def main()

in mdr/retrieval/train_single.py [0:0]


def main():
    args = train_args()

    if args.fp16:
        apex.amp.register_half_function(torch, 'einsum')

    date_curr = date.today().strftime("%m-%d-%Y")
    model_name = f"{args.prefix}-seed{args.seed}-bsz{args.train_batch_size}-fp16{args.fp16}-lr{args.learning_rate}-decay{args.weight_decay}-warm{args.warmup_ratio}-{args.model_name}"
    args.output_dir = os.path.join(args.output_dir, date_curr, model_name)
    tb_logger = SummaryWriter(os.path.join(args.output_dir.replace("logs","tflogs")))

    if os.path.exists(args.output_dir) and os.listdir(args.output_dir):
        print(
            f"output directory {args.output_dir} already exists and is not empty.")
    os.makedirs(args.output_dir, exist_ok=True)

    logging.basicConfig(format='%(asctime)s - %(levelname)s - %(name)s - %(message)s', datefmt='%m/%d/%Y %H:%M:%S',
                        level=logging.INFO,
                        handlers=[logging.FileHandler(os.path.join(args.output_dir, "log.txt")),
                                  logging.StreamHandler()])
    logger = logging.getLogger(__name__)
    logger.info(args)

    if args.local_rank == -1 or args.no_cuda:
        device = torch.device(
            "cuda" if torch.cuda.is_available() and not args.no_cuda else "cpu")
        n_gpu = torch.cuda.device_count()
    else:
        device = torch.device("cuda", args.local_rank)
        n_gpu = 1
        torch.distributed.init_process_group(backend='nccl')
    logger.info("device %s n_gpu %d distributed training %r",
                device, n_gpu, bool(args.local_rank != -1))

    args.train_batch_size = int(
        args.train_batch_size / args.accumulate_gradients)
    random.seed(args.seed)
    np.random.seed(args.seed)
    torch.manual_seed(args.seed)
    if n_gpu > 0:
        torch.cuda.manual_seed_all(args.seed)
    if not args.do_train and not args.do_predict:
        raise ValueError(
            "At least one of `do_train` or `do_predict` must be True.")

    bert_config = AutoConfig.from_pretrained(args.model_name)
    if args.momentum:
        model = MomentumRetriever(bert_config, args)
    elif "roberta" in args.model_name:
        model = RobertaRetrieverSingle(bert_config, args)
    else:
        model = BertRetrieverSingle(bert_config, args)
    
    tokenizer = AutoTokenizer.from_pretrained(args.model_name)
    collate_fc = partial(sp_collate, pad_id=tokenizer.pad_token_id)

    if args.do_train and args.max_c_len > bert_config.max_position_embeddings:
        raise ValueError(
            "Cannot use sequence length %d because the BERT model "
            "was only trained up to sequence length %d" %
            (args.max_c_len, bert_config.max_position_embeddings))

    if "fever" in args.predict_file:
        eval_dataset = FeverSingleDataset(tokenizer, args.predict_file, args.max_q_len, args.max_c_len)
    else:
        eval_dataset = SPDataset(tokenizer, args.predict_file, args.max_q_len, args.max_c_len)
    eval_dataloader = DataLoader(
        eval_dataset, batch_size=args.predict_batch_size, collate_fn=collate_fc, pin_memory=True, num_workers=args.num_workers)
    logger.info(f"Num of dev batches: {len(eval_dataloader)}")

    if args.init_checkpoint != "":
        model = load_saved(model, args.init_checkpoint)

    model.to(device)
    print(f"number of trainable parameters: {sum(p.numel() for p in model.parameters() if p.requires_grad)}")

    if args.do_train:
        no_decay = ['bias', 'LayerNorm.weight']
        optimizer_parameters = [
            {'params': [p for n, p in model.named_parameters() if not any(
                nd in n for nd in no_decay)], 'weight_decay': args.weight_decay},
            {'params': [p for n, p in model.named_parameters() if any(
                nd in n for nd in no_decay)], 'weight_decay': 0.0}
        ]
        optimizer = Adam(optimizer_parameters, lr=args.learning_rate, eps=args.adam_epsilon)

        if args.fp16:
            model, optimizer = apex.amp.initialize(model, optimizer, opt_level=args.fp16_opt_level)
    else:
        if args.fp16:
            model = apex.amp.initialize(model, opt_level=args.fp16_opt_level)

    if n_gpu > 1:
        model = torch.nn.DataParallel(model)

    if args.do_train:
        global_step = 0 # gradient update step
        batch_step = 0 # forward batch count
        best_mrr = 0
        train_loss_meter = AverageMeter()
        model.train()
        if "fever" in args.predict_file:
            train_dataset = FeverSingleDataset(tokenizer, args.train_file, args.max_q_len, args.max_c_len, train=True)
        else:
            train_dataset = SPDataset(tokenizer, args.train_file, args.max_q_len, args.max_c_len, train=True)
        train_dataloader = DataLoader(train_dataset, batch_size=args.train_batch_size, pin_memory=True, collate_fn=collate_fc, num_workers=args.num_workers, shuffle=True)

        t_total = len(train_dataloader) // args.gradient_accumulation_steps * args.num_train_epochs
        warmup_steps = t_total * args.warmup_ratio
        scheduler = get_linear_schedule_with_warmup(
            optimizer, num_warmup_steps=warmup_steps, num_training_steps=t_total
        )


        logger.info('Start training....')
        for epoch in range(int(args.num_train_epochs)):

            for batch in tqdm(train_dataloader):
                batch_step += 1
                batch = move_to_cuda(batch)
                loss = loss_single(model, batch, args.momentum)

                if args.gradient_accumulation_steps > 1:
                    loss = loss / args.gradient_accumulation_steps

                if args.fp16:
                    with apex.amp.scale_loss(loss, optimizer) as scaled_loss:
                        scaled_loss.backward()
                else:
                    loss.backward()
                train_loss_meter.update(loss.item())

            
                if (batch_step + 1) % args.gradient_accumulation_steps == 0:
                    if args.fp16:
                        torch.nn.utils.clip_grad_norm_(
                            apex.amp.master_params(optimizer), args.max_grad_norm)
                    else:
                        torch.nn.utils.clip_grad_norm_(
                            model.parameters(), args.max_grad_norm)
                    optimizer.step()
                    scheduler.step()
                    model.zero_grad()
                    global_step += 1

                    tb_logger.add_scalar('batch_train_loss',
                                        loss.item(), global_step)
                    tb_logger.add_scalar('smoothed_train_loss',
                                        train_loss_meter.avg, global_step)

                    if args.eval_period != -1 and global_step % args.eval_period == 0:
                        mrr = predict(args, model, eval_dataloader,
                                     device, logger)
                        logger.info("Step %d Train loss %.2f MRR %.2f on epoch=%d" % (global_step, train_loss_meter.avg, mrr*100, epoch))

                        if best_mrr < mrr:
                            logger.info("Saving model with best MRR %.2f -> MRR %.2f on epoch=%d" %
                                        (best_mrr*100, mrr*100, epoch))
                            torch.save(model.state_dict(), os.path.join(
                                args.output_dir, f"checkpoint_best.pt"))
                            model = model.to(device)
                            best_mrr = mrr

            mrr = predict(args, model, eval_dataloader, device, logger)
            logger.info("Step %d Train loss %.2f MRR %.2f on epoch=%d" % (
                global_step, train_loss_meter.avg, mrr*100, epoch))
            tb_logger.add_scalar('dev_mrr', mrr*100, epoch)
            if best_mrr < mrr:
                torch.save(model.state_dict(), os.path.join(
                                args.output_dir, f"checkpoint_last.pt"))
                logger.info("Saving model with best MRR %.2f -> MRR %.2f on epoch=%d" %
                            (best_mrr*100, mrr*100, epoch))
                torch.save(model.state_dict(), os.path.join(
                    args.output_dir, f"checkpoint_best.pt"))
                model = model.to(device)
                best_mrr = mrr

        logger.info("Training finished!")

    elif args.do_predict:
        acc = predict(args, model, eval_dataloader, device, logger)
        logger.info(f"test performance {acc}")