Fangjun Kuang 5b6699a835
Minor fixes to the RNN-T Conformer model (#152)
* Disable weight decay.

* Remove input feature batchnorm..

* Replace BatchNorm in the Conformer model with LayerNorm.

* Use tanh in the joint network.

* Remove sos ID.

* Reduce the number of decoder layers from 4 to 2.

* Minor fixes.

* Fix typos.
2021-12-23 13:54:25 +08:00

55 lines
1.7 KiB
Python

# Copyright 2021 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.
import torch
import torch.nn as nn
class Joiner(nn.Module):
def __init__(self, input_dim: int, output_dim: int):
super().__init__()
self.output_linear = nn.Linear(input_dim, output_dim)
def forward(
self, encoder_out: torch.Tensor, decoder_out: torch.Tensor
) -> torch.Tensor:
"""
Args:
encoder_out:
Output from the encoder. Its shape is (N, T, C).
decoder_out:
Output from the decoder. Its shape is (N, U, C).
Returns:
Return a tensor of shape (N, T, U, C).
"""
assert encoder_out.ndim == decoder_out.ndim == 3
assert encoder_out.size(0) == decoder_out.size(0)
assert encoder_out.size(2) == decoder_out.size(2)
encoder_out = encoder_out.unsqueeze(2)
# Now encoder_out is (N, T, 1, C)
decoder_out = decoder_out.unsqueeze(1)
# Now decoder_out is (N, 1, U, C)
logit = encoder_out + decoder_out
logit = torch.tanh(logit)
output = self.output_linear(logit)
return output