# Copyright (c) Facebook, Inc. and its affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
from .fairseq_encoder import FairseqEncoder
[docs]class CompositeEncoder(FairseqEncoder):
"""
A wrapper around a dictionary of :class:`FairseqEncoder` objects.
We run forward on each encoder and return a dictionary of outputs. The first
encoder's dictionary is used for initialization.
Args:
encoders (dict): a dictionary of :class:`FairseqEncoder` objects.
"""
def __init__(self, encoders):
super().__init__(next(iter(encoders.values())).dictionary)
self.encoders = encoders
for key in self.encoders:
self.add_module(key, self.encoders[key])
[docs] def forward(self, src_tokens, src_lengths):
"""
Args:
src_tokens (LongTensor): tokens in the source language of shape
`(batch, src_len)`
src_lengths (LongTensor): lengths of each source sentence of shape
`(batch)`
Returns:
dict:
the outputs from each Encoder
"""
encoder_out = {}
for key in self.encoders:
encoder_out[key] = self.encoders[key](src_tokens, src_lengths)
return encoder_out
[docs] def reorder_encoder_out(self, encoder_out, new_order):
"""Reorder encoder output according to new_order."""
for key in self.encoders:
encoder_out[key] = self.encoders[key].reorder_encoder_out(
encoder_out[key], new_order
)
return encoder_out
[docs] def max_positions(self):
return min(self.encoders[key].max_positions() for key in self.encoders)
def upgrade_state_dict(self, state_dict):
for key in self.encoders:
self.encoders[key].upgrade_state_dict(state_dict)
return state_dict