Files
SIA/sia/local_llm_engine.py
2024-11-14 18:23:33 +01:00

109 lines
3.6 KiB
Python

from threading import Thread
from typing import Iterator, Optional
from transformers import AutoTokenizer, AutoModelForCausalLM, pipeline, TextIteratorStreamer
import torch
from . import util
from .llm_engine import LlmEngine
class LocalLlmEngine(LlmEngine):
def __init__(
self,
model_path: str,
temperature: float,
token_limit: int,
):
"""
Initialize the LLM Engine with a model path.
Args:
model_path: Path to the model weights to be used.
temperature: Temperature for sampling
token_limit: Maximum number of tokens to generate
"""
self._temperature = temperature
self._token_limit = token_limit
self._tokenizer = AutoTokenizer.from_pretrained(model_path)
model = AutoModelForCausalLM.from_pretrained(
model_path,
return_dict=True,
low_cpu_mem_usage=True,
torch_dtype=torch.bfloat16,
device_map="auto",
trust_remote_code=True,
)
if self._tokenizer.pad_token_id is None:
self._tokenizer.pad_token_id = self._tokenizer.eos_token_id
if model.config.pad_token_id is None:
model.config.pad_token_id = model.config.eos_token_id
self._pipeline = pipeline(
"text-generation",
model=model,
tokenizer=self._tokenizer,
torch_dtype=torch.bfloat16,
device_map="auto",
return_full_text=False,
)
def infer(self, system_prompt: str, main_context: str) -> Iterator[str]:
"""
Run inference using the system prompt and main context, while validating actions against the provided XML schema.
Args:
system_prompt: The system prompt string
main_context: The main context string after templating
Returns:
Iterator[str]: An iterator that yields the generated text.
"""
messages = [
{"role": "system", "content": system_prompt},
{"role": "user", "content": main_context}
]
prompt = self._tokenizer.apply_chat_template(
messages, tokenize=False, add_generation_prompt=True
)
streamer = TextIteratorStreamer(
self._tokenizer,
skip_prompt=True
)
pipeline_kwargs = dict(
text_inputs=prompt,
do_sample=True,
temperature=self._temperature,
max_new_tokens=self._token_limit,
streamer=streamer
)
thread = Thread(target=self._pipeline, kwargs=pipeline_kwargs)
thread.start()
return util.stop_before_value(streamer, '<|eot_id|>')
def token_count(self, system_prompt: str, main_context: str) -> int:
"""
Count tokens for the given system prompt and main context.
Args:
system_prompt: The system prompt string
main_context: The main context string
Returns:
int: Total number of tokens
"""
messages = [
{"role": "system", "content": system_prompt},
{"role": "user", "content": main_context}
]
prompt = self._tokenizer.apply_chat_template(
messages, tokenize=False, add_generation_prompt=True
)
return len(self._tokenizer.encode(prompt))
def token_limit(self) -> int:
"""
Get the model's context window size.
Returns:
int: Maximum number of tokens the model can process
"""
return self._pipeline.model.config.max_position_embeddings