pip install flashrank

pip install flashrank[listwise]

from flashrank import Ranker, RerankRequest

# Nano (~4MB), blazing fast model & competitive performance (ranking precision).

ranker = Ranker(max_length=128)

or 

# Small (~34MB), slightly slower & best performance (ranking precision).
ranker = Ranker(model_name="ms-marco-MiniLM-L-12-v2", cache_dir="/opt")

or 

# Medium (~110MB), slower model with best zeroshot performance (ranking precision) on out of domain data.
ranker = Ranker(model_name="rank-T5-flan", cache_dir="/opt")

or 

# Medium (~150MB), slower model with competitive performance (ranking precision) for 100+ languages  (don't use for english)
ranker = Ranker(model_name="ms-marco-MultiBERT-L-12", cache_dir="/opt")

or 

ranker = Ranker(model_name="rank_zephyr_7b_v1_full", max_length=1024) # adjust max_length based on your passage length

# Metadata is optional, Id can be your DB ids from your retrieval stage or simple numeric indices.
query = "How to speedup LLMs?"
passages = [
   {
      "id":1,
      "text":"Introduce *lookahead decoding*: - a parallel decoding algo to accelerate LLM inference - w/o the need for a draft model or a data store - linearly decreases # decoding steps relative to log(FLOPs) used per decoding step.",
      "meta": {"additional": "info1"}
   },
   {
      "id":2,
      "text":"LLM inference efficiency will be one of the most crucial topics for both industry and academia, simply because the more efficient you are, the more $$$ you will save. vllm project is a must-read for this direction, and now they have just released the paper",
      "meta": {"additional": "info2"}
   },
   {
      "id":3,
      "text":"There are many ways to increase LLM inference throughput (tokens/second) and decrease memory footprint, sometimes at the same time. Here are a few methods I’ve found effective when working with Llama 2. These methods are all well-integrated with Hugging Face. This list is far from exhaustive; some of these techniques can be used in combination with each other and there are plenty of others to try. - Bettertransformer (Optimum Library): Simply call `model.to_bettertransformer()` on your Hugging Face model for a modest improvement in tokens per second. - Fp4 Mixed-Precision (Bitsandbytes): Requires minimal configuration and dramatically reduces the model's memory footprint. - AutoGPTQ: Time-consuming but leads to a much smaller model and faster inference. The quantization is a one-time cost that pays off in the long run.",
      "meta": {"additional": "info3"}

   },
   {
      "id":4,
      "text":"Ever want to make your LLM inference go brrrrr but got stuck at implementing speculative decoding and finding the suitable draft model? No more pain! Thrilled to unveil Medusa, a simple framework that removes the annoying draft model while getting 2x speedup.",
      "meta": {"additional": "info4"}
   },
   {
      "id":5,
      "text":"vLLM is a fast and easy-to-use library for LLM inference and serving. vLLM is fast with: State-of-the-art serving throughput Efficient management of attention key and value memory with PagedAttention Continuous batching of incoming requests Optimized CUDA kernels",
      "meta": {"additional": "info5"}
   }
]

rerankrequest = RerankRequest(query=query, passages=passages)
results = ranker.rerank(rerankrequest)
print(results)

# Reranked output from default reranker
[
   {
      "id":4,
      "text":"Ever want to make your LLM inference go brrrrr but got stuck at implementing speculative decoding and finding the suitable draft model? No more pain! Thrilled to unveil Medusa, a simple framework that removes the annoying draft model while getting 2x speedup.",
      "meta":{
         "additional":"info4"
      },
      "score":0.016847236
   },
   {
      "id":5,
      "text":"vLLM is a fast and easy-to-use library for LLM inference and serving. vLLM is fast with: State-of-the-art serving throughput Efficient management of attention key and value memory with PagedAttention Continuous batching of incoming requests Optimized CUDA kernels",
      "meta":{
         "additional":"info5"
      },
      "score":0.011563735
   },
   {
      "id":3,
      "text":"There are many ways to increase LLM inference throughput (tokens/second) and decrease memory footprint, sometimes at the same time. Here are a few methods I’ve found effective when working with Llama 2. These methods are all well-integrated with Hugging Face. This list is far from exhaustive; some of these techniques can be used in combination with each other and there are plenty of others to try. - Bettertransformer (Optimum Library): Simply call `model.to_bettertransformer()` on your Hugging Face model for a modest improvement in tokens per second. - Fp4 Mixed-Precision (Bitsandbytes): Requires minimal configuration and dramatically reduces the model's memory footprint. - AutoGPTQ: Time-consuming but leads to a much smaller model and faster inference. The quantization is a one-time cost that pays off in the long run.",
      "meta":{
         "additional":"info3"
      },
      "score":0.00081340264
   },
   {
      "id":1,
      "text":"Introduce *lookahead decoding*: - a parallel decoding algo to accelerate LLM inference - w/o the need for a draft model or a data store - linearly decreases # decoding steps relative to log(FLOPs) used per decoding step.",
      "meta":{
         "additional":"info1"
      },
      "score":0.00063596206
   },
   {
      "id":2,
      "text":"LLM inference efficiency will be one of the most crucial topics for both industry and academia, simply because the more efficient you are, the more $$$ you will save. vllm project is a must-read for this direction, and now they have just released the paper",
      "meta":{
         "additional":"info2"
      },
      "score":0.00024851
   }
]

ranker = Ranker(model_name="ms-marco-MiniLM-L-12-v2", cache_dir="/opt")