eli5_utils.py

import functools
import math
import os  # noqa: F401
from random import choice, randint
from time import time

import faiss  # noqa: F401
import nlp  # noqa: F401
import numpy as np
import pandas as pd
import torch
import torch.utils.checkpoint as checkpoint
from elasticsearch import Elasticsearch  # noqa: F401
from elasticsearch.helpers import bulk, streaming_bulk  # noqa: F401
from torch.utils.data import DataLoader, Dataset, RandomSampler, SequentialSampler
from tqdm import tqdm

from transformers import AdamW, AutoModel, AutoModelForSeq2SeqLM, AutoTokenizer, get_linear_schedule_with_warmup


pd.set_option("display.max_colwidth", None)


###############
# Sparse index
###############
def make_es_index_snippets(es_client, passages_dset, index_name="english_wiki_kilt_snippets_100w"):
    index_config = {
        "settings": {
            "number_of_shards": 1,
            "analysis": {"analyzer": {"stop_standard": {"type": "standard", " stopwords": "_english_"}}},
        },
        "mappings": {
            "properties": {
                "article_title": {"type": "text", "analyzer": "standard", "similarity": "BM25"},
                "section_title": {"type": "text", "analyzer": "standard", "similarity": "BM25"},
                "passage_text": {"type": "text", "analyzer": "standard", "similarity": "BM25"},
            }
        },
    }
    es_client.indices.create(index=index_name, body=index_config)
    number_of_docs = passages_dset.num_rows
    progress = tqdm(unit="docs", total=number_of_docs)
    successes = 0

    def passage_generator():
        for passage in passages_dset:
            yield passage

    # create the ES index
    for ok, action in streaming_bulk(client=es_client, index=index_name, actions=passage_generator(),):
        progress.update(1)
        successes += ok
    print("Indexed %d documents" % (successes,))


def query_es_index(question, es_client, index_name="english_wiki_kilt_snippets_100w", n_results=10, min_length=20):
    q = question.lower()
    banned = ["how", "why", "what", "where", "which", "do", "does", "is", "?", "eli5", "eli5:"]
    q = " ".join([w for w in q.split() if w not in banned])
    response = es_client.search(
        index=index_name,
        body={
            "query": {
                "multi_match": {
                    "query": q,
                    "fields": ["article_title", "section_title", "passage_text^2"],
                    "type": "cross_fields",
                }
            },
            "size": 2 * n_results,
        },
    )
    hits = response["hits"]["hits"]
    support_doc = "<P> " + " <P> ".join([hit["_source"]["passage_text"] for hit in hits])
    res_list = [dict([(k, hit["_source"][k]) for k in hit["_source"] if k != "passage_text"]) for hit in hits]
    for r, hit in zip(res_list, hits):
        r["passage_id"] = hit["_id"]
        r["score"] = hit["_score"]
        r["passage_text"] = hit["_source"]["passage_text"]
    res_list = [res for res in res_list if len(res["passage_text"].split()) > min_length][:n_results]
    return support_doc, res_list


###############
# ELI5 retriever training
###############
class ELI5DatasetQARetriver(Dataset):
    def __init__(self, examples_array, extra_answer_threshold=3, min_answer_length=64, training=True, n_samples=None):
        self.data = examples_array
        self.answer_thres = extra_answer_threshold
        self.min_length = min_answer_length
        self.training = training
        self.n_samples = self.data.num_rows if n_samples is None else n_samples

    def __len__(self):
        return self.n_samples

    def make_example(self, idx):
        example = self.data[idx]
        question = example["title"]
        if self.training:
            answers = [a for i, (a, sc) in enumerate(zip(example["answers"]["text"], example["answers"]["score"]))]
            answer_tab = choice(answers).split(" ")
            start_idx = randint(0, max(0, len(answer_tab) - self.min_length))
            answer_span = " ".join(answer_tab[start_idx:])
        else:
            answer_span = example["answers"]["text"][0]
        return (question, answer_span)

    def __getitem__(self, idx):
        return self.make_example(idx % self.data.num_rows)


class RetrievalQAEmbedder(torch.nn.Module):
    def __init__(self, sent_encoder, dim):
        super(RetrievalQAEmbedder, self).__init__()
        self.sent_encoder = sent_encoder
        self.output_dim = 128
        self.project_q = torch.nn.Linear(dim, self.output_dim, bias=False)
        self.project_a = torch.nn.Linear(dim, self.output_dim, bias=False)
        self.ce_loss = torch.nn.CrossEntropyLoss(reduction="mean")

    def embed_sentences_checkpointed(self, input_ids, attention_mask, checkpoint_batch_size=-1):
        # reproduces BERT forward pass with checkpointing
        if checkpoint_batch_size < 0 or input_ids.shape[0] < checkpoint_batch_size:
            return self.sent_encoder(input_ids, attention_mask=attention_mask)[1]
        else:
            # prepare implicit variables
            device = input_ids.device
            input_shape = input_ids.size()
            token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=device)
            head_mask = [None] * self.sent_encoder.config.num_hidden_layers
            extended_attention_mask: torch.Tensor = self.sent_encoder.get_extended_attention_mask(
                attention_mask, input_shape, device
            )

            # define function for checkpointing
            def partial_encode(*inputs):
                encoder_outputs = self.sent_encoder.encoder(inputs[0], attention_mask=inputs[1], head_mask=head_mask,)
                sequence_output = encoder_outputs[0]
                pooled_output = self.sent_encoder.pooler(sequence_output)
                return pooled_output

            # run embedding layer on everything at once
            embedding_output = self.sent_encoder.embeddings(
                input_ids=input_ids, position_ids=None, token_type_ids=token_type_ids, inputs_embeds=None
            )
            # run encoding and pooling on one mini-batch at a time
            pooled_output_list = []
            for b in range(math.ceil(input_ids.shape[0] / checkpoint_batch_size)):
                b_embedding_output = embedding_output[b * checkpoint_batch_size : (b + 1) * checkpoint_batch_size]
                b_attention_mask = extended_attention_mask[b * checkpoint_batch_size : (b + 1) * checkpoint_batch_size]
                pooled_output = checkpoint.checkpoint(partial_encode, b_embedding_output, b_attention_mask)
                pooled_output_list.append(pooled_output)
            return torch.cat(pooled_output_list, dim=0)

    def embed_questions(self, q_ids, q_mask, checkpoint_batch_size=-1):
        q_reps = self.embed_sentences_checkpointed(q_ids, q_mask, checkpoint_batch_size)
        return self.project_q(q_reps)

    def embed_answers(self, a_ids, a_mask, checkpoint_batch_size=-1):
        a_reps = self.embed_sentences_checkpointed(a_ids, a_mask, checkpoint_batch_size)
        return self.project_a(a_reps)

    def forward(self, q_ids, q_mask, a_ids, a_mask, checkpoint_batch_size=-1):
        device = q_ids.device
        q_reps = self.embed_questions(q_ids, q_mask, checkpoint_batch_size)
        a_reps = self.embed_answers(a_ids, a_mask, checkpoint_batch_size)
        compare_scores = torch.mm(q_reps, a_reps.t())
        loss_qa = self.ce_loss(compare_scores, torch.arange(compare_scores.shape[1]).to(device))
        loss_aq = self.ce_loss(compare_scores.t(), torch.arange(compare_scores.shape[0]).to(device))
        loss = (loss_qa + loss_aq) / 2
        return loss


def make_qa_retriever_model(model_name="google/bert_uncased_L-8_H-512_A-8", from_file=None, device="cuda:0"):
    tokenizer = AutoTokenizer.from_pretrained(model_name)
    bert_model = AutoModel.from_pretrained(model_name).to(device)
    # run bert_model on a dummy batch to get output dimension
    d_ids = torch.LongTensor(
        [[bert_model.config.bos_token_id if bert_model.config.bos_token_id is not None else 1]]
    ).to(device)
    d_mask = torch.LongTensor([[1]]).to(device)
    sent_dim = bert_model(d_ids, attention_mask=d_mask)[1].shape[-1]
    qa_embedder = RetrievalQAEmbedder(bert_model, sent_dim).to(device)
    if from_file is not None:
        param_dict = torch.load(from_file)  # has model weights, optimizer, and scheduler states
        qa_embedder.load_state_dict(param_dict["model"])
    return tokenizer, qa_embedder


def make_qa_retriever_batch(qa_list, tokenizer, max_len=64, device="cuda:0"):
    q_ls = [q for q, a in qa_list]
    a_ls = [a for q, a in qa_list]
    q_toks = tokenizer(q_ls, max_length=max_len, padding="max_length", truncation=True)
    q_ids, q_mask = (
        torch.LongTensor(q_toks["input_ids"]).to(device),
        torch.LongTensor(q_toks["attention_mask"]).to(device),
    )
    a_toks = tokenizer(a_ls, max_length=max_len, padding="max_length", truncation=True)
    a_ids, a_mask = (
        torch.LongTensor(a_toks["input_ids"]).to(device),
        torch.LongTensor(a_toks["attention_mask"]).to(device),
    )
    return (q_ids, q_mask, a_ids, a_mask)


def train_qa_retriever_epoch(model, dataset, tokenizer, optimizer, scheduler, args, e=0):
    model.train()
    # make iterator
    train_sampler = RandomSampler(dataset)
    model_collate_fn = functools.partial(
        make_qa_retriever_batch, tokenizer=tokenizer, max_len=args.max_length, device="cuda:0"
    )
    data_loader = DataLoader(dataset, batch_size=args.batch_size, sampler=train_sampler, collate_fn=model_collate_fn)
    epoch_iterator = tqdm(data_loader, desc="Iteration", disable=True)
    # accumulate loss since last print
    loc_steps = 0
    loc_loss = 0.0
    st_time = time()
    for step, batch in enumerate(epoch_iterator):
        q_ids, q_mask, a_ids, a_mask = batch
        pre_loss = model(q_ids, q_mask, a_ids, a_mask, checkpoint_batch_size=args.checkpoint_batch_size)
        loss = pre_loss.sum()
        # optimizer
        loss.backward()
        optimizer.step()
        scheduler.step()
        model.zero_grad()
        # some printing within the epoch
        loc_loss += loss.item()
        loc_steps += 1
        if step % args.print_freq == 0 or step == 1:
            print(
                "{:2d} {:5d} of {:5d} \t L: {:.3f} \t -- {:.3f}".format(
                    e, step, len(dataset) // args.batch_size, loc_loss / loc_steps, time() - st_time,
                )
            )
            loc_loss = 0
            loc_steps = 0


def train_qa_retriever_joint_epoch(model, dataset_list, tokenizer, optimizer, scheduler, args, e=0):
    model.train()
    model_collate_fn = functools.partial(
        make_qa_retriever_batch, tokenizer=tokenizer, max_len=args.max_length, device="cuda:0"
    )
    # make iterator
    train_samplers = [RandomSampler(dataset) for dataset in dataset_list]
    data_loaders = [
        DataLoader(dataset, batch_size=args.batch_size, sampler=train_sampler, collate_fn=model_collate_fn)
        for dataset, train_sampler in zip(dataset_list, train_samplers)
    ]
    iterators = [iter(dloader) for dloader in data_loaders]
    joint_iter = zip(*iterators)
    # accumulate loss since last print
    loc_steps = 0
    loc_loss = 0.0
    st_time = time()
    for step, (batches,) in enumerate(zip(joint_iter)):
        for batch in batches:
            q_ids, q_mask, a_ids, a_mask = batch
            loss = model(q_ids, q_mask, a_ids, a_mask, checkpoint_batch_size=args.checkpoint_batch_size)
            # optimizer
            loss.backward()
            optimizer.step()
            scheduler.step()
            model.zero_grad()
            # some printing within the epoch
            loc_loss += loss.item()
            loc_steps += 1
        if step % args.print_freq == 0:
            print(
                "{:2d} {:5d} of {:5d} \t L: {:.3f} \t -- {:.3f}".format(
                    e, step, len(dataset_list[0]) // args.batch_size, loc_loss / loc_steps, time() - st_time,
                )
            )
            loc_loss = 0
            loc_steps = 0


def evaluate_qa_retriever(model, dataset, tokenizer, args):
    model.eval()
    # make iterator
    eval_sampler = SequentialSampler(dataset)
    model_collate_fn = functools.partial(
        make_qa_retriever_batch, tokenizer=tokenizer, max_len=args.max_length, device="cuda:0"
    )
    data_loader = DataLoader(dataset, batch_size=args.batch_size, sampler=eval_sampler, collate_fn=model_collate_fn)
    epoch_iterator = tqdm(data_loader, desc="Iteration", disable=True)
    tot_loss = 0.0
    with torch.no_grad():
        for step, batch in enumerate(epoch_iterator):
            q_ids, q_mask, a_ids, a_mask = batch
            loss = model(q_ids, q_mask, a_ids, a_mask)
            tot_loss += loss.item()
        return tot_loss / (step + 1)


def train_qa_retriever(qar_model, qar_tokenizer, qar_train_dset, qar_valid_dset, qar_args):
    qar_optimizer = AdamW(qar_model.parameters(), lr=qar_args.learning_rate, eps=1e-8)
    qar_scheduler = get_linear_schedule_with_warmup(
        qar_optimizer,
        num_warmup_steps=100,
        num_training_steps=(qar_args.num_epochs + 1) * math.ceil(len(qar_train_dset) / qar_args.batch_size),
    )
    for e in range(qar_args.num_epochs):
        train_qa_retriever_epoch(qar_model, qar_train_dset, qar_tokenizer, qar_optimizer, qar_scheduler, qar_args, e)
        m_save_dict = {
            "model": qar_model.state_dict(),
            "optimizer": qar_optimizer.state_dict(),
            "scheduler": qar_scheduler.state_dict(),
        }
        print("Saving model {}".format(qar_args.model_save_name))
        torch.save(m_save_dict, "{}_{}.pth".format(qar_args.model_save_name, e))
        eval_loss = evaluate_qa_retriever(qar_model, qar_valid_dset, qar_tokenizer, qar_args)
        print("Evaluation loss epoch {:4d}: {:.3f}".format(e, eval_loss))


###############
# ELI5 seq2seq model training
###############
class ELI5DatasetS2S(Dataset):
    def __init__(
        self, examples_array, make_doc_fun=None, extra_answer_threshold=3, document_cache=None, training=True
    ):
        self.training = training
        self.data = examples_array
        self.make_doc_function = make_doc_fun
        self.document_cache = {} if document_cache is None else document_cache
        assert not (make_doc_fun is None and document_cache is None)
        # make index of specific question-answer pairs from multi-answers
        if self.training:
            self.qa_id_list = [
                (i, j)
                for i, qa in enumerate(self.data)
                for j, (a, sc) in enumerate(zip(qa["answers"]["text"], qa["answers"]["score"]))
                if j == 0 or sc >= extra_answer_threshold
            ]
        else:
            self.qa_id_list = [(i, 0) for i in range(self.data.num_rows)]

    def __len__(self):
        return len(self.qa_id_list)

    def make_example(self, idx):
        i, j = self.qa_id_list[idx]
        example = self.data[i]
        question = example["title"] + " " + example["selftext"]
        answer = example["answers"]["text"][j]
        q_id = example["q_id"]
        if self.make_doc_function is not None:
            self.document_cache[q_id] = self.document_cache.get(q_id, self.make_doc_function(example["title"]))
        document = self.document_cache[q_id]
        in_st = "question: {} context: {}".format(
            question.lower().replace(" --t--", "").strip(), document.lower().strip(),
        )
        out_st = answer
        return (in_st, out_st)

    def __getitem__(self, idx):
        return self.make_example(idx)


def make_qa_s2s_model(model_name="facebook/bart-large", from_file=None, device="cuda:0"):
    tokenizer = AutoTokenizer.from_pretrained(model_name)
    model = AutoModelForSeq2SeqLM.from_pretrained(model_name).to(device)
    if from_file is not None:
        param_dict = torch.load(from_file)  # has model weights, optimizer, and scheduler states
        model.load_state_dict(param_dict["model"])
    return tokenizer, model


def make_qa_s2s_batch(qa_list, tokenizer, max_len=64, max_a_len=360, device="cuda:0"):
    q_ls = [q for q, a in qa_list]
    a_ls = [a for q, a in qa_list]
    q_toks = tokenizer(q_ls, max_length=max_len, padding="max_length", truncation=True)
    q_ids, q_mask = (
        torch.LongTensor(q_toks["input_ids"]).to(device),
        torch.LongTensor(q_toks["attention_mask"]).to(device),
    )
    a_toks = tokenizer(a_ls, max_length=min(max_len, max_a_len), padding="max_length", truncation=True)
    a_ids, a_mask = (
        torch.LongTensor(a_toks["input_ids"]).to(device),
        torch.LongTensor(a_toks["attention_mask"]).to(device),
    )
    lm_labels = a_ids[:, 1:].contiguous().clone()
    lm_labels[a_mask[:, 1:].contiguous() == 0] = -100
    model_inputs = {
        "input_ids": q_ids,
        "attention_mask": q_mask,
        "decoder_input_ids": a_ids[:, :-1].contiguous(),
        "lm_labels": lm_labels,
    }
    return model_inputs


def train_qa_s2s_epoch(model, dataset, tokenizer, optimizer, scheduler, args, e=0, curriculum=False):
    model.train()
    # make iterator
    if curriculum:
        train_sampler = SequentialSampler(dataset)
    else:
        train_sampler = RandomSampler(dataset)
    model_collate_fn = functools.partial(
        make_qa_s2s_batch, tokenizer=tokenizer, max_len=args.max_length, device="cuda:0"
    )
    data_loader = DataLoader(dataset, batch_size=args.batch_size, sampler=train_sampler, collate_fn=model_collate_fn)
    epoch_iterator = tqdm(data_loader, desc="Iteration", disable=True)
    # accumulate loss since last print
    loc_steps = 0
    loc_loss = 0.0
    st_time = time()
    for step, batch_inputs in enumerate(epoch_iterator):
        pre_loss = model(**batch_inputs)[0]
        loss = pre_loss.sum() / pre_loss.shape[0]
        loss.backward()
        # optimizer
        if step % args.backward_freq == 0:
            optimizer.step()
            scheduler.step()
            model.zero_grad()
        # some printing within the epoch
        loc_loss += loss.item()
        loc_steps += 1
        if step % args.print_freq == 0 or step == 1:
            print(
                "{:2d} {:5d} of {:5d} \t L: {:.3f} \t -- {:.3f}".format(
                    e, step, len(dataset) // args.batch_size, loc_loss / loc_steps, time() - st_time,
                )
            )
            loc_loss = 0
            loc_steps = 0


def eval_qa_s2s_epoch(model, dataset, tokenizer, args):
    model.eval()
    # make iterator
    train_sampler = SequentialSampler(dataset)
    model_collate_fn = functools.partial(
        make_qa_s2s_batch, tokenizer=tokenizer, max_len=args.max_length, device="cuda:0"
    )
    data_loader = DataLoader(dataset, batch_size=args.batch_size, sampler=train_sampler, collate_fn=model_collate_fn)
    epoch_iterator = tqdm(data_loader, desc="Iteration", disable=True)
    # accumulate loss since last print
    loc_steps = 0
    loc_loss = 0.0
    st_time = time()
    with torch.no_grad():
        for step, batch_inputs in enumerate(epoch_iterator):
            pre_loss = model(**batch_inputs)[0]
            loss = pre_loss.sum() / pre_loss.shape[0]
            loc_loss += loss.item()
            loc_steps += 1
            if step % args.print_freq == 0:
                print(
                    "{:5d} of {:5d} \t L: {:.3f} \t -- {:.3f}".format(
                        step, len(dataset) // args.batch_size, loc_loss / loc_steps, time() - st_time,
                    )
                )
    print("Total \t L: {:.3f} \t -- {:.3f}".format(loc_loss / loc_steps, time() - st_time,))


def train_qa_s2s(qa_s2s_model, qa_s2s_tokenizer, s2s_train_dset, s2s_valid_dset, s2s_args):
    s2s_optimizer = AdamW(qa_s2s_model.parameters(), lr=s2s_args.learning_rate, eps=1e-8)
    s2s_scheduler = get_linear_schedule_with_warmup(
        s2s_optimizer,
        num_warmup_steps=400,
        num_training_steps=(s2s_args.num_epochs + 1) * math.ceil(len(s2s_train_dset) / s2s_args.batch_size),
    )
    for e in range(s2s_args.num_epochs):
        train_qa_s2s_epoch(
            qa_s2s_model,
            s2s_train_dset,
            qa_s2s_tokenizer,
            s2s_optimizer,
            s2s_scheduler,
            s2s_args,
            e,
            curriculum=(e == 0),
        )
        m_save_dict = {
            "model": qa_s2s_model.state_dict(),
            "optimizer": s2s_optimizer.state_dict(),
            "scheduler": s2s_scheduler.state_dict(),
        }
        print("Saving model {}".format(s2s_args.model_save_name))
        eval_qa_s2s_epoch(qa_s2s_model, s2s_valid_dset, qa_s2s_tokenizer, s2s_args)
        torch.save(m_save_dict, "{}_{}.pth".format(s2s_args.model_save_name, e))


# generate answer from input "question: ... context: <p> ..."
def qa_s2s_generate(
    question_doc,
    qa_s2s_model,
    qa_s2s_tokenizer,
    num_answers=1,
    num_beams=None,
    min_len=64,
    max_len=256,
    do_sample=False,
    temp=1.0,
    top_p=None,
    top_k=None,
    max_input_length=512,
    device="cuda:0",
):
    model_inputs = make_qa_s2s_batch([(question_doc, "A")], qa_s2s_tokenizer, max_input_length, device=device,)
    n_beams = num_answers if num_beams is None else max(num_beams, num_answers)
    generated_ids = qa_s2s_model.generate(
        input_ids=model_inputs["input_ids"],
        attention_mask=model_inputs["attention_mask"],
        min_length=min_len,
        max_length=max_len,
        do_sample=do_sample,
        early_stopping=True,
        num_beams=1 if do_sample else n_beams,
        temperature=temp,
        top_k=top_k,
        top_p=top_p,
        eos_token_id=qa_s2s_tokenizer.eos_token_id,
        no_repeat_ngram_size=3,
        num_return_sequences=num_answers,
        decoder_start_token_id=qa_s2s_tokenizer.bos_token_id,
    )
    return [qa_s2s_tokenizer.decode(ans_ids, skip_special_tokens=True).strip() for ans_ids in generated_ids]


###############
# ELI5-trained retrieval model usage
###############
def embed_passages_for_retrieval(passages, tokenizer, qa_embedder, max_length=128, device="cuda:0"):
    a_toks = tokenizer(passages, max_length=max_length, padding="max_length", truncation=True)
    a_ids, a_mask = (
        torch.LongTensor(a_toks["input_ids"]).to(device),
        torch.LongTensor(a_toks["attention_mask"]).to(device),
    )
    with torch.no_grad():
        a_reps = qa_embedder.embed_answers(a_ids, a_mask).cpu().type(torch.float)
    return a_reps.numpy()


def embed_questions_for_retrieval(q_ls, tokenizer, qa_embedder, device="cuda:0"):
    q_toks = tokenizer(q_ls, max_length=128, padding="max_length", truncation=True)
    q_ids, q_mask = (
        torch.LongTensor(q_toks["input_ids"]).to(device),
        torch.LongTensor(q_toks["attention_mask"]).to(device),
    )
    with torch.no_grad():
        q_reps = qa_embedder.embed_questions(q_ids, q_mask).cpu().type(torch.float)
    return q_reps.numpy()


def make_qa_dense_index(
    qa_embedder,
    tokenizer,
    passages_dset,
    batch_size=512,
    max_length=128,
    index_name="kilt_passages_reps.dat",
    dtype="float32",
    device="cuda:0",
):
    st_time = time()
    fp = np.memmap(index_name, dtype=dtype, mode="w+", shape=(passages_dset.num_rows, 128))
    n_batches = math.ceil(passages_dset.num_rows / batch_size)
    for i in range(n_batches):
        passages = [p for p in passages_dset[i * batch_size : (i + 1) * batch_size]["passage_text"]]
        reps = embed_passages_for_retrieval(passages, tokenizer, qa_embedder, max_length, device)
        fp[i * batch_size : (i + 1) * batch_size] = reps
        if i % 50 == 0:
            print(i, time() - st_time)


def evaluate_retriever(qa_list, retriever_func, scoring_func, n_ret=10, verbose=False):
    total_retriever_time = 0.0
    total_retriever_score = 0.0
    st_time = time()
    for i, (question, answer) in enumerate(qa_list):
        r_time = time()
        retrieved_passages = retriever_func(question, n_ret)
        total_retriever_time += time() - r_time
        total_retriever_score += scoring_func(retrieved_passages, answer)
        if verbose and ((i + 1) % 500 == 0 or i <= 1):
            print(
                "{:03d}: S-{:.4f} T-{:.4f} | {:.2f}".format(
                    i + 1, total_retriever_score / (i + 1), total_retriever_time / (i + 1), time() - st_time
                )
            )
    return {"idf_recall": total_retriever_score / (i + 1), "retrieval_time": total_retriever_time / (i + 1)}


# build a support document for the question out of Wikipedia snippets
def query_qa_dense_index(
    question, qa_embedder, tokenizer, wiki_passages, wiki_index, n_results=10, min_length=20, device="cuda:0"
):
    q_rep = embed_questions_for_retrieval([question], tokenizer, qa_embedder, device=device)
    D, I = wiki_index.search(q_rep, 2 * n_results)
    res_passages = [wiki_passages[int(i)] for i in I[0]]
    support_doc = "<P> " + " <P> ".join([p["passage_text"] for p in res_passages])
    res_list = [dict([(k, p[k]) for k in wiki_passages.column_names]) for p in res_passages]
    res_list = [res for res in res_list if len(res["passage_text"].split()) > min_length][:n_results]
    for r, sc in zip(res_list, D[0]):
        r["score"] = float(sc)
    return support_doc, res_list


def batch_query_qa_dense_index(questions, qa_embedder, tokenizer, wiki_passages, wiki_index, n_results=10):
    q_rep = embed_questions_for_retrieval(questions, tokenizer, qa_embedder)
    D, I = wiki_index.search(q_rep, n_results)
    res_passages_lst = [[wiki_passages[int(i)] for i in i_lst] for i_lst in I]
    support_doc_lst = [
        "<P> " + " <P> ".join([p["passage_text"] for p in res_passages]) for res_passages in res_passages_lst
    ]
    all_res_lists = []
    for (res_passages, dl) in zip(res_passages_lst, D):
        res_list = [dict([(k, p[k]) for k in wiki_passages.column_names]) for p in res_passages]
        for r, sc in zip(res_list, dl):
            r["score"] = float(sc)
        all_res_lists += [res_list[:]]
    return support_doc_lst, all_res_lists


# find nearest neighbors of an answer or declarative text in Wikipedia snippets
def query_qa_dense_index_nn(passage, qa_embedder, tokenizer, wiki_passages, wiki_index, n_results=10, min_length=20):
    a_rep = embed_passages_for_retrieval([passage], tokenizer, qa_embedder)
    D, I = wiki_index.search(a_rep, 2 * n_results)
    res_passages = [wiki_passages[int(i)] for i in I[0]]
    support_doc = "<P> " + " <P> ".join([p["passage_text"] for p in res_passages])
    res_list = [dict([(k, p[k]) for k in wiki_passages.column_names]) for p in res_passages]
    res_list = [res for res in res_list if len(res["passage_text"].split()) > min_length][:n_results]
    for r, sc, i in zip(res_list, D[0], I[0]):
        r["passage_id"] = int(i)
        r["score"] = float(sc)
    return support_doc, res_list


def batch_query_qa_dense_index_nn(passages, qa_embedder, tokenizer, wiki_passages, wiki_index, n_results=10):
    a_reps = embed_passages_for_retrieval(passages, tokenizer, qa_embedder)
    D, I = wiki_index.search(a_reps, n_results)
    res_passages_lst = [[wiki_passages[int(i)] for i in i_lst] for i_lst in I]
    support_doc_lst = [
        "<P> " + " <P> ".join([p["passage_text"] for p in res_passages]) for res_passages in res_passages_lst
    ]
    all_res_lists = []
    for (res_passages, dl, il) in zip(res_passages_lst, D, I):
        res_list = [dict([(k, p[k]) for k in wiki_passages.column_names]) for p in res_passages]
        for r, sc, i in zip(res_list, dl, il):
            r["passage_id"] = int(i)
            r["score"] = float(sc)
        all_res_lists += [res_list[:]]
    return support_doc_lst, all_res_lists