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from threading import Thread
from typing import Iterator
#import torch
from transformers.utils import logging
from ctransformers import AutoModelForCausalLM
from transformers import TextIteratorStreamer, AutoTokenizer
logging.set_verbosity_info()
logger = logging.get_logger("transformers")
config = {"max_new_tokens": 256, "repetition_penalty": 1.1,
"temperature": 0.1, "stream": True}
model_id = "TheBloke/Llama-2-7B-Chat-GGML"
device = "cpu"
model = AutoModelForCausalLM.from_pretrained(model_id, model_type="llama", lib="avx2", hf=True)
tokenizer = AutoTokenizer.from_pretrained("meta-llama/Llama-2-7b-chat-hf")
def get_prompt(message: str, chat_history: list[tuple[str, str]],
system_prompt: str) -> str:
#logger.info("get_prompt chat_history=%s",chat_history)
#logger.info("get_prompt system_prompt=%s",system_prompt)
texts = [f'<s>[INST] <<SYS>>\n{system_prompt}\n<</SYS>>\n\n']
#logger.info("texts=%s",texts)
do_strip = False
for user_input, response in chat_history:
user_input = user_input.strip() if do_strip else user_input
do_strip = True
texts.append(f'{user_input} [/INST] {response.strip()} </s><s>[INST] ')
message = message.strip() if do_strip else message
#logger.info("get_prompt message=%s",message)
texts.append(f'{message} [/INST]')
#logger.info("get_prompt final texts=%s",texts)
return ''.join(texts)
def get_input_token_length(message: str, chat_history: list[tuple[str, str]], system_prompt: str) -> int:
#logger.info("get_input_token_length=%s",message)
prompt = get_prompt(message, chat_history, system_prompt)
#logger.info("prompt=%s",prompt)
input_ids = tokenizer([prompt], return_tensors='np', add_special_tokens=False)['input_ids']
#logger.info("input_ids=%s",input_ids)
return input_ids.shape[-1]
def run(message: str,
chat_history: list[tuple[str, str]],
system_prompt: str,
max_new_tokens: int = 1024,
temperature: float = 0.8,
top_p: float = 0.95,
top_k: int = 50) -> Iterator[str]:
prompt = get_prompt(message, chat_history, system_prompt)
inputs = tokenizer([prompt], return_tensors='pt', add_special_tokens=False).to(device)
streamer = TextIteratorStreamer(tokenizer,
timeout=15.,
skip_prompt=True,
skip_special_tokens=True)
generate_kwargs = dict(
inputs,
streamer=streamer,
max_new_tokens=max_new_tokens,
do_sample=True,
top_p=top_p,
top_k=top_k,
temperature=temperature,
num_beams=1,
)
t = Thread(target=model.generate, kwargs=generate_kwargs)
t.start()
outputs = []
for text in streamer:
outputs.append(text)
yield "".join(outputs)