predicted masked codebook indexes only

This commit is contained in:
Guo Liyong 2022-05-30 14:33:48 +08:00
parent 0c33543ce7
commit 90024c308f
4 changed files with 67 additions and 22 deletions

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@ -32,7 +32,6 @@ from lhotse.dataset import ( # noqa F401 for PrecomputedFeatures
K2SpeechRecognitionDataset,
PrecomputedFeatures,
SingleCutSampler,
SpecAugment,
)
from lhotse.dataset.input_strategies import ( # noqa F401 For AudioSamples
AudioSamples,
@ -41,6 +40,7 @@ from lhotse.dataset.input_strategies import ( # noqa F401 For AudioSamples
from lhotse.utils import fix_random_seed
from torch.utils.data import DataLoader
from aug import SpecAugment
from icefall.utils import str2bool

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@ -1,6 +1,6 @@
import math
import random
from typing import Dict, Optional
from typing import Dict, Optional, Tuple
import numpy as np
import torch
@ -65,7 +65,7 @@ class SpecAugment(torch.nn.Module):
supervision_segments: Optional[torch.IntTensor] = None,
*args,
**kwargs,
) -> torch.Tensor:
) -> Tuple[torch.Tensor, torch.Tensor]:
"""
Computes SpecAugment for a batch of feature matrices.
@ -87,19 +87,25 @@ class SpecAugment(torch.nn.Module):
"single-channel feature matrices."
)
features = features.clone()
# 1 (True) represents masked area;
# 0 (False) represents original un-masked area.
time_masked_area = torch.zeros_like(features)
if supervision_segments is None:
# No supervisions - apply spec augment to full feature matrices.
for sequence_idx in range(features.size(0)):
features[sequence_idx] = self._forward_single(
features[sequence_idx]
)
(
features[sequence_idx],
time_masked_area[sequence_idx],
) = self._forward_single(features[sequence_idx])
else:
# Supervisions provided - we will apply time warping only on the supervised areas.
for sequence_idx, start_frame, num_frames in supervision_segments:
end_frame = start_frame + num_frames
features[
sequence_idx, start_frame:end_frame
] = self._forward_single(
(
features[sequence_idx, start_frame:end_frame],
time_masked_area[sequence_idx, start_frame:end_frame],
) = self._forward_single(
features[sequence_idx, start_frame:end_frame],
warp=True,
mask=False,
@ -108,27 +114,33 @@ class SpecAugment(torch.nn.Module):
# it might happen that masks are applied to different sequences/examples
# than the time warping.
for sequence_idx in range(features.size(0)):
features[sequence_idx] = self._forward_single(
(
features[sequence_idx],
time_masked_area[sequence_idx],
) = self._forward_single(
features[sequence_idx], warp=False, mask=True
)
return features
return features, time_masked_area
def _forward_single(
self, features: torch.Tensor, warp: bool = True, mask: bool = True
) -> torch.Tensor:
) -> Tuple[torch.Tensor, torch.Tensor]:
"""
Apply SpecAugment to a single feature matrix of shape (T, F).
"""
time_masked_area = torch.zeros_like(features)
if random.random() > self.p:
# Randomly choose whether this transform is applied
return features
# No augmentation, no masked area.
return features, time_masked_area
if warp:
if self.time_warp_factor is not None and self.time_warp_factor >= 1:
features = time_warp(features, factor=self.time_warp_factor)
if mask:
mean = features.mean()
# Frequency masking
features = mask_along_axis_optimized(
features, _ = mask_along_axis_optimized(
features,
mask_size=self.features_mask_size,
mask_times=self.num_feature_masks,
@ -146,7 +158,7 @@ class SpecAugment(torch.nn.Module):
max_mask_frames = min(
self.frames_mask_size, max_tot_mask_frames // num_frame_masks
)
features = mask_along_axis_optimized(
features, time_masked_area = mask_along_axis_optimized(
features,
mask_size=max_mask_frames,
mask_times=num_frame_masks,
@ -154,7 +166,7 @@ class SpecAugment(torch.nn.Module):
axis=1,
)
return features
return features, time_masked_area
def state_dict(self) -> Dict:
return dict(
@ -195,7 +207,7 @@ def mask_along_axis_optimized(
mask_times: int,
mask_value: float,
axis: int,
) -> torch.Tensor:
) -> Tuple[torch.Tensor, torch.Tensor]:
"""
Apply Frequency and Time masking along axis.
Frequency and Time masking as described in the SpecAugment paper.
@ -209,7 +221,11 @@ def mask_along_axis_optimized(
if axis not in [1, 2]:
raise ValueError("Only Frequency and Time masking are supported!")
# 1 (True) represents masked area;
# 0 (False) represents original un-masked area.
masked_area = torch.zeros_like(features)
features = features.unsqueeze(0)
masked_area = masked_area.unsqueeze(0)
features = features.reshape([-1] + list(features.size()[-2:]))
values = torch.randint(int(0), int(mask_size), (1, mask_times))
@ -220,18 +236,22 @@ def mask_along_axis_optimized(
if axis == 1:
if mask_times == 1:
features[:, mask_starts:mask_ends] = mask_value
return features.squeeze(0)
return features.squeeze(0), masked_area
for (mask_start, mask_end) in zip(mask_starts, mask_ends):
features[:, mask_start:mask_end] = mask_value
masked_area[:, mask_start:mask_end] = 1
else:
if mask_times == 1:
features[:, :, mask_starts:mask_ends] = mask_value
return features.squeeze(0)
masked_area[:, :, mask_starts:mask_ends] = 1
return features.squeeze(0), masked_area
for (mask_start, mask_end) in zip(mask_starts, mask_ends):
features[:, :, mask_start:mask_end] = mask_value
masked_area[:, :, mask_start:mask_end] = 1
features = features.squeeze(0)
return features
masked_area = masked_area.squeeze(0)
return features, masked_area
def time_warp(features: torch.Tensor, factor: int) -> torch.Tensor:

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@ -75,7 +75,9 @@ class Transducer(nn.Module):
self.simple_lm_proj = ScaledLinear(decoder_dim, vocab_size)
if num_codebooks > 0:
self.codebook_loss_net = JointCodebookLoss(
predictor_channels=encoder_dim, num_codebooks=num_codebooks
predictor_channels=encoder_dim,
num_codebooks=num_codebooks,
reduction="none",
)
def forward(
@ -88,6 +90,8 @@ class Transducer(nn.Module):
lm_scale: float = 0.0,
warmup: float = 1.0,
codebook_indexes: torch.Tensor = None,
time_masked_area: torch.Tensor = None,
masked_scale: float = 1.0,
) -> torch.Tensor:
"""
Args:
@ -113,6 +117,11 @@ class Transducer(nn.Module):
warmup > 1 "are fully warmed up" and all modules will be active.
codebook_indexes:
codebook_indexes extracted from a teacher model.
time_masked_area:
masked area by SpecAugment, 1 represents masked.
masked_scale:
scale of codebook loss of masked area.
the unmasked_scale = 1 - masked_scale
Returns:
Return the transducer loss.
@ -140,6 +149,21 @@ class Transducer(nn.Module):
codebook_loss = self.codebook_loss_net(
middle_layer_output, codebook_indexes
)
codebook_loss = codebook_loss.reshape(codebook_indexes.shape)
target_t = codebook_loss.shape[1]
time_masked_area = time_masked_area.bool()
time_masked_area = time_masked_area[
:, : target_t * 4 : 4, 0 # noqa E203
]
assert time_masked_area.shape == codebook_loss.shape[:-1]
time_masked_area = time_masked_area.unsqueeze(2).to(
codebook_loss.device
)
masked_loss = (time_masked_area * codebook_loss).sum()
unmasked_loss = (~time_masked_area * codebook_loss).sum()
codebook_loss = (
masked_scale * masked_loss + (1 - masked_scale) * unmasked_loss
)
else:
# when codebook index is not available.
codebook_loss = None

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@ -602,7 +602,7 @@ def compute_loss(
if isinstance(model, DDP)
else next(model.parameters()).device
)
feature = batch["inputs"]
feature, time_masked_area = batch["inputs"]
# at entry, feature is (N, T, C)
assert feature.ndim == 3
feature = feature.to(device)
@ -631,6 +631,7 @@ def compute_loss(
lm_scale=params.lm_scale,
warmup=warmup,
codebook_indexes=codebook_indexes,
time_masked_area=time_masked_area,
)
# after the main warmup step, we keep pruned_loss_scale small
# for the same amount of time (model_warm_step), to avoid