def build_optimizer(
    model,
    optimizer_args,
    math_mode="fp16",
    scaling_args=None,
    fused_adam=False,
    use_horovod=False,
    use_cuda=False,
):
    """Builds the Floating Point optimizer for Transformer. Uses Adam or FusedAdam as
    underlying optimizer

    Args:
        model (:obj:`nn.Module`): The model
        optimizer_args (dict): The arguments for optimizer (eps, weight_decay)
        math_mode (str): One of `fp32` or `fp16`. Default `fp16`
        scaling_args (dict): Arguments for loss scaling (for `float16`). Default `None`
        fused_adam (bool): Use apex's FusedAdam instead
        use_horovod (bool): Use horovod for communication
        use_cuda (bool): Use CUDA tensors for communication

    Returns:
        (:obj:`FP16Optimizer` | :obj:`FP32Optimizer`, :obj:`torch.optim.Optimizer`, :obj:`nn.Module`):
            The FPoptimizer, its underlying Adam or FusedAdam and the model
    """
    if math_mode == "fp16":
        # Half model
        model.half()

        # Build fp16_optimizer
        fp_optimizer = FP16Optimizer(fp16_model=model,
                                     world_size=dist.get_world_size(),
                                     use_cuda=use_cuda,
                                     use_horovod=use_horovod,
                                     average_custom=True,
                                     divide_before=True,
                                     **scaling_args)
        params = [fp_optimizer.fp32_params]

    elif math_mode == "fp32":
        fp_optimizer = FP32Optimizer(
            model=model,
            world_size=dist.get_world_size(),
            use_cuda=use_cuda,
            average_custom=True,
        )
        params = model.parameters()

    else:
        raise NotImplementedError("Unknown math mode {}".format(math_mode))

    if fused_adam:
        optimizer = FusedAdam(params=params, **optimizer_args)
    else:
        optimizer = Adam(params=params, **optimizer_args)
    fp_optimizer.set_optimizer(optimizer)

    return fp_optimizer, optimizer, model
Example #2
0
 def _configure_basic_optimizer(self, model_parameters):
     optimizer_parameters = self.optimizer_params()
     if self.fp16_enabled() and 'max_grad_norm' in optimizer_parameters.keys():
         optimizer_parameters['max_grad_norm'] = 0.0
     if self.optimizer_name() == ADAM_OPTIMIZER:
         optimizer = FusedAdam(model_parameters, **optimizer_parameters)
     elif self.optimizer_name() == LAMB_OPTIMIZER:
         optimizer = FusedLamb(model_parameters, **optimizer_parameters)
     else:
         torch_optimizer = getattr(torch.optim, self.optimizer_name())
         optimizer = torch_optimizer(model_parameters, **optimizer_parameters)
     return optimizer
Example #3
0
 def _configure_basic_optimizer(self, model_parameters):
     optimizer_parameters = self.optimizer_params()
     if 'max_grad_norm' in optimizer_parameters.keys():
         raise ValueError(
             "'max_grad_norm' is not supported as an optimizer parameter, please switch to using the deepspeed parameter 'gradient_clipping' see: https://www.deepspeed.ai/docs/config-json/#gradient-clipping for more details"
         )
     if self.optimizer_name() == ADAM_OPTIMIZER:
         from apex.optimizers.fused_adam import FusedAdam
         optimizer = FusedAdam(model_parameters, **optimizer_parameters)
     elif self.optimizer_name() == LAMB_OPTIMIZER:
         optimizer = FusedLamb(model_parameters, **optimizer_parameters)
     else:
         torch_optimizer = getattr(torch.optim, self.optimizer_name())
         optimizer = torch_optimizer(model_parameters, **optimizer_parameters)
     return optimizer
Example #4
0
 def __init__(self, args, params):
     super().__init__(args, params)
     self._optimizer = FusedAdam(params, **self.optimizer_config)
def main():
    parser = argparse.ArgumentParser()

    # Required parameters
    parser.add_argument(
        "--data_dir",
        default=None,
        type=str,
        required=True,
        help=
        "The input data dir. Should contain the .tsv files (or other data files) for the task."
    )
    parser.add_argument("--src_file",
                        default=None,
                        type=str,
                        help="The input data file name.")
    parser.add_argument("--tgt_file",
                        default=None,
                        type=str,
                        help="The output data file name.")
    parser.add_argument(
        "--bert_model",
        default=None,
        type=str,
        required=True,
        help="Bert pre-trained model selected in the list: bert-base-uncased, "
        "bert-large-uncased, bert-base-cased, bert-base-multilingual, bert-base-chinese."
    )
    parser.add_argument("--config_path",
                        default=None,
                        type=str,
                        help="Bert config file path.")
    parser.add_argument(
        "--output_dir",
        default=None,
        type=str,
        required=True,
        help=
        "The output directory where the model predictions and checkpoints will be written."
    )
    parser.add_argument(
        "--log_dir",
        default='',
        type=str,
        required=True,
        help="The output directory where the log will be written.")
    parser.add_argument("--model_recover_path",
                        default=None,
                        type=str,
                        required=True,
                        help="The file of fine-tuned pretraining model.")
    parser.add_argument("--optim_recover_path",
                        default=None,
                        type=str,
                        help="The file of pretraining optimizer.")

    # Other parameters
    parser.add_argument(
        "--max_seq_length",
        default=128,
        type=int,
        help=
        "The maximum total input sequence length after WordPiece tokenization. \n"
        "Sequences longer than this will be truncated, and sequences shorter \n"
        "than this will be padded.")
    parser.add_argument("--do_train",
                        action='store_true',
                        help="Whether to run training.")
    parser.add_argument("--do_eval",
                        action='store_true',
                        help="Whether to run eval on the dev set.")
    parser.add_argument(
        "--do_lower_case",
        action='store_true',
        help="Set this flag if you are using an uncased model.")
    parser.add_argument("--train_batch_size",
                        default=32,
                        type=int,
                        help="Total batch size for training.")
    parser.add_argument("--eval_batch_size",
                        default=64,
                        type=int,
                        help="Total batch size for eval.")
    parser.add_argument("--learning_rate",
                        default=5e-5,
                        type=float,
                        help="The initial learning rate for Adam.")
    parser.add_argument("--label_smoothing",
                        default=0,
                        type=float,
                        help="The initial learning rate for Adam.")
    parser.add_argument("--weight_decay",
                        default=0.01,
                        type=float,
                        help="The weight decay rate for Adam.")
    parser.add_argument("--finetune_decay",
                        action='store_true',
                        help="Weight decay to the original weights.")
    parser.add_argument("--num_train_epochs",
                        default=3.0,
                        type=float,
                        help="Total number of training epochs to perform.")
    parser.add_argument(
        "--warmup_proportion",
        default=0.1,
        type=float,
        help=
        "Proportion of training to perform linear learning rate warmup for. "
        "E.g., 0.1 = 10%% of training.")
    parser.add_argument("--hidden_dropout_prob",
                        default=0.1,
                        type=float,
                        help="Dropout rate for hidden states.")
    parser.add_argument("--attention_probs_dropout_prob",
                        default=0.1,
                        type=float,
                        help="Dropout rate for attention probabilities.")
    parser.add_argument("--no_cuda",
                        action='store_true',
                        help="Whether not to use CUDA when available")
    parser.add_argument("--local_rank",
                        type=int,
                        default=-1,
                        help="local_rank for distributed training on gpus")
    parser.add_argument('--seed',
                        type=int,
                        default=42,
                        help="random seed for initialization")
    parser.add_argument(
        '--gradient_accumulation_steps',
        type=int,
        default=1,
        help=
        "Number of updates steps to accumulate before performing a backward/update pass."
    )
    parser.add_argument(
        '--fp16',
        action='store_true',
        help="Whether to use 16-bit float precision instead of 32-bit")
    parser.add_argument(
        '--fp32_embedding',
        action='store_true',
        help=
        "Whether to use 32-bit float precision instead of 16-bit for embeddings"
    )
    parser.add_argument(
        '--loss_scale',
        type=float,
        default=0,
        help=
        "Loss scaling to improve fp16 numeric stability. Only used when fp16 set to True.\n"
        "0 (default value): dynamic loss scaling.\n"
        "Positive power of 2: static loss scaling value.\n")
    parser.add_argument('--amp',
                        action='store_true',
                        help="Whether to use amp for fp16")
    parser.add_argument(
        '--from_scratch',
        action='store_true',
        help=
        "Initialize parameters with random values (i.e., training from scratch)."
    )
    parser.add_argument('--new_segment_ids',
                        action='store_true',
                        help="Use new segment ids for bi-uni-directional LM.")
    parser.add_argument('--new_pos_ids',
                        action='store_true',
                        help="Use new position ids for LMs.")
    parser.add_argument('--tokenized_input',
                        action='store_true',
                        help="Whether the input is tokenized.")
    parser.add_argument('--max_len_a',
                        type=int,
                        default=0,
                        help="Truncate_config: maximum length of segment A.")
    parser.add_argument('--max_len_b',
                        type=int,
                        default=0,
                        help="Truncate_config: maximum length of segment B.")
    parser.add_argument(
        '--trunc_seg',
        default='',
        help="Truncate_config: first truncate segment A/B (option: a, b).")
    parser.add_argument(
        '--always_truncate_tail',
        action='store_true',
        help="Truncate_config: Whether we should always truncate tail.")
    parser.add_argument(
        "--mask_prob",
        default=0.15,
        type=float,
        help=
        "Number of prediction is sometimes less than max_pred when sequence is short."
    )
    parser.add_argument(
        "--mask_prob_eos",
        default=0,
        type=float,
        help=
        "Number of prediction is sometimes less than max_pred when sequence is short."
    )
    parser.add_argument('--max_pred',
                        type=int,
                        default=20,
                        help="Max tokens of prediction.")
    parser.add_argument("--num_workers",
                        default=0,
                        type=int,
                        help="Number of workers for the data loader.")

    parser.add_argument('--mask_source_words',
                        action='store_true',
                        help="Whether to mask source words for training")
    parser.add_argument('--skipgram_prb',
                        type=float,
                        default=0.0,
                        help='prob of ngram mask')
    parser.add_argument('--skipgram_size',
                        type=int,
                        default=1,
                        help='the max size of ngram mask')
    parser.add_argument('--mask_whole_word',
                        action='store_true',
                        help="Whether masking a whole word.")
    parser.add_argument('--do_l2r_training',
                        action='store_true',
                        help="Whether to do left to right training")
    parser.add_argument(
        '--has_sentence_oracle',
        action='store_true',
        help="Whether to have sentence level oracle for training. "
        "Only useful for summary generation")
    parser.add_argument('--max_position_embeddings',
                        type=int,
                        default=None,
                        help="max position embeddings")
    parser.add_argument('--relax_projection',
                        action='store_true',
                        help="Use different projection layers for tasks.")
    parser.add_argument('--ffn_type',
                        default=0,
                        type=int,
                        help="0: default mlp; 1: W((Wx+b) elem_prod x);")
    parser.add_argument('--num_qkv',
                        default=0,
                        type=int,
                        help="Number of different <Q,K,V>.")
    parser.add_argument('--seg_emb',
                        action='store_true',
                        help="Using segment embedding for self-attention.")
    parser.add_argument(
        '--s2s_special_token',
        action='store_true',
        help="New special tokens ([S2S_SEP]/[S2S_CLS]) of S2S.")
    parser.add_argument('--s2s_add_segment',
                        action='store_true',
                        help="Additional segmental for the encoder of S2S.")
    parser.add_argument(
        '--s2s_share_segment',
        action='store_true',
        help=
        "Sharing segment embeddings for the encoder of S2S (used with --s2s_add_segment)."
    )
    parser.add_argument('--pos_shift',
                        action='store_true',
                        help="Using position shift for fine-tuning.")

    args = parser.parse_args()

    assert Path(
        args.model_recover_path).exists(), "--model_recover_path doesn't exist"

    args.output_dir = args.output_dir.replace('[PT_OUTPUT_DIR]',
                                              os.getenv('PT_OUTPUT_DIR', ''))
    args.log_dir = args.log_dir.replace('[PT_OUTPUT_DIR]',
                                        os.getenv('PT_OUTPUT_DIR', ''))

    os.makedirs(args.output_dir, exist_ok=True)
    os.makedirs(args.log_dir, exist_ok=True)
    json.dump(args.__dict__,
              open(os.path.join(args.output_dir, 'opt.json'), 'w'),
              sort_keys=True,
              indent=2)

    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:
        torch.cuda.set_device(args.local_rank)
        device = torch.device("cuda", args.local_rank)
        n_gpu = 1
        # Initializes the distributed backend which will take care of sychronizing nodes/GPUs
        dist.init_process_group(backend='nccl')
    logger.info(
        "device: {} n_gpu: {}, distributed training: {}, 16-bits training: {}".
        format(device, n_gpu, bool(args.local_rank != -1), args.fp16))

    if args.gradient_accumulation_steps < 1:
        raise ValueError(
            "Invalid gradient_accumulation_steps parameter: {}, should be >= 1"
            .format(args.gradient_accumulation_steps))

    args.train_batch_size = int(args.train_batch_size /
                                args.gradient_accumulation_steps)

    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_eval:
        raise ValueError(
            "At least one of `do_train` or `do_eval` must be True.")

    if args.local_rank not in (-1, 0):
        # Make sure only the first process in distributed training will download model & vocab
        dist.barrier()
    tokenizer = BertTokenizer.from_pretrained(args.bert_model,
                                              do_lower_case=args.do_lower_case)
    if args.max_position_embeddings:
        tokenizer.max_len = args.max_position_embeddings
    data_tokenizer = WhitespaceTokenizer(
    ) if args.tokenized_input else tokenizer
    if args.local_rank == 0:
        dist.barrier()

    if args.do_train:
        print("Loading Train Dataset", args.data_dir)
        bi_uni_pipeline = [
            seq2seq_loader.Preprocess4Seq2seq(
                args.max_pred,
                args.mask_prob,
                list(tokenizer.vocab.keys()),
                tokenizer.convert_tokens_to_ids,
                args.max_seq_length,
                new_segment_ids=args.new_segment_ids,
                truncate_config={
                    'max_len_a': args.max_len_a,
                    'max_len_b': args.max_len_b,
                    'trunc_seg': args.trunc_seg,
                    'always_truncate_tail': args.always_truncate_tail
                },
                mask_source_words=args.mask_source_words,
                skipgram_prb=args.skipgram_prb,
                skipgram_size=args.skipgram_size,
                mask_whole_word=args.mask_whole_word,
                mode="s2s",
                has_oracle=args.has_sentence_oracle,
                num_qkv=args.num_qkv,
                s2s_special_token=args.s2s_special_token,
                s2s_add_segment=args.s2s_add_segment,
                s2s_share_segment=args.s2s_share_segment,
                pos_shift=args.pos_shift)
        ]
        file_oracle = None
        if args.has_sentence_oracle:
            file_oracle = os.path.join(args.data_dir, 'train.oracle')
        fn_src = os.path.join(args.data_dir,
                              args.src_file if args.src_file else 'train.src')
        fn_tgt = os.path.join(args.data_dir,
                              args.tgt_file if args.tgt_file else 'train.tgt')
        train_dataset = seq2seq_loader.Seq2SeqDataset(
            fn_src,
            fn_tgt,
            args.train_batch_size,
            data_tokenizer,
            args.max_seq_length,
            file_oracle=file_oracle,
            bi_uni_pipeline=bi_uni_pipeline)
        if args.local_rank == -1:
            train_sampler = RandomSampler(train_dataset, replacement=False)
            _batch_size = args.train_batch_size
        else:
            train_sampler = DistributedSampler(train_dataset)
            _batch_size = args.train_batch_size // dist.get_world_size()
        train_dataloader = torch.utils.data.DataLoader(
            train_dataset,
            batch_size=_batch_size,
            sampler=train_sampler,
            num_workers=args.num_workers,
            collate_fn=seq2seq_loader.batch_list_to_batch_tensors,
            pin_memory=False)

    # note: args.train_batch_size has been changed to (/= args.gradient_accumulation_steps)
    # t_total = int(math.ceil(len(train_dataset.ex_list) / args.train_batch_size)
    t_total = int(
        len(train_dataloader) * args.num_train_epochs /
        args.gradient_accumulation_steps)

    amp_handle = None
    if args.fp16 and args.amp:
        from apex import amp
        amp_handle = amp.init(enable_caching=True)
        logger.info("enable fp16 with amp")

    # Prepare model
    recover_step = _get_max_epoch_model(args.output_dir)
    cls_num_labels = 2
    type_vocab_size = 6 + \
        (1 if args.s2s_add_segment else 0) if args.new_segment_ids else 2
    num_sentlvl_labels = 2 if args.has_sentence_oracle else 0
    relax_projection = 4 if args.relax_projection else 0
    if args.local_rank not in (-1, 0):
        # Make sure only the first process in distributed training will download model & vocab
        dist.barrier()
    if (recover_step is None) and (args.model_recover_path is None):
        # if _state_dict == {}, the parameters are randomly initialized
        # if _state_dict == None, the parameters are initialized with bert-init
        _state_dict = {} if args.from_scratch else None
        model = BertForPreTrainingLossMask.from_pretrained(
            args.bert_model,
            state_dict=_state_dict,
            num_labels=cls_num_labels,
            num_rel=0,
            type_vocab_size=type_vocab_size,
            config_path=args.config_path,
            task_idx=3,
            num_sentlvl_labels=num_sentlvl_labels,
            max_position_embeddings=args.max_position_embeddings,
            label_smoothing=args.label_smoothing,
            fp32_embedding=args.fp32_embedding,
            relax_projection=relax_projection,
            new_pos_ids=args.new_pos_ids,
            ffn_type=args.ffn_type,
            hidden_dropout_prob=args.hidden_dropout_prob,
            attention_probs_dropout_prob=args.attention_probs_dropout_prob,
            num_qkv=args.num_qkv,
            seg_emb=args.seg_emb)
        global_step = 0
    else:
        if recover_step:
            logger.info("***** Recover model: %d *****", recover_step)
            model_recover = torch.load(os.path.join(
                args.output_dir, "model.{0}.bin".format(recover_step)),
                                       map_location='cpu')
            # recover_step == number of epochs
            global_step = math.floor(recover_step * t_total /
                                     args.num_train_epochs)
        elif args.model_recover_path:
            logger.info("***** Recover model: %s *****",
                        args.model_recover_path)
            model_recover = torch.load(args.model_recover_path,
                                       map_location='cpu')
            global_step = 0
        model = BertForPreTrainingLossMask.from_pretrained(
            args.bert_model,
            state_dict=model_recover,
            num_labels=cls_num_labels,
            num_rel=0,
            type_vocab_size=type_vocab_size,
            config_path=args.config_path,
            task_idx=3,
            num_sentlvl_labels=num_sentlvl_labels,
            max_position_embeddings=args.max_position_embeddings,
            label_smoothing=args.label_smoothing,
            fp32_embedding=args.fp32_embedding,
            relax_projection=relax_projection,
            new_pos_ids=args.new_pos_ids,
            ffn_type=args.ffn_type,
            hidden_dropout_prob=args.hidden_dropout_prob,
            attention_probs_dropout_prob=args.attention_probs_dropout_prob,
            num_qkv=args.num_qkv,
            seg_emb=args.seg_emb)
    if args.local_rank == 0:
        dist.barrier()

    if args.fp16:
        model.half()
        if args.fp32_embedding:
            model.bert.embeddings.word_embeddings.float()
            model.bert.embeddings.position_embeddings.float()
            model.bert.embeddings.token_type_embeddings.float()
    model.to(device)
    if args.local_rank != -1:
        try:
            from torch.nn.parallel.distributed import DistributedDataParallel as DDP
        except ImportError:
            raise ImportError("DistributedDataParallel")
        model = DDP(model,
                    device_ids=[args.local_rank],
                    output_device=args.local_rank,
                    find_unused_parameters=True)
    elif n_gpu > 1:
        #model = torch.nn.DataParallel(model)
        model = DataParallelImbalance(model)

    # Prepare optimizer
    param_optimizer = list(model.named_parameters())
    no_decay = ['bias', 'LayerNorm.bias', 'LayerNorm.weight']
    optimizer_grouped_parameters = [{
        'params':
        [p for n, p in param_optimizer if not any(nd in n for nd in no_decay)],
        'weight_decay':
        0.01
    }, {
        'params':
        [p for n, p in param_optimizer if any(nd in n for nd in no_decay)],
        'weight_decay':
        0.0
    }]
    if args.fp16:
        try:
            #from apex.optimizers.fp16_optimizer import FP16_Optimizer
            from pytorch_pretrained_bert.optimization_fp16 import FP16_Optimizer_State
            from apex.optimizers.fused_adam import FusedAdam
        except ImportError:
            raise ImportError(
                "Please install apex from https://www.github.com/nvidia/apex to use distributed and fp16 training."
            )

        optimizer = FusedAdam(optimizer_grouped_parameters,
                              lr=args.learning_rate,
                              bias_correction=False)
        if args.loss_scale == 0:
            optimizer = FP16_Optimizer_State(optimizer,
                                             dynamic_loss_scale=True)
        else:
            optimizer = FP16_Optimizer_State(optimizer,
                                             static_loss_scale=args.loss_scale)
    else:
        optimizer = BertAdam(optimizer_grouped_parameters,
                             lr=args.learning_rate,
                             warmup=args.warmup_proportion,
                             t_total=t_total)

    if recover_step:
        logger.info("***** Recover optimizer: %d *****", recover_step)
        optim_recover = torch.load(os.path.join(
            args.output_dir, "optim.{0}.bin".format(recover_step)),
                                   map_location='cpu')
        if hasattr(optim_recover, 'state_dict'):
            optim_recover = optim_recover.state_dict()
        optimizer.load_state_dict(optim_recover)
        if args.loss_scale == 0:
            logger.info("***** Recover optimizer: dynamic_loss_scale *****")
            optimizer.dynamic_loss_scale = True

    logger.info("***** CUDA.empty_cache() *****")
    torch.cuda.empty_cache()

    if args.do_train:
        logger.info("***** Running training *****")
        logger.info("  Batch size = %d", args.train_batch_size)
        logger.info("  Num steps = %d", t_total)

        model.train()
        if recover_step:
            start_epoch = recover_step + 1
        else:
            start_epoch = 1
        for i_epoch in trange(start_epoch,
                              int(args.num_train_epochs) + 1,
                              desc="Epoch",
                              disable=args.local_rank not in (-1, 0)):
            if args.local_rank != -1:
                train_sampler.set_epoch(i_epoch)
            iter_bar = tqdm(train_dataloader,
                            desc='Iter (loss=X.XXX)',
                            disable=args.local_rank not in (-1, 0))
            for step, batch in enumerate(iter_bar):
                batch = [
                    t.to(device) if t is not None else None for t in batch
                ]
                if args.has_sentence_oracle:
                    input_ids, segment_ids, input_mask, mask_qkv, lm_label_ids, masked_pos, masked_weights, is_next, task_idx, oracle_pos, oracle_weights, oracle_labels = batch
                else:
                    input_ids, segment_ids, input_mask, mask_qkv, lm_label_ids, masked_pos, masked_weights, is_next, task_idx = batch
                    oracle_pos, oracle_weights, oracle_labels = None, None, None
                loss_tuple = model(input_ids,
                                   segment_ids,
                                   input_mask,
                                   lm_label_ids,
                                   is_next,
                                   masked_pos=masked_pos,
                                   masked_weights=masked_weights,
                                   task_idx=task_idx,
                                   masked_pos_2=oracle_pos,
                                   masked_weights_2=oracle_weights,
                                   masked_labels_2=oracle_labels,
                                   mask_qkv=mask_qkv)
                masked_lm_loss, next_sentence_loss = loss_tuple
                if n_gpu > 1:  # mean() to average on multi-gpu.
                    # loss = loss.mean()
                    masked_lm_loss = masked_lm_loss.mean()
                    next_sentence_loss = next_sentence_loss.mean()
                loss = masked_lm_loss + next_sentence_loss

                # logging for each step (i.e., before normalization by args.gradient_accumulation_steps)
                iter_bar.set_description('Iter (loss=%5.3f)' % loss.item())

                # ensure that accumlated gradients are normalized
                if args.gradient_accumulation_steps > 1:
                    loss = loss / args.gradient_accumulation_steps

                if args.fp16:
                    optimizer.backward(loss)
                    if amp_handle:
                        amp_handle._clear_cache()
                else:
                    loss.backward()
                if (step + 1) % args.gradient_accumulation_steps == 0:
                    lr_this_step = args.learning_rate * \
                        warmup_linear(global_step/t_total,
                                      args.warmup_proportion)
                    if args.fp16:
                        # modify learning rate with special warm up BERT uses
                        for param_group in optimizer.param_groups:
                            param_group['lr'] = lr_this_step
                    optimizer.step()
                    optimizer.zero_grad()
                    global_step += 1

            # Save a trained model
            if (args.local_rank == -1 or torch.distributed.get_rank() == 0):
                logger.info(
                    "** ** * Saving fine-tuned model and optimizer ** ** * ")
                model_to_save = model.module if hasattr(
                    model, 'module') else model  # Only save the model it-self
                output_model_file = os.path.join(
                    args.output_dir, "model.{0}.bin".format(i_epoch))
                torch.save(model_to_save.state_dict(), output_model_file)
                output_optim_file = os.path.join(
                    args.output_dir, "optim.{0}.bin".format(i_epoch))
                torch.save(optimizer.state_dict(), output_optim_file)

                logger.info("***** CUDA.empty_cache() *****")
                torch.cuda.empty_cache()