RAG - how to precompute custom document index?
Was wondering if there was any code snippet / blog post showing how one could load their own documents and index them, so they can be used by the RAG retriever.

Cheers!
Second this. 

https://github.com/deepset-ai/haystack may be useful to you. They leverage huggingface and have an DPR implementation with an end-to-end example. Will not be surprised to see RAG implemented soon.
<|||||>@Weilin37 Thanks. I'm also looking at the Faiss docs now (https://github.com/facebookresearch/faiss/wiki/Faiss-indexes).<|||||>@lhoestq can maybe help here as well<|||||>Yep I'm thinking of adding a script in `examples/rag` that shows how to create an indexed dataset for RAG.
I'll let you know how it goes<|||||>@lhoestq Can you please let me know on how we can index the custom datasets? Appreciate your help on this<|||||>@lhoestq I have a bunch of documents to perform Q&A and currently, in the config it says, 
dataset (str, optional, defaults to "wiki_dpr") – A dataset identifier of the indexed dataset on HuggingFace AWS bucket (list all available datasets and ids using datasets.list_datasets()). So how can we create an indexed file and input that to the pretrained model for evaluation. <|||||>> @lhoestq I have a bunch of documents to perform Q&A and currently, in the config it says,
> dataset (str, optional, defaults to "wiki_dpr") – A dataset identifier of the indexed dataset on HuggingFace AWS bucket (list all available datasets and ids using datasets.list_datasets()). So how can we create an indexed file and input that to the pretrained model for evaluation.

Yes right... We'll have to edit the `RagRetriever` and the `HfIndex` to accept custom ones.
If you wanto to give it a try in the meantime, feel free to do so :)<|||||>Any progress on this @lhoestq @patrickvonplaten ? Awesome work guys :)<|||||>@tholor @Timoeller Do you reckon you guys could integrate this work into haystack?<|||||>@aced125 Yep, we will integrate RAG in Haystack soon (https://github.com/deepset-ai/haystack/issues/443).<|||||>> Any progress on this @lhoestq @patrickvonplaten ? Awesome work guys :)

You can expect a PR by tomorrow<|||||>Awesome thanks everyone @tholor @lhoestq @patrickvonplaten !!!!<|||||>Thank you @lhoestq . Really appreciate for getting back quickly on this issue.<|||||>This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
<|||||>Hello everyone,
I am interesting in studying how RAG behaves without the DPR retriever.
For example in the code below

``from transformers import RagRetriever
from transformers import RagTokenizer, RagRetriever, RagTokenForGeneration

retriever = RagRetriever.from_pretrained('./rag-token-nq', indexed_dataset=dataset)
tokenizer = RagTokenizer.from_pretrained("./rag-token-nq")
model = RagTokenForGeneration.from_pretrained("./rag-token-nq", retriever=retriever)

**input_dict = tokenizer.prepare_seq2seq_batch("How many people live in Paris?", "In Paris, there are 10 million people.", return_tensors="pt")**
input_ids = input_dict["input_ids"]

model = RagTokenForGeneration.from_pretrained("facebook/rag-token-nq", retriever=retriever)

generated_ids = model.generate(input_ids=input_ids, labels=input_dict["labels"])

generated_string = tokenizer.batch_decode(generated_ids, skip_special_tokens=True)
print(generated_string) ``

In the line '' **input_dict = tokenizer.prepare_seq2seq_batch("How many people live in Paris?", "In Paris, there are 10 million people.", return_tensors="pt")** ``, I want to use "How many people live in Paris ?" as the question and  "In Paris, there are 10 million people." the passage / context which should be used to generate the answer.

Kindly let me know how to do this?

Is my understanding of the code correct and if not, how to go about it?

Thanks,
Krishanu<|||||>For RAG  you can pass both your question as `input_ids` and your context as `context_input_ids` to `model.generate`.
You can provide several contexts for one question.

You can find more information in the documentation [here](https://huggingface.co/transformers/model_doc/rag.html#transformers.RagTokenForGeneration.generate)<|||||>@lhoestq Thanks for the reply.
There is this doc_score parameter in the model.generate function. Is it necessary or optional?<|||||>If you pass the `context_input_ids` you also need to provide the `doc_scores` indeed.