model.py

from langchain.llms import HuggingFacePipeline
from langchain.embeddings import HuggingFaceInstructEmbeddings
from langchain.chains import RetrievalQA
from transformers import (
    AutoTokenizer,
    AutoModelForSeq2SeqLM,
    pipeline,
    GenerationConfig
)

class lamini:
    def __init__(self):
        pass
    
    def load_model(self, task="text2text-generation", **kwargs) -> HuggingFacePipeline:
        """Returns a pipeline for the model
        - model: MBZUAI/LaMini-Flan-T5-248M
        
        Returns:
            _type_: _description_
        """
        model_id = "MBZUAI/LaMini-Flan-T5-248M"
        tokenizer = AutoTokenizer.from_pretrained(model_id)
        model = AutoModelForSeq2SeqLM.from_pretrained(model_id)
        gen_config = GenerationConfig.from_pretrained(model_id)
        
        max_length = kwargs.get("max_length", 512)
        temperature = kwargs.get("temperature", 0)
        top_p = kwargs.get("top_p", 0.95)
        repetition_penalty = kwargs.get("repetition_penalty", 1.15)
        
        pipe = pipeline( 
                "text2text-generation",
                model=model,
                tokenizer=tokenizer,
                generation_config=gen_config,
                max_length=max_length,
                top_p=top_p,
                temperature=temperature,
                repetition_penalty=repetition_penalty,
        )
        
        llm = HuggingFacePipeline(pipeline=pipe)
        return llm

class templates:
    def __init__(self, llm: HuggingFacePipeline):
        self.llm = llm
    
    def summarize(self, text, **kwargs):
        """Summarize text
        
        Args:
            text (str): text to summarize
        
        Returns:
            str: summarized text
        """
        
        instruction = "summarize for better understanding: "
        text = instruction + text
        return self.llm(text, **kwargs)
    
    def generate_tile(self, text, **kwargs):
        """Generate a title for text
        
        Args:
            text (str): text to generate title for
        
        Returns:
            str: title
        """
        
        instruction = "generate a title for this text: "
        text = instruction + text
        return self.llm(text, **kwargs)

class qa_template:
    def __init__(self, llm):
        from langchain.chains.retrieval_qa.base import BaseRetrievalQA
        self.llm = llm
        self.qa_inf: BaseRetrievalQA
    
    def load(self, knowledge_base):
        """Load knowledge base
        
        Args:
            knowledge_base (str): knowledge base to load
        
        Returns:
            BaseRetrievalQA: (optional to use) returns QA interface
        """
        from utils import LangChainChunker
        from langchain.vectorstores import Chroma
        from langchain.chains import RetrievalQA
        
        embeds = HuggingFaceInstructEmbeddings(model_name="hkunlp/instructor-large")
        chunker = LangChainChunker(knowledge_base)
        chunks = chunker.chunker(size=512)
        db = Chroma.from_texts(chunks, embeds)
        retriever = db.as_retriever()
        
        qa_inf = RetrievalQA.from_chain_type(
            llm=self.llm, chain_type="stuff", retriever=retriever
        )
        
        self.qa_inf = qa_inf
        return qa_inf
    
    def start_gradio(self, title: str):
        """Start gradio interface
        
        Returns:
            _type_: _description_
        """
        import gradio as gr
        
        def interface(msg, history):
            res = self.qa_inf.run(msg)
            return str(res)
        
        ui = gr.ChatInterface(
            fn=interface,
            examples=["What is the video about?", "key points of the video"],
            title=f"Question Mode - {title}",
        )
        
        ui.launch()