505 lines
20 KiB
Python
505 lines
20 KiB
Python
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import logging
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from typing import Any, Dict, Optional, Set, Tuple, Union
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import peft
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import torch
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import torch.nn as nn
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import torch.nn.functional as F
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import transformers
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import transformers.activations
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import transformers.modeling_outputs
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import transformers.models
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# We must use relative import in this directory to allow uploading to HF Hub
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# Even "from . import X" pattern doesn't work (undocumented and unclear why)
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from .ultravox_config import LossConfig
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from .ultravox_config import LossFunction
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from .ultravox_config import UltravoxConfig
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from .whisper_model_modified import WhisperEncoder as ModifiedWhisperEncoder
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class UltravoxModel(transformers.LlamaPreTrainedModel):
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"""
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The Ultravox model which consists of an audio encoder and a language model.
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Audio input is processed by the audio encoder, then every `stack_factor` frames are stacked together and
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projected to the language model's embedding space using a few linear layers.
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The text is embedded by the language model as usual and then the audio and text embeddings are merged together.
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A special token `<|audio|>` is used to indicate the start of the audio embeddings in the merged embeddings.
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Parameters:
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config: Model configuration class with all the parameters of the model.
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"""
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config_class = UltravoxConfig
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config: UltravoxConfig # for type hinting
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_no_split_modules = ["Wav2Vec2Model", "WhisperEncoder", "LlamaDecoderLayer"]
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# We minimize the weights in state_dict in order to reduce the size of the checkpoint
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# The issue is that load_pretrained() uses state_dict() keys to know what keys are expected
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# As such we have to tell is to ignore some keys that are not always in the model
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_keys_to_ignore_on_load_unexpected = ["audio_tower.*", "language_model.*"]
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# Usually we load encoder weights from a pretrained model, so we don't want to load the decoder weights
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# Technically we never hit this issue because these keys are already removed from state_dict() however,
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# but there's no harm in keeping it here for when we change that behavior.
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_keys_to_ignore_on_load_missing = ["audio_tower.*"]
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def __init__(self, config: UltravoxConfig):
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super().__init__(config)
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self.keep_params: Set[str] = set()
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self.vocab_size = config.vocab_size
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self.audio_tower = self._create_audio_tower(config)
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self.multi_modal_projector = UltravoxProjector(config)
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self.language_model = self._create_language_model(config)
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self.loss_config = LossConfig()
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self.post_init()
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def get_input_embeddings(self):
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return self.language_model.get_input_embeddings()
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def set_input_embeddings(self, value):
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self.language_model.set_input_embeddings(value)
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def get_output_embeddings(self):
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return self.language_model.get_output_embeddings()
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def set_output_embeddings(self, new_embeddings):
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self.language_model.set_output_embeddings(new_embeddings)
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def set_decoder(self, decoder):
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self.language_model.set_decoder(decoder)
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def get_decoder(self):
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return self.language_model.get_decoder()
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def tie_weights(self):
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return self.language_model.tie_weights()
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def set_loss_config(self, loss_config: LossConfig):
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self.loss_config = loss_config
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def _setup_cache(
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self, cache_cls, max_batch_size: int, max_cache_len: Optional[int] = None
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):
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self.language_model._setup_cache(cache_cls, max_batch_size, max_cache_len)
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def _reorder_cache(self, past_key_values, beam_idx):
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return self.language_model._reorder_cache(past_key_values, beam_idx)
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def resize_token_embeddings(
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self,
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new_num_tokens: Optional[int] = None,
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pad_to_multiple_of: Optional[int] = None,
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) -> nn.Embedding:
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model_embeds = self.language_model.resize_token_embeddings(
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new_num_tokens, pad_to_multiple_of
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)
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# update vocab size
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self.config.text_config.vocab_size = model_embeds.num_embeddings
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self.config.vocab_size = model_embeds.num_embeddings
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self.vocab_size = model_embeds.num_embeddings
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return model_embeds
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def _compute_kl_loss(
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self,
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lm_output: transformers.modeling_outputs.CausalLMOutputWithPast,
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labels: Optional[torch.Tensor] = None,
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past_key_values: Optional[Union[Tuple, transformers.cache_utils.Cache]] = None,
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alt_input_ids: Optional[torch.Tensor] = None,
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alt_attention_mask: Optional[torch.Tensor] = None,
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alt_labels: Optional[torch.Tensor] = None,
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**kwargs,
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):
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# disable gradient computation for the teacher model
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with torch.no_grad():
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# compute the teacher (text-only) model's distribution
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alt_inputs_embeds = self.get_input_embeddings().forward(alt_input_ids)
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alt_lm_output = self.language_model.forward(
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inputs_embeds=alt_inputs_embeds,
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labels=alt_labels,
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attention_mask=alt_attention_mask,
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past_key_values=past_key_values,
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**kwargs,
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)
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# compute the KL divergence loss between the two models
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kl_loss = F.kl_div(
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F.log_softmax(
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lm_output.logits[labels != -100] / self.loss_config.kl_temperature,
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dim=-1,
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),
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F.softmax(
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alt_lm_output.logits[alt_labels != -100]
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/ self.loss_config.kl_temperature,
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dim=-1,
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),
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reduction="batchmean",
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)
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return {"loss": kl_loss}
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def forward(
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self,
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input_ids: torch.Tensor,
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audio_values: Optional[torch.FloatTensor] = None,
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inputs_embeds: Optional[torch.FloatTensor] = None,
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labels: Optional[torch.Tensor] = None,
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attention_mask: Optional[torch.Tensor] = None,
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audio_token_start_idx: Optional[torch.Tensor] = None,
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audio_token_len: Optional[torch.Tensor] = None,
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past_key_values: Optional[Union[Tuple, transformers.cache_utils.Cache]] = None,
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# the alt_* fields are needed for KL divergence loss
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alt_input_ids: Optional[torch.Tensor] = None,
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alt_attention_mask: Optional[torch.Tensor] = None,
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alt_labels: Optional[torch.Tensor] = None,
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**kwargs,
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) -> Union[Tuple, transformers.modeling_outputs.CausalLMOutputWithPast]:
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"""
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Forward pass for the Ultravox model.
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`input_ids` are the tokenized text input. They are embedded by the language model as usual.
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`audio_values` are processed by the audio encoder and then every `stack_factor` frames are stacked together and
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projected to the language model's embedding space using a few linear layers.
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The audio and text embeddings are merged together. A special token `<|audio|>` is used to indicate the start
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of the audio embeddings in the merged embeddings.
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Args:
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input_ids: The tokenized text input.
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audio_values: The processed audio values.
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inputs_embeds: The embeddings for the input tokens.
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labels: The tokenized text labels.
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attention_mask: The attention mask for the input.
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position_ids: The position ids for the input.
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past_key_values: The past key value cache for the language model attention layers.
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**kwargs: Additional keyword arguments. Passed directly to the language model.
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"""
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if inputs_embeds is None:
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# B x T -> B x T x D
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inputs_embeds = self.get_input_embeddings().forward(input_ids)
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if audio_values is not None:
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assert (
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audio_token_start_idx is not None and audio_token_len is not None
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), "audio_token_start_idx and audio_token_len must be provided if audio_values are provided."
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assert (
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len(audio_token_start_idx) == len(audio_token_len) == len(audio_values)
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), "audio_token_start_idx, audio_token_len, and audio_values must have the same batch size."
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# B x A/3200 x D
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audio_tower_output = self.audio_tower.forward(
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audio_values
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).last_hidden_state
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audio_tower_output = audio_tower_output.to(inputs_embeds.dtype)
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audio_embeds = self.multi_modal_projector.forward(audio_tower_output)
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# combine audio and text embeddings
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for i, (audio, start, length) in enumerate(
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zip(audio_embeds, audio_token_start_idx, audio_token_len)
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):
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length = min(length, audio.shape[0])
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inputs_embeds[i, start : start + length] = audio[:length]
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lm_output = self.language_model.forward(
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inputs_embeds=inputs_embeds,
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labels=labels,
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attention_mask=attention_mask,
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past_key_values=past_key_values,
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**kwargs,
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)
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if self.training:
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if self.loss_config.loss_function == LossFunction.CrossEntropy:
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return lm_output
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elif self.loss_config.loss_function == LossFunction.KL_Divergence:
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return self._compute_kl_loss(
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lm_output=lm_output,
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labels=labels,
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past_key_values=past_key_values,
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alt_input_ids=alt_input_ids,
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alt_attention_mask=alt_attention_mask,
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alt_labels=alt_labels,
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**kwargs,
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)
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else:
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raise ValueError(
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f"Unsupported loss function: {self.loss_config.loss_function}"
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)
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else:
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return lm_output
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def prepare_inputs_for_generation(
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self,
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input_ids: torch.Tensor,
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audio_values: Optional[torch.FloatTensor] = None,
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audio_token_start_idx: Optional[torch.Tensor] = None,
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audio_token_len: Optional[torch.Tensor] = None,
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past_key_values: Optional[Union[Tuple, transformers.cache_utils.Cache]] = None,
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attention_mask: Optional[torch.Tensor] = None,
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inputs_embeds: Optional[torch.Tensor] = None,
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**kwargs,
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) -> Dict[str, Any]:
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model_input = self.language_model.prepare_inputs_for_generation(
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input_ids=input_ids,
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past_key_values=past_key_values,
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attention_mask=attention_mask,
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inputs_embeds=inputs_embeds,
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**kwargs,
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)
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if is_cache_empty(past_key_values) and audio_values is not None:
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# We only want to use audio features in the 1st generation step
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model_input["audio_values"] = audio_values
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model_input["audio_token_start_idx"] = audio_token_start_idx
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model_input["audio_token_len"] = audio_token_len
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return model_input
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@classmethod
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def _create_audio_tower(
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cls, config: UltravoxConfig
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) -> Union[transformers.Wav2Vec2Model, ModifiedWhisperEncoder]:
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if config.audio_model_id is not None:
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if "whisper" in config.audio_model_id is not None:
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audio_tower = ModifiedWhisperEncoder.from_pretrained(
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config.audio_model_id
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)
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else:
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audio_tower = transformers.AutoModel.from_pretrained(
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config.audio_model_id
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)
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else:
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if "whisper" in config.audio_config._name_or_path:
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audio_tower = ModifiedWhisperEncoder(config.audio_config)
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else:
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with transformers.modeling_utils.no_init_weights():
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# we only ever use from_config if the weights are retrained, hence initializing is not
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# required. This makes the model quite creation faster since init on CPU is quite slow.
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audio_tower = transformers.AutoModel.from_config(
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config.audio_config
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)
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if isinstance(
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audio_tower,
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(transformers.Wav2Vec2BertModel, transformers.WhisperModel),
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):
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# For these models we only need the encoder part
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# Wav2Vec2BertModel -> Wav2Vec2BertEncoder
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# WhisperModel -> WhisperEncoder
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audio_tower = audio_tower.encoder
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audio_tower = apply_lora(audio_tower, config.audio_model_lora_config)
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return audio_tower
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@classmethod
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def _create_language_model(
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cls, config: UltravoxConfig
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) -> transformers.LlamaForCausalLM:
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if config.text_model_id is not None:
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language_model = transformers.AutoModelForCausalLM.from_pretrained(
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config.text_model_id, attn_implementation=config._attn_implementation
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)
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else:
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with transformers.modeling_utils.no_init_weights():
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# we only ever use from_config if the weights are retrained, hence initializing is not
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# required. This makes the model quite creation faster since init on CPU is quite slow.
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language_model = transformers.AutoModelForCausalLM.from_config(
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config.text_config, attn_implementation=config._attn_implementation
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)
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language_model = apply_lora(language_model, config.text_model_lora_config)
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return language_model
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def _add_language_model_weights_to_keep(self):
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if self.config.text_model_id is not None:
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self.config.text_model_id = None
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self.keep_params.update(
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set(
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[
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f"language_model.{name}"
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for name, _ in self.language_model.named_parameters()
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]
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)
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)
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def _add_audio_tower_weights_to_keep(self):
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if self.config.audio_model_id is not None:
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self.config.audio_model_id = None
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self.keep_params.update(
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set(
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[
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f"audio_tower.{name}"
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for name, _ in self.audio_tower.named_parameters()
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]
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)
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)
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def merge_and_unload(self):
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if isinstance(self.language_model, peft.PeftModel):
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self.language_model = self.language_model.merge_and_unload()
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# no need to download base language model weights anymore, so we can remove the id
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self._add_language_model_weights_to_keep()
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if isinstance(self.audio_tower, peft.PeftModel):
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self.audio_tower = self.audio_tower.merge_and_unload()
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# no need to download base audio model weights anymore, so we can remove the id
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self._add_audio_tower_weights_to_keep()
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for param in ["text_model_lora_config", "audio_model_lora_config"]:
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if hasattr(self.config, param):
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delattr(self.config, param)
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def push_to_hub(self, *args, **kwargs):
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self.merge_and_unload()
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self.to(self.language_model.dtype)
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return super().push_to_hub(*args, **kwargs)
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def state_dict(self, *args, **kwargs):
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named_params = dict(self.named_parameters())
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state_dict = super().state_dict(*args, **kwargs)
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state_dict = {
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k: v
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for k, v in state_dict.items()
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if k in self.keep_params
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or (k in named_params and named_params[k].requires_grad)
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}
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return state_dict
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def load_state_dict(
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self,
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state_dict: Dict[str, Any],
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*args,
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**kwargs,
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):
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self.keep_params.update(set(state_dict.keys()))
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return super().load_state_dict(state_dict, *args, **kwargs)
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def print_trainable_parameters(self):
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"""
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Prints the number of trainable parameters in the model (reuses Peft model's method)
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"""
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count_params = peft.peft_model.PeftModel.get_nb_trainable_parameters
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trainable_params, all_param = count_params(self)
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logging.info(
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f"trainable params: {trainable_params:,d} || all params: {all_param:,d}"
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f" || trainable%: {100 * trainable_params / all_param:.1f}%"
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)
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lm_trainable_params, lm_all_params = count_params(self.language_model)
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audio_trainable_params, audio_all_params = count_params(self.audio_tower)
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projector_trainable_params = (
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trainable_params - lm_trainable_params - audio_trainable_params
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)
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projector_all_params = all_param - lm_all_params - audio_all_params
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logging.info(
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f"Trainable%: "
|
||
|
f" LLM: {100 * lm_trainable_params / lm_all_params:.1f}%"
|
||
|
f" || Audio Encoder: {100 * audio_trainable_params / audio_all_params:.1f}%"
|
||
|
f" || Projector: {100 * projector_trainable_params / projector_all_params:.1f}%"
|
||
|
)
|
||
|
|
||
|
|
||
|
def is_cache_empty(
|
||
|
past_key_values: Optional[Union[Tuple, transformers.cache_utils.Cache]]
|
||
|
) -> bool:
|
||
|
"""
|
||
|
Check if the cache is empty.
|
||
|
"""
|
||
|
if past_key_values is None:
|
||
|
return True
|
||
|
if isinstance(past_key_values, tuple):
|
||
|
return all(len(c) == 0 for c in past_key_values)
|
||
|
return past_key_values.get_seq_length() == 0
|
||
|
|
||
|
|
||
|
def apply_lora(model: torch.nn.Module, lora_config: dict) -> torch.nn.Module:
|
||
|
"""
|
||
|
Applies LoRA finetuning to the model. If the `r` parameter is set to 0, the model is frozen instead.
|
||
|
"""
|
||
|
lora_config = peft.LoraConfig(**lora_config or {})
|
||
|
|
||
|
if lora_config.r == 0:
|
||
|
# freeze the model entirely
|
||
|
for param in model.parameters():
|
||
|
param.requires_grad = False
|
||
|
else:
|
||
|
model = peft.get_peft_model(model, lora_config)
|
||
|
|
||
|
return model
|
||
|
|
||
|
|
||
|
class StackAudioFrames(nn.Module):
|
||
|
"""
|
||
|
Stack the audio embedding frames to reduce the sequence length by a factor of `stack_factor`.
|
||
|
|
||
|
The number of output frames will be `ceil(T / stack_factor) + 1` where `T` is the number of input frames.
|
||
|
NOTE: the extra +1 is intentional: in case the number of audio tokens are over-estimated by the processor,
|
||
|
we want to make sure `processor.audio_token_replacement` (i.e. EOS) doesn't get leaked into the middle of embeddings.
|
||
|
In most cases this extra padding will get removed in the model's forward function so it has no effect.
|
||
|
"""
|
||
|
|
||
|
def __init__(self, stack_factor: int = 8):
|
||
|
super().__init__()
|
||
|
self.stack_factor = stack_factor
|
||
|
|
||
|
def forward(self, audio_embeds: torch.Tensor) -> torch.Tensor:
|
||
|
B, T, C = audio_embeds.shape
|
||
|
T_pad = (T + self.stack_factor - 1) // self.stack_factor * self.stack_factor
|
||
|
audio_embeds = F.pad(audio_embeds, (0, 0, 0, T_pad - T + self.stack_factor))
|
||
|
B, T, C = audio_embeds.shape
|
||
|
audio_embeds = audio_embeds.view(
|
||
|
B, T // self.stack_factor, C * self.stack_factor
|
||
|
)
|
||
|
return audio_embeds
|
||
|
|
||
|
|
||
|
class RMSNorm(transformers.models.llama.modeling_llama.LlamaRMSNorm):
|
||
|
def __init__(self, hidden_size: int, init: float = 1, eps: float = 1e-6):
|
||
|
super().__init__(hidden_size=hidden_size, eps=eps)
|
||
|
self.weight.data.fill_(init)
|
||
|
|
||
|
|
||
|
class SwiGLU(nn.Module):
|
||
|
def forward(self, x):
|
||
|
x, gate = x.chunk(2, dim=-1)
|
||
|
return F.silu(gate) * x
|
||
|
|
||
|
|
||
|
class UltravoxProjector(nn.Sequential):
|
||
|
def __init__(self, config: UltravoxConfig):
|
||
|
super().__init__()
|
||
|
self.hidden_dim = config.hidden_size
|
||
|
self._pad_and_stack = StackAudioFrames(config.stack_factor)
|
||
|
dim = config.audio_config.hidden_size * config.stack_factor
|
||
|
self.ln_pre = RMSNorm(dim, init=config.norm_init)
|
||
|
self.linear_1 = nn.Linear(dim, self.hidden_dim, bias=False)
|
||
|
dim = self.hidden_dim
|
||
|
self.act = transformers.activations.get_activation(config.projector_act)
|
||
|
dim = dim // 2 if config.projector_act == "swiglu" else dim
|
||
|
self.linear_2 = nn.Linear(dim, config.text_config.hidden_size, bias=False)
|
||
|
self.ln_post = RMSNorm(config.text_config.hidden_size, init=config.norm_init)
|
||
|
|
||
|
def forward(self, audio_features: torch.Tensor) -> torch.Tensor:
|
||
|
audio_features = self._pad_and_stack(audio_features)
|
||
|
audio_features = self.ln_pre(audio_features)
|
||
|
hidden_states = self.linear_1(audio_features)
|
||
|
hidden_states = self.act(hidden_states)
|
||
|
hidden_states = self.linear_2(hidden_states)
|
||
|
hidden_states = self.ln_post(hidden_states)
|
||
|
return hidden_states
|
||
|
|
||
|
|
||
|
UltravoxConfig.register_for_auto_class()
|
||
|
UltravoxModel.register_for_auto_class()
|
||
|
|
||
|
transformers.AutoConfig.register("ultravox", UltravoxConfig)
|
||
|
transformers.AutoModel.register(UltravoxConfig, UltravoxModel)
|
||
|
# transformers.AutoProcessor.register(UltravoxConfig, UltravoxProcessor) # TODO: make processor work standalone
|
||
|
|
||
|
transformers.activations.ACT2FN["swiglu"] = SwiGLU
|