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2025-07-08 22:18:02 -04:00

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Python

# Copyright (c) Kyutai, all rights reserved.
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
from contextlib import ExitStack
from dataclasses import dataclass, field
from functools import partial
import logging
import typing as tp
import torch
from torch import nn
from ..conditioners import ConditionProvider, ConditionFuser, ConditionTensors
from ..utils.sampling import sample_token
from ..utils.compile import CUDAGraphed
from ..utils.quantize import replace_linear_with_qlinear
from ..modules.streaming import StreamingContainer, StreamingModule, State
from ..modules.transformer import StreamingTransformer, create_norm_fn
from .lm_utils import (_delay_sequence,
_undelay_sequence,
_init_layer,
ScaledEmbedding)
logger = logging.getLogger(__name__)
def scatter_with_mask_(tensor: torch.Tensor, dim: int,
index: torch.Tensor, value: torch.Tensor, mask: torch.Tensor) -> None:
"""Scatter but skipping the updates that are masked."""
old_value = tensor.gather(dim, index)
value = torch.where(mask, value, old_value)
tensor.scatter_(dim, index, value)
@dataclass
class LMOutput:
# The logits are already re-aligned with the input codes
# hence no extra shift is required, e.g. when computing CE
logits: torch.Tensor # [B, K, T, card]
mask: torch.Tensor # [B, K, T]
text_logits: torch.Tensor # [B, 1, T, text_card]
text_mask: torch.Tensor # [B, 1, T]
class LMModel(StreamingContainer):
"""Transformer-based language model on multiple streams of codes.
Args:
n_q (int): Number of parallel streams to model as input.
dep_q (int): Number of parallel streams to model in the depformer.
card (int): Cardinality, vocabulary size.
text_card (int): Cardinality of the text vocabulary.
text_card_out (int or None): Cardinality of output text, if different from the input.
demux_second_text_stream: (bool): Whether two text streams are muxed together with a cartesian product.
dim (int): Dimension of the transformer encoder.
num_heads (int): Number of heads for the transformer encoder.
hidden_scale (int): Scale for hidden feed forward dimension of the transformer encoder.
norm (str): Normalization method.
norm_emb (bool): Whether to normalize embeddings.
bias_proj (bool): Use bias for output projections.
depformer_*: params used for the Depformer Transformer, all the other will be shared.
depformer_multi_linear (bool): if True, uses one linear layer per codebook to project the
output of the main transformer to the Depformer latent space.
depformer_dim_feedforward (int| list[int]| None): If None, defaults to hidden_scale * depformer_dim.
depformer_weights_per_step_schedule (list[int] | None): mapping `CODEBOOK_INDEX -> WEIGHT_INDEX`, allowing
depformer_low_rank_embeddings (int | None): if provided, uses low rank embeddings, with a linear
existing_text_padding_id (int): token to use for the padding.
same_initial (bool): if True, uses the same initial tokens for both text and audio mode.
**kwargs: Additional parameters for the transformer encoder.
"""
def __init__(
self,
delays: tp.List[int] = [0],
n_q: int = 8,
dep_q: int = 8,
card: int = 1024,
text_card: int = 32000,
text_card_out: int | None = None,
demux_second_text_stream: bool = False,
dim: int = 128,
num_heads: int = 8,
hidden_scale: int = 4,
norm: str = "layer_norm",
norm_emb: bool = False,
bias_proj: bool = False,
depformer_dim: int = 256,
depformer_dim_feedforward: int | list[int] | None = None,
depformer_multi_linear: bool = False,
depformer_weights_per_step: bool = False,
depformer_weights_per_step_schedule: list[int] | None = None,
depformer_low_rank_embeddings: int | None = None,
depformer_pos_emb: str = "sin",
existing_text_padding_id: int = 3,
existing_text_end_padding_id: int = 0,
extra_heads_num_heads: int = 0,
extra_heads_dim: int = 6,
context: tp.Optional[int] = None,
causal: bool = True,
condition_provider: tp.Optional[ConditionProvider] = None,
fuser: tp.Optional[ConditionFuser] = None,
quantize: bool = False,
device=None,
dtype=None,
gradient_checkpointing: bool = False,
**kwargs,
):
super().__init__()
self.n_q = n_q
self.dep_q = dep_q
self.card = card
self.text_card = text_card
text_card_out = text_card if text_card_out is None else text_card_out
assert len(delays) == self.num_codebooks, f"expected {self.num_codebooks} delays, got {len(delays)}."
self.delays = delays
self.dim = dim
self.existing_text_padding_id = existing_text_padding_id
self.existing_text_end_padding_id = existing_text_end_padding_id
self.context = context
self.depformer_weights_per_step_schedule = depformer_weights_per_step_schedule
if depformer_weights_per_step_schedule is not None:
assert len(depformer_weights_per_step_schedule) == dep_q
EmbeddingFactory = partial(
ScaledEmbedding,
norm=norm_emb,
device=device,
dtype=dtype,
zero_idx=self.zero_token_id,
)
self.emb = nn.ModuleList(
[EmbeddingFactory(self.card + 1, dim) for _ in range(n_q)]
)
# Unlike for audio, here we authorize the model to output the special token.
self.text_emb = EmbeddingFactory(text_card + 1, dim, demux_second_stream=demux_second_text_stream)
self.text_linear = nn.Linear(dim, text_card_out, bias=bias_proj)
depformer_prefix = "depformer_"
main_kwargs = {
k: v for k, v in kwargs.items() if not k.startswith(depformer_prefix)
}
self.transformer = StreamingTransformer(
d_model=dim,
num_heads=num_heads,
dim_feedforward=int(hidden_scale * dim),
norm=norm,
device=device,
dtype=dtype,
quantize=quantize,
context=context,
causal=causal,
checkpointing=gradient_checkpointing,
**main_kwargs,
)
self.out_norm = create_norm_fn(norm, dim)
self.depformer_multi_linear = depformer_multi_linear
kwargs_dep = main_kwargs.copy()
kwargs_dep.update(
{
k.removeprefix(depformer_prefix): v
for k, v in kwargs.items()
if k.startswith(depformer_prefix)
}
)
kwargs_dep["positional_embedding"] = depformer_pos_emb
kwargs_dep["context"] = None
kwargs_dep["cross_attention"] = False
if depformer_weights_per_step:
kwargs_dep["weights_per_step"] = dep_q
if depformer_multi_linear:
# One linear layer per codebook to project different informations from the main model.
num_in = dep_q
if depformer_weights_per_step_schedule:
num_in = max(depformer_weights_per_step_schedule) + 1
self.depformer_in = nn.ModuleList(
[nn.Linear(dim, depformer_dim, bias=False) for _ in range(num_in)]
)
else:
self.depformer_in = nn.ModuleList(
[nn.Linear(dim, depformer_dim, bias=False)]
)
EmbeddingFactory = partial(EmbeddingFactory, low_rank=depformer_low_rank_embeddings)
if dep_q > 0:
# Only using up to dep_q - 1 because the last codebook is never an input to Depformer.
self.depformer_emb = nn.ModuleList(
[EmbeddingFactory(self.card + 1, depformer_dim) for _ in range(dep_q - 1)]
)
self.depformer_text_emb = EmbeddingFactory(
text_card + 1,
depformer_dim,
demux_second_stream=demux_second_text_stream,
)
if depformer_dim_feedforward is None:
depformer_dim_feedforward = int(hidden_scale * depformer_dim)
self.depformer = StreamingTransformer(
d_model=depformer_dim,
dim_feedforward=depformer_dim_feedforward,
norm=norm,
weights_per_step_schedule=depformer_weights_per_step_schedule,
causal=causal,
quantize=quantize,
checkpointing=gradient_checkpointing,
device=device,
dtype=dtype,
**kwargs_dep,
)
# Depformer follow its own cycle of streaming entirely contained in one time step
# and should not follow the streaming of the steps dimensions.
self.depformer.set_streaming_detached(True)
else: # No-Depformer --- e.g., an ASR model
self.depformer_emb = None
self.depformer_text_emb = None
self.depformer = None
self.extra_heads = nn.ModuleList(
[nn.Linear(dim, extra_heads_dim, bias=False) for _ in range(extra_heads_num_heads)]
)
dim = depformer_dim # we will directly apply the next linears to the output of the Depformer.
self.linears = nn.ModuleList(
[nn.Linear(dim, self.card, bias=bias_proj) for _ in range(dep_q)]
)
self.to(device=device, dtype=dtype)
# We always keep the condition provider as float32.
self.condition_provider = condition_provider
self.fuser = fuser
if self.condition_provider is not None:
self.condition_provider.to(device=device)
if self.fuser is not None:
self.fuser.to(device=device)
self._init_weights()
if quantize:
replace_linear_with_qlinear(self)
@property
def initial_token_id(self) -> int:
"""Token id for the start of sequence (audio)."""
return self.card
@property
def text_initial_token_id(self) -> int:
"""Token id for the start of sequence (text)."""
return self.text_card
@property
def text_padding_token_id(self) -> int:
"""Token id for text padding."""
return self.existing_text_padding_id
@property
def end_of_text_padding_id(self) -> int:
"""Token id for optionally marking the last padding step for a word."""
return self.existing_text_end_padding_id
@property
def zero_token_id(self) -> int:
"""Special value in the input tokens, indicating that no sampling should
happen for that value, and no input should be given to the model."""
return -1
@property
def ungenerated_token_id(self) -> int:
"""Special value that can be provided in the prompt to indicate that this specific
value should be predicted and sampled. This allows for partial teacher forcing, by generating
one modality, with the other one fixed.
"""
return -2
@property
def device(self) -> torch.device:
first_param = next(iter(self.parameters()))
return first_param.device
@property
def dtype(self) -> torch.dtype:
first_param = next(iter(self.text_emb.parameters()))
return first_param.dtype
@property
def num_codebooks(self) -> int:
return self.n_q + 1
@property
def num_audio_codebooks(self) -> int:
return self.n_q
@property
def audio_offset(self) -> int:
return 1
def _get_initial_token(self) -> torch.Tensor:
# Returns the initial token that will be fed to the model to predict the very first timestep.
# The output shape will be [B, K, 1].
device = next(iter(self.parameters())).device
zero = torch.full(
[1, 1, 1], self.zero_token_id, device=device, dtype=torch.long
)
special = torch.full_like(zero, self.initial_token_id)
text_special = torch.full_like(zero, self.text_initial_token_id)
audio_token = special
text_token = text_special
audio_token = audio_token.expand(-1, self.num_audio_codebooks, -1)
token = torch.cat([text_token, audio_token], dim=1)
return token
def forward(
self, codes: torch.Tensor,
condition_tensors: tp.Optional[ConditionTensors] = None) -> LMOutput:
"""Given an input tensor of codes [B, K, T] and list of conditions, returns the logits
along with masks indicating the valid positions at which to compute the loss.
The logits time steps are aligned with those in the input `code`.
Should only be used for training, not inference (use `LMGen` for that).
Args:
codes (torch.Tensor): Input codes of shape [B, K, T] with B the batch size,
K the number of codebooks and T the number of timesteps. When text is supported,
the first 'codebook' corresponds to the text, and the remaining codebooks are for the audio.
condition_tensors (dict[str, ConditionType], optional): pre-computed conditioning tensors.
Returns:
LMOutput: Language model outputs, containing either text or audio logits, or both.
logits (torch.Tensor, or None) of shape [B, K, T, card] corresponding to the provided codes,
i.e. the first item corresponds to logits to predict the first code, meaning that
no additional shifting of codes and logits is required.
mask (torch.Tensor, or None) of shape [B, K, T], mask over valid and invalid positions.
Given the specified interleaving strategies, parts of the logits and codes should
not be considered as valid predictions because of invalid context.
text_logits (torch.Tensor, or None) of shape [B, 1, T, text_card].
text_mask (torch.Tensor, or None) of shape [B, 1, T], mask over the valid positions for the text.
"""
B, K, T = codes.shape
assert K == self.num_codebooks, (K, self.num_codebooks)
# Delaying codes and removing the last time step that will never be an input.
initial = self._get_initial_token().expand(B, -1, -1)
delayed_codes = _delay_sequence(self.delays, codes, initial)
# Inserting the empty tokens for the first time step.
delayed_codes = torch.cat([initial, delayed_codes], dim=2)
sum_condition: torch.Tensor | None = None
cross_attention_src: torch.Tensor | None = None
if condition_tensors is None:
assert self.fuser is None
else:
assert self.fuser is not None
sum_condition = self.fuser.get_sum(condition_tensors)
cross_attention_src = self.fuser.get_cross(condition_tensors)
transformer_out, text_logits = self.forward_text(delayed_codes[:, :, :-1], sum_condition, cross_attention_src)
assert transformer_out.shape[0] == delayed_codes.shape[0]
assert transformer_out.shape[1] == delayed_codes.shape[2] - 1
logits = self.forward_depformer_training(delayed_codes[:, :, 1:], transformer_out)
# map back the logits on pattern sequence to logits on original codes: [B, K, S, card] -> [B, K, T, card]
# and provide the corresponding mask over invalid positions of tokens. We will with NaN values invalid positions
# to ensure they properly handled.
logits, logits_mask = _undelay_sequence(
self.delays[self.audio_offset:self.audio_offset + self.dep_q],
logits, fill_value=float('NaN'))
logits_mask &= (codes[:, self.audio_offset: self.audio_offset + self.dep_q] != self.zero_token_id)
text_logits, text_logits_mask = _undelay_sequence(self.delays[:1], text_logits, fill_value=float('NaN'))
text_logits_mask &= (codes[:, :1] != self.zero_token_id)
return LMOutput(logits, logits_mask, text_logits, text_logits_mask)
def forward_text(
self,
sequence: torch.Tensor, sum_condition: torch.Tensor | None = None,
cross_attention_src: torch.Tensor | None = None,
) -> tuple[torch.Tensor, torch.Tensor]:
B, K, S = sequence.shape
assert (
K == self.num_codebooks
), f"Sequence shape {sequence.shape} must match the number of codebooks."
input_sequence = sequence
input_ = None
for cb_index in range(self.num_audio_codebooks):
audio_emb = self.emb[cb_index](
input_sequence[:, cb_index + self.audio_offset]
)
input_ = audio_emb if input_ is None else input_ + audio_emb
text_emb = self.text_emb(input_sequence[:, 0])
input_ = text_emb if input_ is None else input_ + text_emb
if sum_condition is not None:
input_ = input_ + sum_condition.to(input_)
if cross_attention_src is not None:
cross_attention_src = cross_attention_src.to(input_)
transformer_out = self.transformer(input_, cross_attention_src=cross_attention_src)
if self.out_norm:
transformer_out = self.out_norm(transformer_out)
assert isinstance(transformer_out, torch.Tensor)
text_logits = self.text_linear(transformer_out)
text_logits = text_logits[:, None]
return transformer_out, text_logits
def forward_depformer_training(
self,
sequence: torch.Tensor,
transformer_out: torch.Tensor,
) -> torch.Tensor:
assert self.depformer_text_emb
assert self.depformer_emb
assert self.depformer
B, K, T = sequence.shape
Ka = self.dep_q
assert (
K == self.num_codebooks
), f"Codebooks for Depformer training should be passed all at once, got {K}."
depformer_inputs = []
for cb_index in range(Ka):
if self.depformer_multi_linear:
linear_index = cb_index
if self.depformer_weights_per_step_schedule is not None:
linear_index = self.depformer_weights_per_step_schedule[cb_index]
transformer_in = self.depformer_in[linear_index](transformer_out)
else:
transformer_in = self.depformer_in[0](transformer_out)
if cb_index == 0:
token_in = self.depformer_text_emb(sequence[:, 0])
else:
token_in = self.depformer_emb[cb_index - 1](sequence[:, cb_index + self.audio_offset - 1])
depformer_inputs.append(token_in + transformer_in)
depformer_input = torch.stack(depformer_inputs, 2)
# depformer_input is [B, T, K, depformer_dim], reshaping to [B * T, K, D]
depformer_input = depformer_input.view(B * T, Ka, -1)
depformer_output = self.depformer(depformer_input)
all_logits = []
for cb_index in range(Ka):
logits = self.linears[cb_index](depformer_output[:, cb_index])
all_logits.append(logits.view(B, T, -1))
logits = torch.stack(all_logits, 1)
assert logits.dim() == 4, logits.shape # [B, Ka, T, card]
return logits
def forward_depformer(
self,
depformer_cb_index: int,
sequence: torch.Tensor,
transformer_out: torch.Tensor,
) -> torch.Tensor:
assert self.depformer_text_emb is not None
assert self.depformer_emb is not None
assert self.depformer is not None
B, K, S = sequence.shape
assert (
K == 1
), f"Codebooks for Depformer streaming should be passed 1 by 1, got {K}."
assert (
S == 1
), f"Steps for Depformer streaming should be passed 1 by 1, got {S}."
assert (
transformer_out.shape[1] == 1
), "Transformer out should be a for a single step."
last_token_input: tp.Optional[torch.Tensor] = None
depformer_input = transformer_out
if self.depformer_multi_linear:
in_index = depformer_cb_index
if self.depformer_weights_per_step_schedule is not None:
in_index = self.depformer_weights_per_step_schedule[in_index]
depformer_input = self.depformer_in[in_index](depformer_input)
else:
depformer_input = self.depformer_in[0](depformer_input)
if depformer_cb_index == 0:
last_token_input = self.depformer_text_emb(sequence[:, 0])
else:
last_token_input = self.depformer_emb[depformer_cb_index - 1](
sequence[:, 0]
)
assert last_token_input is not None
depformer_input = depformer_input + last_token_input
assert depformer_input.shape[1] == 1
# depformer_input is [B, 1, depformer_dim].
# The streaming state of the depformer ensures that the proper layer is run.
dep_output = self.depformer(depformer_input)
logits = self.linears[depformer_cb_index](dep_output)
logits = logits[:, None]
assert logits.dim() == 4, logits.shape # [B, Ka, S, card]
return logits
def _init_weights(self):
"""Initialization of the transformer module weights.
Mostly truncated gaussian, with `std = 1 / sqrt(dim_in)`.
Embeddings are also initialized with `1 / sqrt(dim)` rather than `1`.
Some layers are not going to be properly initialized:
- in_proj in MHA.
- depth transformer layers.
This is to match how our models were trained so far.
"""
for emb_layer in self.emb:
_init_layer(emb_layer)
if self.depformer_emb is not None:
for emb_layer in self.depformer_emb:
_init_layer(emb_layer)
_init_layer(self.text_emb)
if self.depformer_text_emb is not None:
_init_layer(self.depformer_text_emb)
_init_layer(self.text_linear)
for tr_layer in self.transformer.layers:
tr_layer.apply(_init_layer)
for linear in self.linears:
_init_layer(linear)
@dataclass
class _LMGenState(State):
cache: torch.Tensor
initial: torch.Tensor
graphed_main: CUDAGraphed
graphed_depth: CUDAGraphed | None
offsets: torch.Tensor
offset_cpu: int = 0
condition_sum: torch.Tensor | None = None
condition_cross: torch.Tensor | None = None
cfg_is_masked_until: torch.Tensor | None = None
exit_stack: ExitStack = field(default_factory=ExitStack)
reset_callback: tp.Callable[[torch.Tensor], None] | None = None
set_exec_mask_callback: tp.Callable[[torch.Tensor], None] | None = None
def reset(self, reset_mask: torch.Tensor) -> None:
super().reset(reset_mask)
self.offsets[:] = torch.where(reset_mask, torch.zeros_like(self.offsets), self.offsets)
self.offset_cpu = 0
if self.reset_callback is not None:
self.reset_callback(reset_mask)
def set_exec_mask(self, exec_mask: torch.Tensor):
super().set_exec_mask(exec_mask)
if self.set_exec_mask_callback is not None:
self.set_exec_mask_callback(exec_mask)
def __enter__(self):
self.exit_stack.__enter__()
def __exit__(self, exc_type, exc_value, traceback):
self.exit_stack.__exit__(exc_type, exc_value, traceback)
class LMGen(StreamingModule[_LMGenState]):
def __init__(
self,
lm_model: LMModel,
use_sampling: bool = True,
temp: float = 0.8,
temp_text: float = 0.7,
top_k: int = 250,
top_k_text: int = 25,
cfg_coef: float = 1.,
check: bool = False,
condition_tensors: ConditionTensors | None = None,
on_text_hook: tp.Optional[tp.Callable[[torch.Tensor], None]] = None,
on_text_logits_hook: tp.Optional[tp.Callable[[torch.Tensor], None]] = None,
on_audio_hook: tp.Optional[tp.Callable[[torch.Tensor], None]] = None,
support_out_of_sync: bool = False,
cfg_is_masked_until: list[int] | None = None,
cfg_is_no_text: bool = False,
):
assert not lm_model.training, "generation shouldn't be used in training mode."
super().__init__()
self.lm_model = lm_model
self.lm_model.set_streaming_detached(True)
self.use_sampling = use_sampling
self.temp = temp
self.temp_text = temp_text
self.top_k = top_k
self.top_k_text = top_k_text
self.cfg_coef = cfg_coef
self.check = check
self.max_delay = max(
lm_model.delays
) # with delays, we need to generate a few more time steps.
self.delays_cuda = torch.tensor(
lm_model.delays, device=lm_model.device, dtype=torch.long
)
self.condition_tensors = condition_tensors
self.on_text_hook = on_text_hook
self.on_text_logits_hook = on_text_logits_hook
self.on_audio_hook = on_audio_hook
self.support_out_of_sync = support_out_of_sync
self.cfg_is_masked_until = cfg_is_masked_until
self.cfg_is_no_text = cfg_is_no_text
if self.cfg_coef != 1.:
if not self.cfg_is_no_text and not self.cfg_is_masked_until:
assert self.lm_model.fuser is not None, "Model has no fuser, cannot do CFG."
assert self.condition_tensors, "Missing condition tensors for CFG."
def _init_streaming_state(self, batch_size: int) -> _LMGenState:
lm_model = self.lm_model
initial = lm_model._get_initial_token()
cache = torch.full(
(batch_size, self.lm_model.num_codebooks, self.max_delay + 2),
lm_model.ungenerated_token_id,
device=lm_model.device,
dtype=torch.long,
)
offsets = torch.zeros(batch_size, device=lm_model.device, dtype=torch.long)
if self.lm_model.fuser is None:
assert not self.condition_tensors
condition_sum = None
condition_cross = None
else:
assert self.condition_tensors is not None
condition_sum = self.lm_model.fuser.get_sum(self.condition_tensors)
condition_cross = self.lm_model.fuser.get_cross(self.condition_tensors)
if condition_sum is not None:
condition_sum = condition_sum.to(self.lm_model.dtype)
if condition_cross is not None:
condition_cross = condition_cross.to(self.lm_model.dtype)
disable = lm_model.device.type != 'cuda'
graphed_main = CUDAGraphed(lm_model.forward_text, disable=disable)
if lm_model.depformer is not None:
graphed_depth = CUDAGraphed(self.depformer_step, disable=disable)
else:
graphed_depth = None
if self.cfg_is_masked_until is None:
cfg_is_masked_until = None
else:
cfg_is_masked_until = torch.tensor(self.cfg_is_masked_until, dtype=torch.long, device=lm_model.device)
state = _LMGenState(
batch_size, lm_model.device, cache, initial, graphed_main, graphed_depth,
offsets, condition_sum=condition_sum, condition_cross=condition_cross,
cfg_is_masked_until=cfg_is_masked_until)
if self.cfg_coef != 1.:
batch_size *= 2
if state.condition_sum is not None:
assert state.condition_sum.shape[0] == batch_size, "cfg requires 2x more conditions."
if state.condition_cross is not None:
assert state.condition_cross.shape[0] == batch_size, "cfg requires 2x more conditions."
state.exit_stack.enter_context(self.lm_model.streaming(batch_size))
def _reset_callback(reset_mask: torch.Tensor) -> None:
if self.cfg_coef != 1.:
reset_mask = reset_mask.repeat(2)
self.lm_model.reset_streaming(reset_mask)
def _set_exec_mask_callback(exec_mask: torch.Tensor) -> None:
if self.cfg_coef != 1.:
exec_mask = exec_mask.repeat(2)
self.lm_model.set_exec_mask(exec_mask)
state.reset_callback = _reset_callback
state.set_exec_mask_callback = _set_exec_mask_callback
return state
@torch.no_grad()
def _step(self, input_tokens: torch.Tensor,
depformer_replace_tokens: torch.Tensor | None = None
) -> tuple[torch.Tensor, torch.Tensor] | None:
state = self._streaming_state
if state is None:
raise RuntimeError(
"You should wrap those calls with a `with lm_gen.streaming(): ...`."
)
lm_model = self.lm_model
assert input_tokens.dim() == 3, "Shape should be [B, K, T]."
B, Ki, S = input_tokens.shape
assert B == state.batch_size, f"Got a batch size {B}, expected {state.batch_size}"
assert S == 1, "Only support being given steps one by one."
needed_tokens = lm_model.num_codebooks - lm_model.dep_q - 1
assert (
Ki >= needed_tokens
), f"We expect {needed_tokens} tokens from the user stream, got {Ki}."
if Ki > needed_tokens:
input_tokens = input_tokens[:, :needed_tokens, :]
CT = state.cache.shape[2]
delays = self.delays_cuda[lm_model.dep_q + 1:]
write_positions = (state.offsets[:, None, None] + delays[:, None]) % CT
scatter_with_mask_(state.cache[:, lm_model.dep_q + 1:], -1, write_positions, input_tokens,
state.exec_mask[:, None, None])
is_init = state.offsets[:, None, None] <= self.delays_cuda[:, None]
is_init |= ~state.exec_mask[:, None, None] # we also give init tokens if not executing to avoid crashing.
positions = (state.offsets % CT)[:, None, None].expand_as(is_init)
input_ = state.cache.gather(dim=2, index=positions)
input_ = torch.where(is_init, state.initial, input_)
if self.check:
# Check that we are not feeding in any value that is not generated yet.
assert not (input_ == lm_model.ungenerated_token_id).any(), (
state.offsets,
input_,
)
assert (input_[:, lm_model.audio_offset :] <= lm_model.card).all(), input_
assert (input_[:, :1] <= lm_model.text_card).all()
zero = torch.full((1,), self.lm_model.zero_token_id, dtype=torch.long, device=input_.device)
if self.cfg_coef != 1.:
if state.cfg_is_masked_until is not None:
limit = self.delays_cuda[:, None] + state.cfg_is_masked_until.view(-1, 1, 1)
is_zeroed = state.offsets[:, None, None] <= limit
masked = torch.where(is_zeroed & ~is_init, zero, input_)
input_ = torch.cat([input_, masked], dim=0)
else:
input_ = input_.repeat(2, 1, 1)
if self.cfg_is_no_text:
input_[B:, :1] = torch.where(~is_init[:, :1], zero, input_[B:, :1])
transformer_out, text_logits = state.graphed_main(input_, state.condition_sum, state.condition_cross)
if self.cfg_coef != 1.:
logits, logits_null = text_logits.chunk(2)
if self.cfg_is_no_text:
text_logits = logits
else:
text_logits = logits_null + (logits - logits_null) * self.cfg_coef
# Shape of text_logits should be [B, K_text=1, T=1, Card_text]
if self.on_text_logits_hook:
self.on_text_logits_hook(text_logits)
text_token = sample_token(
text_logits.float(),
self.use_sampling,
self.temp_text,
self.top_k_text,
)
assert text_token.dim() == 3, text_token.shape
assert text_token.shape[2] == 1
assert text_token.shape[1] == 1, "Only one text stream supported."
text_token = text_token[:, 0, 0] # shape is [B]
if self.on_text_hook is not None:
self.on_text_hook(text_token)
if state.graphed_depth is None:
audio_tokens = None
elif depformer_replace_tokens is None:
audio_tokens = state.graphed_depth(text_token, transformer_out)
if self.on_audio_hook is not None:
self.on_audio_hook(audio_tokens)
else:
assert depformer_replace_tokens.dim() == 3
audio_tokens = depformer_replace_tokens.squeeze(-1)
state.offsets = torch.where(state.exec_mask, state.offsets + 1, state.offsets)
state.offset_cpu += 1
positions = (state.offsets % CT)[:, None, None]
scatter_with_mask_(state.cache[:, :1], -1, positions,
text_token[:, None, None], state.exec_mask[:, None, None])
if audio_tokens is not None:
audio_tokens = audio_tokens[:, :, None]
scatter_with_mask_(
state.cache[:, 1 : lm_model.dep_q + 1, :],
-1,
positions.expand_as(audio_tokens),
audio_tokens,
state.exec_mask[:, None, None],
)
if not self.support_out_of_sync and state.offset_cpu <= self.max_delay:
# When using out of sync exec, should not rely on this being None.
return None
B = state.cache.shape[0]
gen_delays_cuda = self.delays_cuda[: lm_model.dep_q + 1]
index = (state.offsets[:, None, None] - self.max_delay + gen_delays_cuda[:, None]) % CT
out = state.cache.gather(dim=2, index=index)
mask = (state.offsets <= self.max_delay) | ~state.exec_mask
out[mask, :, :] = lm_model.ungenerated_token_id
return out, transformer_out
@torch.no_grad()
def step(self, input_tokens: torch.Tensor,
depformer_replace_tokens: torch.Tensor | None = None) -> torch.Tensor | None:
out = self._step(input_tokens, depformer_replace_tokens)
if out is None:
return None
return out[0]
@torch.no_grad()
def step_with_extra_heads(
self,
input_tokens: torch.Tensor,
depformer_replace_tokens: torch.Tensor | None = None,
) -> tuple[torch.Tensor, list[torch.Tensor]] | None:
out = self._step(input_tokens, depformer_replace_tokens)
if out is None:
return None
out, transformer_out = out
extra_heads = [extra_head(transformer_out) for extra_head in self.lm_model.extra_heads]
return out, extra_heads
def depformer_step(
self,
text_token: torch.Tensor,
transformer_out: torch.Tensor,
) -> torch.Tensor:
B, = text_token.shape
B_cfg = B
if self.cfg_coef != 1.:
B_cfg = 2 * B
prev_token = text_token
lm_model = self.lm_model
depformer_tokens: list[torch.Tensor] = []
assert lm_model.depformer
assert not lm_model.depformer.is_streaming
with lm_model.depformer.streaming(B_cfg):
assert lm_model.depformer.is_streaming
for cb_index in range(lm_model.dep_q):
input_ = prev_token[:, None, None]
if self.cfg_coef != 1.:
input_ = input_.repeat(2, 1, 1)
logits = lm_model.forward_depformer(cb_index, input_, transformer_out)
if self.cfg_coef != 1.:
logits, logits_null = logits.chunk(2)
logits = logits_null + (logits - logits_null) * self.cfg_coef
next_token = sample_token(
logits.float(),
self.use_sampling,
self.temp,
self.top_k,
)
assert next_token.shape == (B, 1, 1)
next_token = next_token[:, 0, 0] # shape is B
depformer_tokens.append(next_token)
prev_token = next_token
assert len(depformer_tokens) == lm_model.dep_q, (
len(depformer_tokens),
lm_model.dep_q,
)
out = torch.stack(depformer_tokens, dim=1)
assert out.shape == (B, lm_model.dep_q), out.shape
return out