使用tensorflow進行FCN網絡訓練時出現loss值是負值情況1

簡單的FCN網絡出現結果如下:

epoch=0,i=54747 of 78989, loss=-624.140625
epoch=0,i=54748 of 78989, loss=-739.443359
epoch=0,i=54749 of 78989, loss=-603.046875
epoch=0,i=54750 of 78989, loss=-594.843750
epoch=0,i=54751 of 78989, loss=-509.031250
epoch=0,i=54752 of 78989, loss=-656.093750
epoch=0,i=54753 of 78989, loss=-725.562500
epoch=0,i=54754 of 78989, loss=-589.484375
epoch=0,i=54755 of 78989, loss=-691.789062
epoch=0,i=54756 of 78989, loss=-123.398438
epoch=0,i=54757 of 78989, loss=-561.562500
epoch=0,i=54758 of 78989, loss=-554.531250
epoch=0,i=54759 of 78989, loss=-557.578125
epoch=0,i=54760 of 78989, loss=-543.281250
epoch=0,i=54761 of 78989, loss=-592.968750

經過驗證,是softmax與sigmoid函數選擇不恰當,本人做的是兩分類,換成sigmoid函數計算loss之後,發現所有的loss值固定爲一個數,在此之前deconv是沒有加入bias的,當最後加入bias訓練之後,得到的結果如下所示:

epoch=7,i=57416 of 78989, loss=-44566832.000000
epoch=7,i=57417 of 78989, loss=-27127590.000000
epoch=7,i=57418 of 78989, loss=-27127606.000000
epoch=7,i=57419 of 78989, loss=-33217624.000000
epoch=7,i=57420 of 78989, loss=-35709012.000000
epoch=7,i=57421 of 78989, loss=-45951332.000000
epoch=7,i=57422 of 78989, loss=-29065516.000000

去掉bias之後,結果如下

epoch=0,i=22875 of 78989, loss=798.504578
epoch=0,i=22876 of 78989, loss=798.504578
epoch=0,i=22877 of 78989, loss=798.504578
epoch=0,i=22878 of 78989, loss=798.504578
epoch=0,i=22879 of 78989, loss=798.504578
epoch=0,i=22880 of 78989, loss=798.504578
epoch=0,i=22881 of 78989, loss=798.504578
epoch=0,i=22882 of 78989, loss=798.504578

固定爲一個值不動,經過重新試驗,我將fcn網絡的最後一層的softmax改爲了sigmoid函數之後,結果如下:

epoch=6,i=693 of 78989, loss=798.504578
epoch=6,i=694 of 78989, loss=798.504578
epoch=6,i=695 of 78989, loss=798.504578
epoch=6,i=696 of 78989, loss=798.504578
epoch=6,i=697 of 78989, loss=798.504578
epoch=6,i=698 of 78989, loss=798.504578

還是固定爲同一個值不變,可能陷入局部最優解,將學習率從0.0001調整爲0.001之後,結果如下所示:

epoch=6,i=696 of 78989, loss=798.504578
epoch=6,i=697 of 78989, loss=798.504578
epoch=6,i=698 of 78989, loss=798.504578

繼續調整學習率到0.01,結果不變。即跟學習率無關。

繼續探索原因,後續會補上結果。

 

 

 

 

 

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