yerfor's picture
init
22871e7
from torch import nn
from .espnet_positional_embedding import RelPositionalEncoding
from .espnet_transformer_attn import RelPositionMultiHeadedAttention
from .layers import Swish, ConvolutionModule, EncoderLayer, MultiLayeredConv1d
from ..layers import Embedding
class ConformerLayers(nn.Module):
def __init__(self, hidden_size, num_layers, kernel_size=9, dropout=0.0, num_heads=4,
use_last_norm=True, save_hidden=False):
super().__init__()
self.use_last_norm = use_last_norm
self.layers = nn.ModuleList()
positionwise_layer = MultiLayeredConv1d
positionwise_layer_args = (hidden_size, hidden_size * 4, 1, dropout)
self.pos_embed = RelPositionalEncoding(hidden_size, dropout)
self.encoder_layers = nn.ModuleList([EncoderLayer(
hidden_size,
RelPositionMultiHeadedAttention(num_heads, hidden_size, 0.0),
positionwise_layer(*positionwise_layer_args),
positionwise_layer(*positionwise_layer_args),
ConvolutionModule(hidden_size, kernel_size, Swish()),
dropout,
) for _ in range(num_layers)])
if self.use_last_norm:
self.layer_norm = nn.LayerNorm(hidden_size)
else:
self.layer_norm = nn.Linear(hidden_size, hidden_size)
self.save_hidden = save_hidden
if save_hidden:
self.hiddens = []
def forward(self, x, padding_mask=None):
"""
:param x: [B, T, H]
:param padding_mask: [B, T]
:return: [B, T, H]
"""
self.hiddens = []
nonpadding_mask = x.abs().sum(-1) > 0
x = self.pos_embed(x)
for l in self.encoder_layers:
x, mask = l(x, nonpadding_mask[:, None, :])
if self.save_hidden:
self.hiddens.append(x[0])
x = x[0]
x = self.layer_norm(x) * nonpadding_mask.float()[:, :, None]
return x
class ConformerEncoder(ConformerLayers):
def __init__(self, hidden_size, dict_size, num_layers=None):
conformer_enc_kernel_size = 9
super().__init__(hidden_size, num_layers, conformer_enc_kernel_size)
self.embed = Embedding(dict_size, hidden_size, padding_idx=0)
def forward(self, x):
"""
:param src_tokens: [B, T]
:return: [B x T x C]
"""
x = self.embed(x) # [B, T, H]
x = super(ConformerEncoder, self).forward(x)
return x
class ConformerDecoder(ConformerLayers):
def __init__(self, hidden_size, num_layers):
conformer_dec_kernel_size = 9
super().__init__(hidden_size, num_layers, conformer_dec_kernel_size)