コード例 #1
0
    def test_horovod_allgather_type_error(self):
        """Test that the allgather returns an error if the types being gathered
        differ among the processes"""
        hvd.init()
        rank = hvd.rank()
        size = hvd.size()

        # This test does not apply if there is only one worker.
        if size == 1:
            self.skipTest("Only one worker available")

        ctx = self._current_context()

        tensor_size = [17] * 3
        if rank % 2 == 0:
            tensor = mx.ndarray.ones(shape=tensor_size, dtype="int32", ctx=ctx)
        else:
            tensor = mx.ndarray.ones(shape=tensor_size,
                                     dtype="float32",
                                     ctx=ctx)

        try:
            hvd.allgather(tensor)
            assert False, 'hvd.allgather did not throw error'
        except (MXNetError, RuntimeError):
            pass
コード例 #2
0
    def test_horovod_allgather_variable_size(self):
        """Test that the allgather correctly gathers 1D, 2D, 3D tensors,
        even if those tensors have different sizes along the first dim."""
        hvd.init()
        rank = hvd.rank()
        size = hvd.size()

        dtypes = ['int32', 'int64', 'float32', 'float64']
        dims = [1, 2, 3]
        ctx = self._current_context()
        for dtype, dim in itertools.product(dtypes, dims):
            # Support tests up to MPI Size of 35
            if size > 35:
                break

            tensor_sizes = [17, 32, 81, 12, 15, 23, 22] * 5
            tensor_sizes = tensor_sizes[:size]

            tensor = mx.ndarray.ones(shape=[tensor_sizes[rank]] + [17] *
                                     (dim - 1),
                                     dtype=dtype,
                                     ctx=ctx) * rank

            gathered = hvd.allgather(tensor)

            expected_size = sum(tensor_sizes)
            assert list(gathered.shape) == [expected_size] + [17] * (dim - 1)

            for i in range(size):
                rank_size = [tensor_sizes[i]] + [17] * (dim - 1)
                rank_tensor = gathered[sum(tensor_sizes[:i]
                                           ):sum(tensor_sizes[:i + 1])]
                assert list(rank_tensor.shape) == rank_size
                assert rank_tensor.min() == i
                assert rank_tensor.max() == i
コード例 #3
0
 def allgather(self, array):
     if self.ALL_GATHER_WITH_MPI4PY:
         array = array.copyto(mx.cpu())
         array = comm.allgather(array)  # Do All gather
         array = mx.nd.concat(*array, dim=0)  # Concatenate all ranks
     else:
         array = hvd.allgather(array)
     return array
コード例 #4
0
    def test_horovod_allgather_error(self):
        """Test that the allgather returns an error if any dimension besides
        the first is different among the tensors being gathered."""
        hvd.init()
        rank = hvd.rank()
        size = hvd.size()

        # This test does not apply if there is only one worker.
        if size == 1:
            self.skipTest("Only one worker available")

        ctx = self._current_context()

        tensor_size = [17] * 3
        tensor_size[1] = 10 * (rank + 1)
        tensor = mx.ndarray.ones(shape=tensor_size, ctx=ctx)

        try:
            hvd.allgather(tensor)
            assert False, 'hvd.allgather did not throw error'
        except (MXNetError, RuntimeError):
            pass
コード例 #5
0
ファイル: test_mxnet.py プロジェクト: tallamjr/horovod
    def test_horovod_allgather(self):
        """Test that the allgather correctly gathers 1D, 2D, 3D tensors."""
        hvd.init()
        rank = hvd.rank()
        size = hvd.size()

        dtypes = ['int32',   'int64',
                  'float32', 'float64']
        dims = [1, 2, 3]
        ctx = self._current_context()
        for dtype, dim in itertools.product(dtypes, dims):
            tensor = mx.ndarray.ones(shape=[17] * dim, dtype=dtype, ctx=ctx) * rank
            gathered = hvd.allgather(tensor)

            assert list(gathered.shape) == [17 * size] + [17] * (dim - 1)

            for i in range(size):
                rank_tensor = gathered[i * 17:(i + 1) * 17]
                assert list(rank_tensor.shape) == [17] * dim, \
                    'hvd.allgather produces incorrect gathered shape'
                assert rank_tensor.min() == i, 'hvd.allgather produces incorrect gathered tensor'
                assert rank_tensor.max() == i, 'hvd.allgather produces incorrect gathered tensor'
コード例 #6
0
def train(args):
    _, num_parts, rank, local_rank, _, ctx_l = init_comm(
        args.comm_backend, args.gpus)
    if args.comm_backend == 'horovod':
        logging_config(
            args.save_dir,
            name=f'train_transformer_rank{rank}_local{local_rank}_{num_parts}',
            console=(rank == 0))
        logging.info(args)
    else:
        logging_config(args.save_dir, name='train_transformer', console=True)
        logging.info(args)
    use_amp = args.fp16
    if use_amp:
        from mxnet import amp
    src_tokenizer = create_tokenizer(args.src_tokenizer,
                                     args.src_subword_model_path,
                                     args.src_vocab_path)
    tgt_tokenizer = create_tokenizer(args.tgt_tokenizer,
                                     args.tgt_subword_model_path,
                                     args.tgt_vocab_path)
    base_tgt_tokenizer = MosesTokenizer(args.tgt_lang)
    src_vocab = src_tokenizer.vocab
    tgt_vocab = tgt_tokenizer.vocab
    train_src_data, train_tgt_data = load_dataset_with_cache(
        args.train_src_corpus,
        args.train_tgt_corpus,
        src_tokenizer,
        tgt_tokenizer,
        args.overwrite_cache,
        local_rank,
        max_src_length=args.max_src_length,
        max_tgt_length=args.max_tgt_length,
        pretokenized=not args.tokenize)
    dev_src_data, dev_tgt_data = load_dataset_with_cache(
        args.dev_src_corpus,
        args.dev_tgt_corpus,
        src_tokenizer,
        tgt_tokenizer,
        args.overwrite_cache,
        local_rank,
        pretokenized=not args.tokenize)
    tgt_detok_sentences = []
    tgt_raw_sentences = []
    with open(args.dev_tgt_corpus, 'r') as in_f:
        for line in in_f:
            tgt_detok_sentences.append(
                base_tgt_tokenizer.decode(
                    tgt_tokenizer.decode(line.split()).split()))
    with open(args.dev_tgt_raw_corpus, 'r') as in_f:
        for line in in_f:
            tgt_raw_sentences.append(line.strip())
    data_train = gluon.data.SimpleDataset([
        (src_tokens, tgt_tokens, len(src_tokens), len(tgt_tokens), i)
        for i, (src_tokens,
                tgt_tokens) in enumerate(zip(train_src_data, train_tgt_data))
    ])
    val_samples = [
        (src_tokens, tgt_tokens, len(src_tokens), len(tgt_tokens), i)
        for i, (src_tokens,
                tgt_tokens) in enumerate(zip(dev_src_data, dev_tgt_data))
    ]
    if args.comm_backend == 'horovod':
        slice_begin = rank * (len(val_samples) // num_parts)
        slice_end = min((rank + 1) * (len(val_samples) // num_parts),
                        len(val_samples))
        data_val = gluon.data.SimpleDataset(val_samples[slice_begin:slice_end])
    else:
        data_val = gluon.data.SimpleDataset(val_samples)
    # Construct the model + loss function
    if args.cfg.endswith('.yml'):
        cfg = TransformerModel.get_cfg().clone_merge(args.cfg)
    else:
        cfg = TransformerModel.get_cfg(args.cfg)
    cfg.defrost()
    cfg.MODEL.src_vocab_size = len(src_vocab)
    cfg.MODEL.tgt_vocab_size = len(tgt_vocab)
    cfg.MODEL.layout = 'TN'
    cfg.freeze()
    model = TransformerModel.from_cfg(cfg)
    model.initialize(mx.init.Xavier(magnitude=args.magnitude), ctx=ctx_l)
    model.hybridize()
    for v in model.collect_params().values():
        if v.grad_req != 'null':
            v.grad_req = 'add'
    # Do not apply weight decay to all the LayerNorm and bias
    for _, v in model.collect_params('.*beta|.*gamma|.*bias').items():
        v.wd_mult = 0.0
    param_dict = deduplicate_param_dict(model.collect_params())

    inference_model = TransformerInference(model=model)
    inference_model.hybridize()
    if local_rank == 0:
        logging.info(model)
    with open(os.path.join(args.save_dir, 'config.yml'), 'w') as cfg_f:
        cfg_f.write(cfg.dump())
    label_smooth_loss = LabelSmoothCrossEntropyLoss(
        num_labels=len(tgt_vocab),
        alpha=args.label_smooth_alpha,
        from_logits=False)
    label_smooth_loss.hybridize()

    # Construct the beam search sampler
    scorer = BeamSearchScorer(alpha=args.lp_alpha,
                              K=args.lp_k,
                              from_logits=False)
    beam_search_sampler = BeamSearchSampler(beam_size=args.beam_size,
                                            decoder=inference_model,
                                            vocab_size=len(tgt_vocab),
                                            eos_id=tgt_vocab.eos_id,
                                            scorer=scorer,
                                            stochastic=False,
                                            max_length_a=args.max_length_a,
                                            max_length_b=args.max_length_b)

    logging.info(beam_search_sampler)
    if args.comm_backend == 'horovod':
        hvd.broadcast_parameters(param_dict, root_rank=0)

    # Construct the trainer
    if args.lr is None:
        base_lr = 2.0 / math.sqrt(args.num_units) / math.sqrt(
            args.warmup_steps)
    else:
        base_lr = args.lr
    lr_scheduler = InverseSquareRootScheduler(
        warmup_steps=args.warmup_steps,
        base_lr=base_lr,
        warmup_init_lr=args.warmup_init_lr)
    optimizer_params = {
        'learning_rate': args.lr,
        'beta1': 0.9,
        'beta2': 0.997,
        'epsilon': 1e-9,
        'lr_scheduler': lr_scheduler,
        'wd': args.wd
    }
    user_provided_ptimizer_params = json.loads(args.optimizer_params)
    optimizer_params.update(user_provided_ptimizer_params)

    if args.fp16:
        optimizer_params.update({'multi_precision': True})
    if args.comm_backend == 'horovod':
        trainer = hvd.DistributedTrainer(param_dict, args.optimizer,
                                         optimizer_params)
    else:
        trainer = gluon.Trainer(param_dict,
                                args.optimizer,
                                optimizer_params,
                                update_on_kvstore=False)
    # Load Data
    if args.sampler == 'BoundedBudgetSampler':
        train_batch_sampler = BoundedBudgetSampler(
            lengths=[(ele[2], ele[3]) for ele in data_train],
            max_num_tokens=args.max_num_tokens,
            max_num_sentences=args.max_num_sentences,
            shuffle=True,
            seed=args.seed)
    elif args.sampler == 'FixedBucketSampler':
        if args.comm_backend == 'horovod':
            raise NotImplementedError(
                'FixedBucketSampler does not support horovod at present')

        if args.bucket_scheme == 'constant':
            bucket_scheme = ConstWidthBucket()
        elif args.bucket_scheme == 'linear':
            bucket_scheme = LinearWidthBucket()
        elif args.bucket_scheme == 'exp':
            bucket_scheme = ExpWidthBucket(bucket_len_step=1.2)
        else:
            raise NotImplementedError
        # TODO(sxjscience) Support auto-bucket-size tuning
        train_batch_sampler = FixedBucketSampler(lengths=[
            (ele[2], ele[3]) for ele in data_train
        ],
                                                 batch_size=args.batch_size,
                                                 num_buckets=args.num_buckets,
                                                 ratio=args.bucket_ratio,
                                                 shuffle=True,
                                                 use_average_length=True,
                                                 bucket_scheme=bucket_scheme,
                                                 seed=args.seed)
    else:
        raise NotImplementedError

    num_updates_per_epoch = int(
        math.ceil(
            len(train_batch_sampler) /
            (num_parts * len(ctx_l) * args.num_accumulated)))
    # Convert the batch sampler to multiple shards
    if num_parts > 1:
        train_batch_sampler = ShardedIterator(train_batch_sampler,
                                              num_parts=num_parts,
                                              part_index=rank,
                                              even_size=True,
                                              seed=args.seed + 1000 * rank)

    logging.info(train_batch_sampler)

    batchify_fn = bf.Tuple(bf.Pad(), bf.Pad(), bf.Stack(), bf.Stack(),
                           bf.Stack())
    train_data_loader = gluon.data.DataLoader(
        data_train,
        batch_sampler=train_batch_sampler,
        batchify_fn=batchify_fn,
        num_workers=0)
    val_data_loader = gluon.data.DataLoader(data_val,
                                            batch_size=args.val_batch_size,
                                            batchify_fn=batchify_fn,
                                            num_workers=0,
                                            shuffle=False)
    params = [p for p in param_dict.values() if p.grad_req != 'null']
    model_averager = AverageSGDTracker(param_dict)
    log_start_time = time.time()
    num_params, num_fixed_params = None, None

    # TODO(sxjscience) Add a log metric class
    log_avg_loss_l = [mx.np.array(0.0, ctx=ctx) for ctx in ctx_l]
    # Maintain the denominator of the loss.
    log_avg_loss_denom_l = [mx.np.array(0.0, ctx=ctx) for ctx in ctx_l]
    log_wc_l = [mx.np.array(0, dtype=np.int64, ctx=ctx) for ctx in ctx_l]
    log_tgt_wc_l = [mx.np.array(0, dtype=np.int64, ctx=ctx) for ctx in ctx_l]
    log_avg_grad_norm = 0
    log_iter_num = 0

    if local_rank == 0:
        writer = SummaryWriter(
            logdir=os.path.join(args.save_dir, 'tensorboard'))
    if use_amp:
        amp.init_trainer(trainer)
    train_multi_data_loader = grouper(repeat(train_data_loader), len(ctx_l))
    # when args.epochs < 0, the model will keep training
    if args.epochs < 0:
        if args.max_update > 0:
            total_train_iters = args.max_update
            if args.num_averages > 0:
                assert args.num_averages <= total_train_iters // args.save_iterval_update
                avg_start_iter = (
                    total_train_iters // args.save_iterval_update -
                    args.num_averages) * args.save_iterval_update
            else:
                avg_start_iter = -1
        else:
            total_train_iters = np.inf
            avg_start_iter = -1
    else:
        total_train_iters = args.epochs * num_updates_per_epoch
        if args.num_averages > 0:
            assert args.num_averages <= args.epochs
            avg_start_iter = (args.epochs -
                              args.num_average) * num_updates_per_epoch
        else:
            avg_start_iter = -1

    # Here, we are manually setting up the scale to 1.0 because
    # in horovod, the scale can be the number of workers:
    # See the code here: https://github.com/horovod/horovod/blob/125115583b7029196e2ec530decd4209459d5479/horovod/mxnet/__init__.py#L141
    # Since we will need to use the dynamic scaling in amp, we will manually call amp.unscale().
    # A scale that is larger than 1.0 can be problematic in this case.
    trainer._scale = 1.0
    if args.max_num_tokens > 0:
        const_scale = args.max_num_tokens
    else:
        const_scale = 100

    train_start_time = time.time()

    for train_iter in range(total_train_iters):
        model.zero_grad()
        loss_denom_l = [mx.np.array(0.0, ctx=ctx) for ctx in ctx_l]
        for i in range(args.num_accumulated):
            loss_l = []
            sample_data_l = next(train_multi_data_loader)
            for j, (sample_data, ctx) in enumerate(zip(sample_data_l, ctx_l)):
                src_token_ids, tgt_token_ids, src_valid_length,\
                tgt_valid_length, sample_ids = sample_data
                src_token_ids = src_token_ids.as_in_ctx(ctx)
                tgt_token_ids = tgt_token_ids.as_in_ctx(ctx)
                src_valid_length = src_valid_length.as_in_ctx(ctx)
                tgt_valid_length = tgt_valid_length.as_in_ctx(ctx)
                src_wc, tgt_wc, bs = src_valid_length.sum(), \
                                     tgt_valid_length.sum(), src_token_ids.shape[0]
                log_wc_l[j] += src_wc + tgt_wc
                log_tgt_wc_l[j] += tgt_wc
                token_count = (tgt_valid_length - 1).sum()
                loss_denom_l[j] += token_count / const_scale
                log_avg_loss_denom_l[j] += token_count / const_scale
                with mx.autograd.record():
                    if model.layout == 'NT':
                        tgt_pred = model(src_token_ids, src_valid_length,
                                         tgt_token_ids[:, :-1],
                                         tgt_valid_length - 1)
                        tgt_labels = tgt_token_ids[:, 1:]
                        loss = label_smooth_loss(tgt_pred, tgt_labels)
                        loss = mx.npx.sequence_mask(
                            loss,
                            sequence_length=tgt_valid_length - 1,
                            use_sequence_length=True,
                            axis=1)
                        loss = loss.sum() / const_scale
                        loss_l.append(loss)
                    elif model.layout == 'TN':
                        tgt_pred = model(src_token_ids.T, src_valid_length,
                                         tgt_token_ids.T[:-1, :],
                                         tgt_valid_length - 1)
                        tgt_labels = tgt_token_ids.T[1:, :]
                        loss = label_smooth_loss(tgt_pred, tgt_labels)
                        loss = mx.npx.sequence_mask(
                            loss,
                            sequence_length=tgt_valid_length - 1,
                            use_sequence_length=True,
                            axis=0)
                        loss = loss.sum() / const_scale
                        loss_l.append(loss)
                log_avg_loss_l[j] += loss
            if use_amp:
                with mx.autograd.record():
                    with amp.scale_loss(loss_l, trainer) as amp_loss_l:
                        for loss in amp_loss_l:
                            loss.backward()
            else:
                with mx.autograd.record():
                    for loss in loss_l:
                        loss.backward()

        # Print the total number of parameters
        if local_rank == 0 and num_params is None:
            num_params, num_fixed_params = count_parameters(param_dict)
            logging.info(
                'Total Number of Parameters (not-fixed/fixed): {}/{}'.format(
                    num_params, num_fixed_params))
        # All-Reduce the gradient
        trainer.allreduce_grads()
        if args.comm_backend == 'horovod':
            # All-Reduce the loss denominator
            assert len(loss_denom_l) == 1
            loss_denom = hvd.allreduce(loss_denom_l[0],
                                       average=False).asnumpy()
        else:
            loss_denom = sum([ele.asnumpy() for ele in loss_denom_l])
        if use_amp:
            # We need to first unscale the gradient and then perform allreduce.
            grad_scale = trainer.amp_loss_scale * loss_denom
        else:
            grad_scale = loss_denom
        if args.max_grad_norm is not None:
            total_norm, ratio, is_finite\
                = clip_grad_global_norm(params, args.max_grad_norm * grad_scale)
            total_norm = total_norm / grad_scale
        else:
            total_norm = grad_global_norm(params)
            total_norm = total_norm / grad_scale
        log_avg_grad_norm += total_norm
        log_iter_num += 1

        trainer.update(loss_denom, ignore_stale_grad=True)

        if avg_start_iter > 0 and train_iter >= avg_start_iter:
            model_averager.step()

        if ((train_iter + 1) % args.log_interval == 0
                or train_iter + 1 == total_train_iters):
            if args.comm_backend == 'horovod':
                # Use allreduce to get the total number of tokens and loss
                log_wc = hvd.allreduce(log_wc_l[0], average=False).asnumpy()
                log_tgt_wc = hvd.allreduce(log_tgt_wc_l[0],
                                           average=False).asnumpy()
                log_avg_loss = hvd.allreduce(log_avg_loss_l[0] /
                                             log_avg_loss_denom_l[0],
                                             average=True)
                log_avg_loss = log_avg_loss.asnumpy()
            else:
                log_wc = sum([ele.asnumpy() for ele in log_wc_l])
                log_tgt_wc = sum([ele.asnumpy() for ele in log_tgt_wc_l])
                log_avg_loss =\
                    sum([log_avg_loss_l[i].asnumpy() / log_avg_loss_denom_l[i].asnumpy()
                         for i in range(len(log_avg_loss_l))]) / len(log_avg_loss_l)
            log_avg_grad_norm = log_avg_grad_norm / log_iter_num
            log_end_time = time.time()
            wps = log_wc / (log_end_time - log_start_time)
            epoch_id = train_iter // num_updates_per_epoch
            logging.info(
                '[Epoch {} Iter {}/{}, Overall {}/{}] loss={:.4f}, ppl={:.4f}, '
                'throughput={:.2f}K wps, total wc={:.2f}K, wpb={:.2f}K,'
                ' LR={}, gnorm={:.4f}, ETA={:.2f}h'.format(
                    epoch_id, train_iter % num_updates_per_epoch + 1,
                    num_updates_per_epoch,
                    train_iter + 1, total_train_iters, log_avg_loss,
                    np.exp(log_avg_loss), wps / 1000, log_wc / 1000,
                    log_tgt_wc / 1000 / log_iter_num, trainer.learning_rate,
                    log_avg_grad_norm,
                    (log_end_time - train_start_time) / (train_iter + 1) *
                    (total_train_iters - train_iter - 1) / 3600))
            if local_rank == 0:
                writer.add_scalar('throughput_wps', wps, train_iter)
                writer.add_scalar('train_loss', log_avg_loss, train_iter)
                writer.add_scalar('lr', trainer.learning_rate, train_iter)
                writer.add_scalar('grad_norm', log_avg_grad_norm, train_iter)
            # Reinitialize the log variables
            log_start_time = time.time()
            log_avg_loss_l = [mx.np.array(0.0, ctx=ctx) for ctx in ctx_l]
            log_avg_loss_denom_l = [mx.np.array(0.0, ctx=ctx) for ctx in ctx_l]
            log_avg_grad_norm = 0
            log_iter_num = 0
            log_wc_l = [
                mx.np.array(0, dtype=np.int64, ctx=ctx) for ctx in ctx_l
            ]
            log_tgt_wc_l = [
                mx.np.array(0, dtype=np.int64, ctx=ctx) for ctx in ctx_l
            ]

        if (args.max_update > 0 and (train_iter + 1) % args.save_interval_update == 0) \
            or ((train_iter + 1) % num_updates_per_epoch == 0) \
            or train_iter + 1 == total_train_iters:
            epoch_id = (train_iter + 1) // num_updates_per_epoch
            if local_rank == 0:
                if args.max_update <= 0:
                    model.save_parameters(os.path.join(
                        args.save_dir, 'epoch{}.params'.format(epoch_id)),
                                          deduplicate=True)
                else:
                    model.save_parameters(os.path.join(
                        args.save_dir, 'iter{}.params'.format(train_iter + 1)),
                                          deduplicate=True)

            avg_val_loss, ntokens, pred_sentences, pred_lengths, sentence_ids\
                = validation(model, val_data_loader, inference_model, beam_search_sampler,
                             tgt_tokenizer, ctx_l)
            if args.comm_backend == 'horovod':
                flatten_pred_sentences = np.concatenate(pred_sentences, axis=0)
                all_val_loss = hvd.allgather(
                    mx.np.array([avg_val_loss * ntokens],
                                dtype=np.float32,
                                ctx=ctx_l[0]))
                all_ntokens = hvd.allgather(
                    mx.np.array([ntokens], dtype=np.int64, ctx=ctx_l[0]))
                flatten_pred_sentences = hvd.allgather(
                    mx.np.array(flatten_pred_sentences,
                                dtype=np.int32,
                                ctx=ctx_l[0]))
                pred_lengths = hvd.allgather(
                    mx.np.array(pred_lengths, dtype=np.int64, ctx=ctx_l[0]))
                sentence_ids = hvd.allgather(
                    mx.np.array(sentence_ids, dtype=np.int64, ctx=ctx_l[0]))
                avg_val_loss = all_val_loss.asnumpy().sum(
                ) / all_ntokens.asnumpy().sum()
                flatten_pred_sentences = flatten_pred_sentences.asnumpy()
                pred_lengths = pred_lengths.asnumpy()
                sentence_ids = sentence_ids.asnumpy()
                pred_sentences = [None for _ in range(len(sentence_ids))]
                ptr = 0
                assert sentence_ids.min() == 0 and sentence_ids.max(
                ) == len(sentence_ids) - 1
                for sentence_id, length in zip(sentence_ids, pred_lengths):
                    pred_sentences[sentence_id] = flatten_pred_sentences[ptr:(
                        ptr + length)]
                    ptr += length
            if local_rank == 0:
                # Perform detokenization
                pred_sentences_bpe_decode = []
                pred_sentences_raw = []
                for sentence in pred_sentences:
                    bpe_decode_sentence = tgt_tokenizer.decode(
                        sentence.tolist())
                    raw_sentence = base_tgt_tokenizer.decode(
                        bpe_decode_sentence.split())
                    pred_sentences_bpe_decode.append(bpe_decode_sentence)
                    pred_sentences_raw.append(raw_sentence)
                detok_sacrebleu_out = sacrebleu.corpus_bleu(
                    sys_stream=pred_sentences_bpe_decode,
                    ref_streams=[tgt_detok_sentences])
                raw_sacrebleu_out = sacrebleu.corpus_bleu(
                    sys_stream=pred_sentences_raw,
                    ref_streams=[tgt_raw_sentences])
                with open(
                        os.path.join(args.save_dir,
                                     f'epoch{epoch_id}_dev_prediction.txt'),
                        'w') as of:
                    for line in pred_sentences_raw:
                        of.write(line + '\n')
                logging.info(
                    '[Epoch {}][Iter {}/{}] validation loss/ppl={:.4f}/{:.4f}, '
                    'SacreBlEU={}, Detok SacreBLUE={}'.format(
                        epoch_id, train_iter, total_train_iters, avg_val_loss,
                        np.exp(avg_val_loss), raw_sacrebleu_out.score,
                        detok_sacrebleu_out.score))
                writer.add_scalar('valid_loss', avg_val_loss, train_iter)
                writer.add_scalar('valid_bleu', raw_sacrebleu_out.score,
                                  train_iter)

    if args.num_averages > 0:
        model_averager.copy_back(
            param_dict)  # TODO(sxjscience) Rewrite using update
        model.save_parameters(os.path.join(args.save_dir, 'average.params'),
                              deduplicate=True)