯度下降法与DFP变尺度算法相结合进行权值修正的方法 .在误差寻优初期 ,首先采用标准BP算法进行迭代 ,每迭代一次的工作量较小、所需存贮量较少 ,且对初始点的要求不高 .然后 ,当寻优过程开始接近最优时 ,更改寻优算法 ,即使用DFP变尺度算法 .最后 ,运用MATLAB工具箱和VisualBasic实现算例 .实验结果表明 :改进后的BP算法减少了迭代次数 。
In order to reduce the times of substitution on standard BP algorithm and improve the speed of convergence,a new method,which integrated minus-grade decline way with DFP algorithm,has been presented.In the initial stages of seeking optimization,standard BP algorithm should be used.Then the task of one substitution would be less than others and the store capacity would be smaller.Furthermore,it has an inferior demand for the initial value.When the process of seeking optimization began to approach optimization,DFP algorithm should be used.Finally,MATLAB toolbox and Visual Basic can realize the improved algorithm.The result of experiment showed that the new algorithm can reduce the times of substitution and improve the speed of convergence efficiently.
