我正在通過使用隨機梯度下降的反向傳播訓練XOR神經網絡。神經網絡的權重被初始化爲-0.5和0.5之間的隨機值。大約80%的時間,神經網絡成功地進行自我訓練。但是有時它會在反向傳播時「卡住」。通過「卡住」,我的意思是我開始看到錯誤糾正率在下降。舉例來說,一個成功的培訓過程中,總的錯誤,而迅速減小作爲網絡學習,像這樣:XOR神經網絡錯誤在訓練期間停止減少
...
...
Total error for this training set: 0.0010008071327708653
Total error for this training set: 0.001000750550254843
Total error for this training set: 0.001000693973929822
Total error for this training set: 0.0010006374037948094
Total error for this training set: 0.0010005808398488103
Total error for this training set: 0.0010005242820908169
Total error for this training set: 0.0010004677305198344
Total error for this training set: 0.0010004111851348654
Total error for this training set: 0.0010003546459349181
Total error for this training set: 0.0010002981129189812
Total error for this training set: 0.0010002415860860656
Total error for this training set: 0.0010001850654351723
Total error for this training set: 0.001000128550965301
Total error for this training set: 0.0010000720426754587
Total error for this training set: 0.0010000155405646494
Total error for this training set: 9.99959044631871E-4
Testing trained XOR neural network
0 XOR 0: 0.023956746649767453
0 XOR 1: 0.9736079194769579
1 XOR 0: 0.9735670067093437
1 XOR 1: 0.045068688874314006
然而,當它被卡住,總誤差減小,但它似乎是一定的下降速度:
...
...
Total error for this training set: 0.12325486644721295
Total error for this training set: 0.12325486642503929
Total error for this training set: 0.12325486640286581
Total error for this training set: 0.12325486638069229
Total error for this training set: 0.12325486635851894
Total error for this training set: 0.12325486633634561
Total error for this training set: 0.1232548663141723
Total error for this training set: 0.12325486629199914
Total error for this training set: 0.12325486626982587
Total error for this training set: 0.1232548662476525
Total error for this training set: 0.12325486622547954
Total error for this training set: 0.12325486620330656
Total error for this training set: 0.12325486618113349
Total error for this training set: 0.12325486615896045
Total error for this training set: 0.12325486613678775
Total error for this training set: 0.12325486611461482
Total error for this training set: 0.1232548660924418
Total error for this training set: 0.12325486607026936
Total error for this training set: 0.12325486604809655
Total error for this training set: 0.12325486602592373
Total error for this training set: 0.12325486600375107
Total error for this training set: 0.12325486598157878
Total error for this training set: 0.12325486595940628
Total error for this training set: 0.1232548659372337
Total error for this training set: 0.12325486591506139
Total error for this training set: 0.12325486589288918
Total error for this training set: 0.12325486587071677
Total error for this training set: 0.12325486584854453
雖然我是在我遇到的討論來到當地最低高度和全球最低高度和網絡如何神經真的不「知道」,這極小它應該是逐步轉向神經網絡閱讀起來。
我的網絡陷入局部極小值而不是全局極小值?
謝謝!你的回答更清晰。看起來,神經網絡並不精確,涉及到一定程度的混亂。我會嘗試改變周圍的參數並嘗試讓問題消失。 –
我碰到了[本文](http://www.ncbi.nlm.nih.gov/pubmed/18252598)(發表於1999年,在你引用的那年的一年後),它說, 2-3-1 XOR網絡(我正在使用3-3-1 XOR網絡;不確定是否需要輸入層上的偏差)。再次,就像你的情況一樣,這是一個抽象。 –
我還看到了[本文](http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CDMQFjAC&url=http%3A%2F%2Fciteseerx.ist.psu.edu %2Fviewdoc%2Fdownload%3Fdoi%3D10.1.1.31.4770%26rep%3Drep1%26type%3Dpdf&ei = -WK5TqjAGIaviAL636jTBA&usg = AFQjCNEaQ0jG2bkD4ipXcfgXDr9mHrxRMQ&sig2 = BD8IyRc8Clg2XftdR20W9w)表示最簡單的XOR網絡沒有最小值,但這似乎不是2-3-1或3-3-1網絡。 –