修改了deepspeech2.py部分LSTM和GRU的代码，增加了LayerNorm

deepspeech/exps/deepspeech2/model.py

@@ -127,7 +127,8 @@ class DeepSpeech2Trainer(Trainer):
             num_rnn_layers=config.model.num_rnn_layers,
             rnn_size=config.model.rnn_layer_size,
             use_gru=config.model.use_gru,
-            share_rnn_weights=config.model.share_rnn_weights)
+            share_rnn_weights=config.model.share_rnn_weights,
+            apply_online=config.model.apply_online)
 
         if self.parallel:
             model = paddle.DataParallel(model)
@@ -374,7 +375,8 @@ class DeepSpeech2Tester(DeepSpeech2Trainer):
             num_rnn_layers=config.model.num_rnn_layers,
             rnn_size=config.model.rnn_layer_size,
             use_gru=config.model.use_gru,
-            share_rnn_weights=config.model.share_rnn_weights)
+            share_rnn_weights=config.model.share_rnn_weights,
+            apply_online=config.model.apply_online)
         self.model = model
         logger.info("Setup model!")
 

deepspeech/models/ds2/deepspeech2.py

@@ -25,6 +25,11 @@ from deepspeech.utils import layer_tools
 from deepspeech.utils.checkpoint import Checkpoint
 from deepspeech.utils.log import Log
 
+from paddle.nn import LSTM, GRU
+from paddle.nn import LayerNorm
+from paddle.nn import LayerList
+
+
 logger = Log(__name__).getlog()
 
 __all__ = ['DeepSpeech2Model', 'DeepSpeech2InferMode']
@@ -38,25 +43,50 @@ class CRNNEncoder(nn.Layer):
                  num_rnn_layers=3,
                  rnn_size=1024,
                  use_gru=False,
-                 share_rnn_weights=True):
+                 share_rnn_weights=True,
+                 apply_online=True):
         super().__init__()
         self.rnn_size = rnn_size
         self.feat_size = feat_size  # 161 for linear
         self.dict_size = dict_size
-
+        self.num_rnn_layers = num_rnn_layers
+        self.apply_online = apply_online
         self.conv = ConvStack(feat_size, num_conv_layers)
 
         i_size = self.conv.output_height  # H after conv stack
+        
+    
+        self.rnn = LayerList()
+        self.layernorm_list = LayerList()
+
+        if (apply_online == True):
+            rnn_direction = 'forward'
+        else:
+            rnn_direction = 'bidirect'        
+
+        if use_gru == True:
+            self.rnn.append(GRU(input_size=i_size, hidden_size=rnn_size, num_layers=1, direction = rnn_direction))
+            self.layernorm_list.append(LayerNorm(rnn_size))
+            for i in range(1, num_rnn_layers):
+                self.rnn.append(GRU(input_size=rnn_size, hidden_size=rnn_size, num_layers=1, direction = rnn_direction))
+                self.layernorm_list.append(LayerNorm(rnn_size))
+        else:
+            self.rnn.append(LSTM(input_size=i_size, hidden_size=rnn_size, num_layers=1, direction = rnn_direction))
+            self.layernorm_list.append(LayerNorm(rnn_size))
+            for i in range(1, num_rnn_layers):
+                self.rnn.append(LSTM(input_size=rnn_size, hidden_size=rnn_size, num_layers=1, direction = rnn_direction))
+                self.layernorm_list.append(LayerNorm(rnn_size))
+        """
         self.rnn = RNNStack(
             i_size=i_size,
             h_size=rnn_size,
             num_stacks=num_rnn_layers,
             use_gru=use_gru,
             share_rnn_weights=share_rnn_weights)
-
+        """
     @property
     def output_size(self):
-        return self.rnn_size * 2
+        return self.rnn_size
 
     def forward(self, audio, audio_len):
         """Compute Encoder outputs
@@ -86,7 +116,15 @@ class CRNNEncoder(nn.Layer):
         x = x.reshape([0, 0, -1])  #[B, T, C*D]
 
         # remove padding part
-        x, x_lens = self.rnn(x, x_lens)  #[B, T, D]
+        print ("x.shape:", x.shape)
+        x, output_state = self.rnn[0](x, None, x_lens)
+        x = self.layernorm_list[0](x)
+        for i in range(1, self.num_rnn_layers):
+            x, output_state = self.rnn[i](x, output_state, x_lens)    #[B, T, D]
+            x = self.layernorm_list[i](x)
+        """
+        x, x_lens = self.rnn(x, x_lens)          
+        """
         return x, x_lens
 
 
@@ -141,7 +179,8 @@ class DeepSpeech2Model(nn.Layer):
                  num_rnn_layers=3,
                  rnn_size=1024,
                  use_gru=False,
-                 share_rnn_weights=True):
+                 share_rnn_weights=True,
+                 apply_online = True):
         super().__init__()
         self.encoder = CRNNEncoder(
             feat_size=feat_size,
@@ -150,8 +189,9 @@ class DeepSpeech2Model(nn.Layer):
             num_rnn_layers=num_rnn_layers,
             rnn_size=rnn_size,
             use_gru=use_gru,
-            share_rnn_weights=share_rnn_weights)
-        assert (self.encoder.output_size == rnn_size * 2)
+            share_rnn_weights=share_rnn_weights,
+            apply_online=apply_online)
+        assert (self.encoder.output_size == rnn_size)
 
         self.decoder = CTCDecoder(
             odim=dict_size,  # <blank> is in  vocab
@@ -221,7 +261,8 @@ class DeepSpeech2Model(nn.Layer):
                     num_rnn_layers=config.model.num_rnn_layers,
                     rnn_size=config.model.rnn_layer_size,
                     use_gru=config.model.use_gru,
-                    share_rnn_weights=config.model.share_rnn_weights)
+                    share_rnn_weights=config.model.share_rnn_weights,
+                    apply_online=config.model.apply_online)
         infos = Checkpoint().load_parameters(
             model, checkpoint_path=checkpoint_path)
         logger.info(f"checkpoint info: {infos}")
@@ -237,7 +278,8 @@ class DeepSpeech2InferModel(DeepSpeech2Model):
                  num_rnn_layers=3,
                  rnn_size=1024,
                  use_gru=False,
-                 share_rnn_weights=True):
+                 share_rnn_weights=True,
+                 apply_online = True):
         super().__init__(
             feat_size=feat_size,
             dict_size=dict_size,
@@ -245,7 +287,8 @@ class DeepSpeech2InferModel(DeepSpeech2Model):
             num_rnn_layers=num_rnn_layers,
             rnn_size=rnn_size,
             use_gru=use_gru,
-            share_rnn_weights=share_rnn_weights)
+            share_rnn_weights=share_rnn_weights,
+            apply_online=apply_online)
 
     def forward(self, audio, audio_len):
         """export model function

examples/aishell/s0/conf/deepspeech2.yaml

@@ -36,10 +36,11 @@ collator:
 
 model:
   num_conv_layers: 2
-  num_rnn_layers: 3
+  num_rnn_layers: 4
   rnn_layer_size: 1024
   use_gru: True 
   share_rnn_weights: False
+  apply_online: False
 
 training:
   n_epoch: 50

examples/librispeech/s0/conf/deepspeech2.yaml

@@ -40,6 +40,7 @@ model:
   rnn_layer_size: 2048
   use_gru: False 
   share_rnn_weights: True
+  apply_online: False
 
 training:
   n_epoch: 50

examples/tiny/s0/conf/deepspeech2.yaml

@@ -41,6 +41,7 @@ model:
   rnn_layer_size: 2048
   use_gru: False 
   share_rnn_weights: True 
+  apply_online: True
 
 training:
   n_epoch: 10