Minor fixes.

egs/librispeech/ASR/transducer_lstm/encoder.py

@@ -30,13 +30,11 @@ class LstmEncoder(EncoderInterface):
         hidden_size: int,
         output_dim: int,
         subsampling_factor: int = 4,
-        num_encoder_layers: int = 12,
+        num_encoder_layers: int = 6,
         dropout: float = 0.1,
         vgg_frontend: bool = False,
-        proj_size: int = 0,
     ):
         super().__init__()
-        real_hidden_size = proj_size if proj_size > 0 else hidden_size
         assert (
             subsampling_factor == 4
         ), "Only subsampling_factor==4 is supported at present"
@@ -47,28 +45,21 @@ class LstmEncoder(EncoderInterface):
         #   (1) subsampling: T -> T//subsampling_factor
         #   (2) embedding: num_features -> d_model
         if vgg_frontend:
-            self.encoder_embed = VggSubsampling(num_features, real_hidden_size)
+            self.encoder_embed = VggSubsampling(num_features, output_dim)
         else:
-            self.encoder_embed = Conv2dSubsampling(
-                num_features, real_hidden_size
-            )
+            self.encoder_embed = Conv2dSubsampling(num_features, output_dim)
 
         self.rnn = nn.LSTM(
-            input_size=hidden_size,
+            input_size=output_dim,
             hidden_size=hidden_size,
             num_layers=num_encoder_layers,
             bias=True,
-            proj_size=proj_size,
+            proj_size=output_dim,
             batch_first=True,
             dropout=dropout,
             bidirectional=False,
         )
 
-        self.encoder_output_layer = nn.Sequential(
-            nn.Dropout(p=dropout),
-            nn.Linear(real_hidden_size, output_dim),
-        )
-
     def forward(
         self, x: torch.Tensor, x_lens: torch.Tensor
     ) -> Tuple[torch.Tensor, torch.Tensor]:
@@ -96,23 +87,18 @@ class LstmEncoder(EncoderInterface):
             lengths.max(),
         )
 
-        if False:
-            # It is commented out as DPP complains that not all parameters are
-            # used. Need more checks later for the reason.
-            #
-            # Caution: We assume the dataloader returns utterances with
-            # duration being sorted in decreasing order
+        if True:
+            # This branch is more efficient than the else branch
             packed_x = pack_padded_sequence(
                 input=x,
                 lengths=lengths.cpu(),
                 batch_first=True,
-                enforce_sorted=True,
+                enforce_sorted=False,
             )
 
             packed_rnn_out, _ = self.rnn(packed_x)
-            rnn_out, _ = pad_packed_sequence(packed_x, batch_first=True)
+            rnn_out, _ = pad_packed_sequence(packed_rnn_out, batch_first=True)
         else:
             rnn_out, _ = self.rnn(x)
 
-        logits = self.encoder_output_layer(rnn_out)
-        return logits, lengths
+        return rnn_out, lengths

egs/librispeech/ASR/transducer_lstm/test_encoder.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+# Copyright    2022  Xiaomi Corp.        (authors: Fangjun Kuang)
+#
+# See ../../../../LICENSE for clarification regarding multiple authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+"""
+To run this file, do:
+
+    cd icefall/egs/librispeech/ASR
+    python ./transducer_lstm/test_model.py
+"""
+
+import warnings
+
+import torch
+from train import get_encoder_model, get_params
+
+
+def test_encoder_model():
+    params = get_params()
+    params.vocab_size = 500
+    params.blank_id = 0
+    params.context_size = 2
+    encoder = get_encoder_model(params)
+    num_param = sum([p.numel() for p in encoder.parameters()])
+    print(f"Number of encoder model parameters: {num_param}")
+
+    N = 3
+    T = 500
+    C = 80
+
+    x = torch.rand(N, T, C)
+    x_lens = torch.tensor([100, 500, 300])
+
+    y, y_lens = encoder(x, x_lens)
+    print(y.shape)
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore")
+        expected_y_lens = ((x_lens - 1) // 2 - 1) // 2
+
+    assert torch.all(torch.eq(y_lens, expected_y_lens)), (
+        y_lens,
+        expected_y_lens,
+    )
+
+
+def main():
+    test_encoder_model()
+
+
+if __name__ == "__main__":
+    main()

egs/librispeech/ASR/transducer_lstm/test_model.py

@@ -20,7 +20,7 @@
 To run this file, do:
 
     cd icefall/egs/librispeech/ASR
-    python ./pruned_transducer_stateless4/test_model.py
+    python ./transducer_lstm/test_model.py
 """
 
 from train import get_params, get_transducer_model

egs/librispeech/ASR/transducer_lstm/train.py

@@ -42,7 +42,6 @@ export CUDA_VISIBLE_DEVICES="0,1,2,3"
 
 """
 
-
 import argparse
 import logging
 import warnings
@@ -339,9 +338,9 @@ def get_params() -> AttributeDict:
             "feature_dim": 80,
             "subsampling_factor": 4,
             "encoder_dim": 512,
-            "encoder_hidden_size": 1024,
-            "num_encoder_layers": 4,
-            "proj_size": 512,
+            "encoder_hidden_size": 2048,
+            "num_encoder_layers": 6,
+            "dropout": 0.1,
             "vgg_frontend": False,
             # parameters for decoder
             "decoder_dim": 512,
@@ -363,6 +362,7 @@ def get_encoder_model(params: AttributeDict) -> nn.Module:
         output_dim=params.encoder_dim,
         subsampling_factor=params.subsampling_factor,
         num_encoder_layers=params.num_encoder_layers,
+        dropout=params.dropout,
         vgg_frontend=params.vgg_frontend,
     )
     return encoder