Merge pull request #957 from PaddlePaddle/ds2_offline

revert ds2 offline rnn bw_cell to fw_cell which loss can be 5.73

deepspeech/models/ds2/rnn.py

@@ -202,7 +202,7 @@ class BiRNNWithBN(nn.Layer):
         self.fw_rnn = nn.RNN(
             self.fw_cell, is_reverse=False, time_major=False)  #[B, T, D]
         self.bw_rnn = nn.RNN(
-            self.bw_cell, is_reverse=True, time_major=False)  #[B, T, D]
+            self.fw_cell, is_reverse=True, time_major=False)  #[B, T, D]
 
     def forward(self, x: paddle.Tensor, x_len: paddle.Tensor):
         # x, shape [B, T, D]
@@ -246,7 +246,7 @@ class BiGRUWithBN(nn.Layer):
         self.fw_rnn = nn.RNN(
             self.fw_cell, is_reverse=False, time_major=False)  #[B, T, D]
         self.bw_rnn = nn.RNN(
-            self.bw_cell, is_reverse=True, time_major=False)  #[B, T, D]
+            self.fw_cell, is_reverse=True, time_major=False)  #[B, T, D]
 
     def forward(self, x, x_len):
         # x, shape [B, T, D]

examples/aishell/s0/README.md

@@ -4,9 +4,7 @@
 
 | Model | Params | Release | Config | Test set | Loss | CER |  
 | --- | --- | --- | --- | --- | --- | --- |  
-| DeepSpeech2 | 58.4M | 2.2.0 | conf/deepspeech2.yaml + spec aug | test | 6.016139030456543 | 0.066549 |  
-| --- | --- | --- | --- | --- | --- | --- |  
-| DeepSpeech2 | 58.4M | 7181e427 | conf/deepspeech2.yaml + spec aug | test | 5.71956205368042 | 0.064287 |  
+| DeepSpeech2 | 58.4M | 2.2.0 | conf/deepspeech2.yaml + spec aug | test | 5.71956205368042 | 0.064287 |  
 | DeepSpeech2 | 58.4M | 2.1.0 | conf/deepspeech2.yaml + spec aug | test | 7.483316898345947 | 0.077860 |  
 | DeepSpeech2 | 58.4M | 2.1.0 | conf/deepspeech2.yaml | test | 7.299022197723389 | 0.078671 |
 | DeepSpeech2 | 58.4M | 2.0.0 | conf/deepspeech2.yaml | test | - | 0.078977 |  

examples/aishell/s0/conf/deepspeech2.yaml

@@ -41,7 +41,7 @@ model:
   use_gru: True 
   share_rnn_weights: False
   blank_id: 0
-  ctc_grad_norm_type: null
+  ctc_grad_norm_type: instance 
 
 training:
   n_epoch: 80