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# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved. | |
# SPDX-License-Identifier: Apache-2.0 | |
# | |
# Licensed under the Apache License, Version 2.0 (the "License"); | |
# you may not use this file except in compliance with the License. | |
# You may obtain a copy of the License at | |
# | |
# http://www.apache.org/licenses/LICENSE-2.0 | |
# | |
# Unless required by applicable law or agreed to in writing, software | |
# distributed under the License is distributed on an "AS IS" BASIS, | |
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
# See the License for the specific language governing permissions and | |
# limitations under the License. | |
from typing import List, Optional, TypedDict | |
import torch | |
from cosmos_predict1.autoregressive.model import AutoRegressiveModel | |
from cosmos_predict1.autoregressive.tokenizer.image_text_tokenizer import ImageTextTokenizer | |
from cosmos_predict1.autoregressive.tokenizer.text_tokenizer import TextTokenizer | |
class ChatPrediction(TypedDict, total=False): | |
tokens: List[str] # not required | |
logprobs: List[float] # not required | |
def chat_completion( | |
model: AutoRegressiveModel, | |
dialogs: List, | |
seed: int = None, | |
temperature: float = 0.01, | |
top_k: int = None, | |
top_p: float = None, | |
max_gen_len: Optional[int] = None, | |
num_gen_seq: int = 1, | |
logprobs: bool = False, | |
generation_prefix: str = "", | |
compile_sampling: bool = False, | |
compile_prefill: bool = False, | |
stop_tokens=None, | |
verbose: bool = False, | |
) -> List[ChatPrediction]: | |
""" | |
Generate assistant responses for a list of conversational dialogs using the language generation model. | |
Args: | |
model (AutoRegressiveModel): The language generation model. | |
dialogs (List): List of conversational dialogs, where each dialog is a list of messages. | |
NOTE if you are using a VLM, all dialogs must either all have images ("image" field) or all be pure text. | |
temperature (float, optional): Temperature value for controlling randomness in sampling. Defaults to 0.01. | |
top_k (int, optional): Top-k probability threshold for nucleus sampling. Defaults to None. If not None, top-p sampling is ignored. | |
top_p (float, optional): Top-p probability threshold for nucleus sampling. Defaults to None. If not None, top-k sampling is ignored. | |
max_gen_len (Optional[int], optional): Maximum length of the generated response sequence. | |
If not provided, it's set to the model's maximum sequence length minus 1. | |
num_gen_seq (int, optional): Number of sequences to generate per prompt. Defaults to 1. | |
logprobs (bool, optional): Flag indicating whether to compute token log probabilities. Defaults to False. | |
generation_prefix (str, optional): Prefix to add before asking model to generate. Helpful to guide the generation. Defaults to "". | |
compile_sampling (bool, optional): Flag indicating whether to compile the generation function. Defaults to False. | |
compile_prefill (bool, optional): Flag indicating whether to compile the prefill function. Defaults to False. | |
stop_tokens (Set[int], optional): Set of tokens to stop generation. Defaults to None. If not None, it will override the model's stop tokens. | |
verbose (bool, optional): Flag indicating whether to print the generation throughput. Defaults to False. | |
Returns: | |
List[ChatPrediction]: List of chat predictions, each containing the assistant's generated response. | |
Note: | |
This method generates assistant responses for the provided conversational dialogs. | |
It employs nucleus sampling to introduce controlled randomness in text generation. | |
If logprobs is True, token log probabilities are computed for each generated token. | |
""" | |
if max_gen_len is None: | |
max_gen_len = model.model.params.max_seq_len - 1 | |
images = None | |
if isinstance(model.tokenizer.text_tokenizer, ImageTextTokenizer): | |
# Vision-language model | |
prompt_dicts = [ | |
model.tokenizer.text_tokenizer.apply_chat_template( | |
dialog, generation_prefix=generation_prefix, add_generation_prompt=True | |
) | |
for dialog in dialogs | |
] | |
prompt_tokens = [prompt_dict["input_ids"] for prompt_dict in prompt_dicts] | |
num_images = sum(["pixel_values" in prompt_dict for prompt_dict in prompt_dicts]) | |
assert num_images in [0, len(dialogs)], "For VLM, all dialogs must either all have images or all be pure text." | |
if num_images > 0: | |
images = torch.cat([prompt_dict["pixel_values"] for prompt_dict in prompt_dicts], dim=0) | |
else: | |
images = None | |
elif isinstance(model.tokenizer.text_tokenizer, TextTokenizer): | |
# Text-only model | |
prompt_tokens = [ | |
model.tokenizer.text_tokenizer.apply_chat_template( | |
dialog, generation_prefix=generation_prefix, add_generation_prompt=True | |
) | |
for dialog in dialogs | |
] | |
else: | |
prompt_tokens = [model.formatter.encode_dialog_prompt(dialog) for dialog in dialogs] | |
generation_tokens, generation_logprobs = model.generate( | |
prompt_tokens=prompt_tokens, | |
seed=seed, | |
max_gen_len=max_gen_len, | |
num_gen_seq=num_gen_seq, | |
temperature=temperature, | |
top_k=top_k, | |
top_p=top_p, | |
compile_sampling=compile_sampling, | |
compile_prefill=compile_prefill, | |
stop_tokens=stop_tokens, | |
verbose=verbose, | |
images=images, | |
) | |
if logprobs: | |
return [ | |
{ | |
"generation": { | |
"role": "assistant", | |
"content": model.tokenizer.text_tokenizer.decode(t), | |
}, | |
"tokens": [model.tokenizer.text_tokenizer.decode([x]) for x in t], | |
"logprobs": logprobs_i, | |
} | |
for t, logprobs_i in zip(generation_tokens, generation_logprobs) | |
] | |
return [ | |
{ | |
"generation": { | |
"role": "assistant", | |
"content": model.tokenizer.text_tokenizer.decode(t), | |
}, | |
} | |
for t in generation_tokens | |
] | |