feat: add the rag example @LongxingTan (#15)

Author: LongxingTan

examples/rag_langchain.py

@@ -1,14 +1,26 @@
+import torch
+import transformers
+from langchain.chains import RetrievalQA
+from langchain.llms import HuggingFacePipeline
 from langchain.retrievers import ContextualCompressionRetriever
 from langchain.text_splitter import RecursiveCharacterTextSplitter
 from langchain_community.document_loaders import PyPDFLoader
 from langchain_community.vectorstores import FAISS
 from langchain_community.vectorstores.utils import DistanceStrategy
+from transformers import AutoModelForCausalLM, AutoTokenizer
+from transformers.generation import GenerationConfig
 
-from retrievals import AutoModelForEmbedding, RerankModel
-from retrievals.tools import LangchainReranker, RagFeature
+from retrievals.tools.langchain import LangchainEmbedding, LangchainReranker, RagFeature
 
-embed_model = AutoModelForEmbedding(model_name_or_path='')
-rerank_model = LangchainReranker(model_name_or_path='', top_n=5, device='cuda')
+
+class CFG:
+    retrieval_model = 'BAAI/bge-large-zh'
+    rerank_model = ''
+    llm_model = 'Qwen/Qwen-7B-Chat'
+
+
+embed_model = LangchainEmbedding(model_name_or_path=CFG.retrieval_model)
+rerank_model = LangchainReranker(model_name_or_path=CFG.rerank_model, top_n=5, device='cuda')
 
 
 documents = PyPDFLoader("llama.pdf").load()
@@ -19,5 +31,30 @@
     search_type="similarity", search_kwargs={"score_threshold": 0.3, "k": 10}
 )
 
-compression_retriever = ContextualCompressionRetriever(base_compressor=rerank_model, base_retriever=retriever)
-response = compression_retriever.get_relevant_documents("What is Llama 2?")
+# compression_retriever = ContextualCompressionRetriever(base_compressor=rerank_model, base_retriever=retriever)
+# response = compression_retriever.get_relevant_documents("What is Llama 2?")
+
+
+tokenizer = AutoTokenizer.from_pretrained(CFG.llm_model, trust_remote_code=True)
+max_memory = f'{int(torch.cuda.mem_get_info()[0]/1024**3)-2}GB'
+n_gpus = torch.cuda.device_count()
+max_memory = {i: max_memory for i in range(n_gpus)}
+model = AutoModelForCausalLM.from_pretrained(
+    CFG.llm_model, device_map='auto', load_in_4bit=True, max_memory=max_memory, trust_remote_code=True, fp16=True
+)
+model = model.eval()
+model.generation_config = GenerationConfig.from_pretrained(CFG.llm_model, trust_remote_code=True)
+
+query_pipeline = transformers.pipeline(
+    "text-generation",
+    model=model,
+    tokenizer=tokenizer,
+    torch_dtype=torch.float16,
+    device_map="auto",
+)
+
+llm = HuggingFacePipeline(pipeline=query_pipeline)
+
+qa = RetrievalQA.from_chain_type(llm=llm, chain_type="stuff", retriever=retriever, verbose=True)
+
+qa.run('你看了这篇文章后有何感性?')

src/retrievals/models/embedding_auto.py

@@ -1,5 +1,5 @@
 import logging
-from typing import Callable, Dict, Iterable, List, Literal, Optional, Tuple, Union
+from typing import Any, Callable, Dict, Iterable, List, Literal, Optional, Tuple, Union
 
 import faiss
 import numpy as np
@@ -60,6 +60,9 @@ class AutoModelForEmbedding(nn.Module):
         from the Hugging Face Hub with that name.
     """
 
+    encode_kwargs: Dict[str, Any] = dict()
+    show_progress: bool = False
+
     def __init__(
         self,
         model_name_or_path: str,
@@ -184,7 +187,17 @@ def forward_from_loader(self, inputs):
             return embeddings
 
     def forward_from_text(self, texts):
-        return self.forward_from_loader(texts)
+        batch_dict = self.tokenizer(
+            texts,
+            max_length=self.max_length,
+            return_attention_mask=False,
+            padding=False,
+            truncation=True,
+        )
+        batch_dict["input_ids"] = [input_ids + [self.tokenizer.eos_token_id] for input_ids in batch_dict["input_ids"]]
+        batch_dict = self.tokenizer.pad(batch_dict, padding=True, return_attention_mask=True, return_tensors="pt")
+        batch_dict.pop("token_type_ids")
+        return self.forward_from_loader(batch_dict)
 
     def encode(
         self,
@@ -197,7 +210,7 @@ def encode(
         device: str = None,
         normalize_embeddings: bool = False,
     ):
-        if isinstance(inputs, DataLoader):
+        if isinstance(inputs, (BatchEncoding, Dict)):
             return self.encode_from_loader(
                 loader=inputs,
                 batch_size=batch_size,
@@ -208,7 +221,7 @@ def encode(
                 device=device,
                 normalize_embeddings=normalize_embeddings,
             )
-        elif isinstance(inputs, (str, Iterable)):
+        elif isinstance(inputs, (str, List, Tuple)):
             return self.encode_from_text(
                 sentences=inputs,
                 batch_size=batch_size,
@@ -219,6 +232,17 @@ def encode(
                 device=device,
                 normalize_embeddings=normalize_embeddings,
             )
+        else:
+            raise ValueError
+
+    def embed_documents(self, texts: List[str]) -> List[List[float]]:
+        """Compute doc embeddings using a HuggingFace transformer model."""
+        embeddings = self.encode(texts, show_progress_bar=self.show_progress, **self.encode_kwargs)
+        return embeddings.tolist()
+
+    def embed_query(self, text: str) -> List[float]:
+        """Compute query embeddings using a HuggingFace transformer model."""
+        return self.embed_documents([text])[0]
 
     def encode_from_loader(
         self,

src/retrievals/models/rag.py

@@ -0,0 +1,46 @@
+from pathlib import Path
+from typing import Any, Callable, Dict, List, Literal, Optional, Tuple, TypeVar, Union
+
+from transformers import AutoModel
+
+
+class RAG(object):
+    def __init__(self):
+        pass
+
+    @classmethod
+    def from_pretrained(
+        cls,
+        model_name_or_path: Union[str, Path],
+        n_gpu: int = -1,
+        verbose: int = 1,
+        index_root: Optional[str] = None,
+    ):
+        instance = cls()
+        instance.model = AutoModel()
+        return instance
+
+    @classmethod
+    def from_index(cls, index_path: Union[str, Path], n_gpu: int = -1, verbose: int = 1):
+        instance = cls()
+        index_path = Path(index_path)
+        instance.model = AutoModel()
+
+        return instance
+
+    def add_to_index(self):
+        return
+
+    def encode(self):
+        return
+
+    def index(self):
+        return
+
+    def search(self):
+        return
+
+
+class Generator(object):
+    def __init__(self):
+        pass

src/retrievals/tools/__init__.py

@@ -1,2 +0,0 @@
-from src.retrievals.tools.langchain import LangchainReranker, RagFeature
-from src.retrievals.tools.llama_index import LlamaIndexReranker

src/retrievals/tools/corpus_processor.py

@@ -0,0 +1,3 @@
+class CorpusProcessor(object):
+    def __init__(self):
+        pass

src/retrievals/tools/langchain.py

@@ -9,11 +9,18 @@
     MarkdownTextSplitter,
 )
 from langchain_core.documents import Document
+from langchain_core.embeddings import Embeddings
 from langchain_core.pydantic_v1 import Extra, root_validator
 
+from src.retrievals.models.embedding_auto import AutoModelForEmbedding
 from src.retrievals.models.rerank import RerankModel
 
 
+class LangchainEmbedding(AutoModelForEmbedding, Embeddings):
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+
+
 class LangchainReranker(BaseDocumentCompressor):
     class Config:
         """Configuration for this pydantic object."""

tests/test_models/test_embedding_auto.py

@@ -149,6 +149,9 @@ def test_encode_from_text(self):
         assert emb.shape == (3, 384)
         # assert abs(np.sum(emb) - 32.14627) < 0.001
 
+    def test_forward_from_text(self):
+        pass
+
 
 class PairwiseModelTest(TestCase, ModelTesterMixin):
     def setUp(self) -> None: