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+## Transformer
+
+以下是本例的简要目录结构及说明：
+
+```text
+.
+├── images               # README 文档中的图片
+├── utils                # 工具包
+├── gen_data.sh          # 数据生成脚本
+├── predict.py           # 预测脚本
+├── reader.py            # 数据读取接口
+├── README.md            # 文档
+├── train.py             # 训练脚本
+├── model.py             # 模型定义文件
+└── transformer.yaml     # 配置文件
+```
+
+## 模型简介
+
+机器翻译（machine translation, MT）是利用计算机将一种自然语言(源语言)转换为另一种自然语言(目标语言)的过程，输入为源语言句子，输出为相应的目标语言的句子。
+
+本项目是机器翻译领域主流模型 Transformer 的 PaddlePaddle 实现， 包含模型训练，预测以及使用自定义数据等内容。用户可以基于发布的内容搭建自己的翻译模型。
+
+
+## 快速开始
+
+### 安装说明
+
+1. paddle安装
+
+   本项目依赖于 PaddlePaddle 1.7及以上版本或适当的develop版本，请参考 [安装指南](http://www.paddlepaddle.org/#quick-start) 进行安装
+
+2. 下载代码
+
+    克隆代码库到本地
+    ```shell
+    git clone https://github.com/PaddlePaddle/models.git
+    cd models/dygraph/transformer
+    ```
+
+3. 环境依赖
+
+   请参考PaddlePaddle[安装说明](https://www.paddlepaddle.org.cn/documentation/docs/zh/1.6/beginners_guide/install/index_cn.html)部分的内容
+
+
+### 数据准备
+
+公开数据集：WMT 翻译大赛是机器翻译领域最具权威的国际评测大赛，其中英德翻译任务提供了一个中等规模的数据集，这个数据集是较多论文中使用的数据集，也是 Transformer 论文中用到的一个数据集。我们也将[WMT'16 EN-DE 数据集](http://www.statmt.org/wmt16/translation-task.html)作为示例提供。运行 `gen_data.sh` 脚本进行 WMT'16 EN-DE 数据集的下载和预处理（时间较长，建议后台运行）。数据处理过程主要包括 Tokenize 和 [BPE 编码（byte-pair encoding）](https://arxiv.org/pdf/1508.07909)。运行成功后，将会生成文件夹 `gen_data`，其目录结构如下：
+
+```text
+.
+├── wmt16_ende_data              # WMT16 英德翻译数据
+├── wmt16_ende_data_bpe          # BPE 编码的 WMT16 英德翻译数据
+├── mosesdecoder                 # Moses 机器翻译工具集，包含了 Tokenize、BLEU 评估等脚本
+└── subword-nmt                  # BPE 编码的代码
+```
+
+另外我们也整理提供了一份处理好的 WMT'16 EN-DE 数据以供[下载](https://transformer-res.bj.bcebos.com/wmt16_ende_data_bpe_clean.tar.gz)使用，其中包含词典（`vocab_all.bpe.32000`文件）、训练所需的 BPE 数据（`train.tok.clean.bpe.32000.en-de`文件）、预测所需的 BPE 数据（`newstest2016.tok.bpe.32000.en-de`等文件）和相应的评估预测结果所需的 tokenize 数据（`newstest2016.tok.de`等文件）。
+
+
+自定义数据：如果需要使用自定义数据，本项目程序中可直接支持的数据格式为制表符 \t 分隔的源语言和目标语言句子对，句子中的 token 之间使用空格分隔。提供以上格式的数据文件（可以分多个part，数据读取支持文件通配符）和相应的词典文件即可直接运行。
+
+### 单机训练
+
+### 单机单卡
+
+以提供的英德翻译数据为例，可以执行以下命令进行模型训练：
+
+```sh
+# setting visible devices for training
+export CUDA_VISIBLE_DEVICES=0
+
+python -u train.py \
+  --epoch 30 \
+  --src_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --trg_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --special_token '<s>' '<e>' '<unk>' \
+  --training_file gen_data/wmt16_ende_data_bpe/train.tok.clean.bpe.32000.en-de \
+  --validation_file gen_data/wmt16_ende_data_bpe/newstest2014.tok.bpe.32000.en-de \
+  --batch_size 4096
+```
+
+以上命令中传入了训练轮数（`epoch`）和训练数据文件路径（注意请正确设置，支持通配符）等参数，更多参数的使用以及支持的模型超参数可以参见 `transformer.yaml` 配置文件，其中默认提供了 Transformer base model 的配置，如需调整可以在配置文件中更改或通过命令行传入（命令行传入内容将覆盖配置文件中的设置）。可以通过以下命令来训练 Transformer 论文中的 big model：
+
+```sh
+# setting visible devices for training
+export CUDA_VISIBLE_DEVICES=0
+
+python -u train.py \
+  --epoch 30 \
+  --src_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --trg_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --special_token '<s>' '<e>' '<unk>' \
+  --training_file gen_data/wmt16_ende_data_bpe/train.tok.clean.bpe.32000.en-de \
+  --validation_file gen_data/wmt16_ende_data_bpe/newstest2014.tok.bpe.32000.en-de \
+  --batch_size 4096 \
+  --n_head 16 \
+  --d_model 1024 \
+  --d_inner_hid 4096 \
+  --prepostprocess_dropout 0.3
+```
+
+另外，如果在执行训练时若提供了 `save_model`（默认为 trained_models），则每隔一定 iteration 后（通过参数 `save_step` 设置，默认为10000）将保存当前训练的到相应目录（会保存分别记录了模型参数和优化器状态的 `transformer.pdparams` 和 `transformer.pdopt` 两个文件），每隔一定数目的 iteration (通过参数 `print_step` 设置，默认为100)将打印如下的日志到标准输出：
+
+```txt
+[2019-08-02 15:30:51,656 INFO train.py:262] step_idx: 150100, epoch: 32, batch: 1364, avg loss: 2.880427, normalized loss: 1.504687, ppl: 17.821888, speed: 3.34 step/s
+[2019-08-02 15:31:19,824 INFO train.py:262] step_idx: 150200, epoch: 32, batch: 1464, avg loss: 2.955965, normalized loss: 1.580225, ppl: 19.220257, speed: 3.55 step/s
+[2019-08-02 15:31:48,151 INFO train.py:262] step_idx: 150300, epoch: 32, batch: 1564, avg loss: 2.951180, normalized loss: 1.575439, ppl: 19.128502, speed: 3.53 step/s
+[2019-08-02 15:32:16,401 INFO train.py:262] step_idx: 150400, epoch: 32, batch: 1664, avg loss: 3.027281, normalized loss: 1.651540, ppl: 20.641024, speed: 3.54 step/s
+[2019-08-02 15:32:44,764 INFO train.py:262] step_idx: 150500, epoch: 32, batch: 1764, avg loss: 3.069125, normalized loss: 1.693385, ppl: 21.523066, speed: 3.53 step/s
+[2019-08-02 15:33:13,199 INFO train.py:262] step_idx: 150600, epoch: 32, batch: 1864, avg loss: 2.869379, normalized loss: 1.493639, ppl: 17.626074, speed: 3.52 step/s
+[2019-08-02 15:33:41,601 INFO train.py:262] step_idx: 150700, epoch: 32, batch: 1964, avg loss: 2.980905, normalized loss: 1.605164, ppl: 19.705633, speed: 3.52 step/s
+[2019-08-02 15:34:10,079 INFO train.py:262] step_idx: 150800, epoch: 32, batch: 2064, avg loss: 3.047716, normalized loss: 1.671976, ppl: 21.067181, speed: 3.51 step/s
+[2019-08-02 15:34:38,598 INFO train.py:262] step_idx: 150900, epoch: 32, batch: 2164, avg loss: 2.956475, normalized loss: 1.580735, ppl: 19.230072, speed: 3.51 step/s
+```
+
+也可以使用 CPU 训练(通过参数 `--use_cuda False` 设置)，训练速度较慢。
+
+#### 单机多卡
+
+Paddle动态图支持多进程多卡进行模型训练，启动训练的方式如下：
+
+```sh
+python -m paddle.distributed.launch --started_port 8999 --selected_gpus=0,1,2,3,4,5,6,7 --log_dir ./mylog train.py \
+  --epoch 30 \
+  --src_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --trg_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --special_token '<s>' '<e>' '<unk>' \
+  --training_file gen_data/wmt16_ende_data_bpe/train.tok.clean.bpe.32000.en-de \
+  --validation_file gen_data/wmt16_ende_data_bpe/newstest2014.tok.bpe.32000.en-de \
+  --batch_size 4096 \
+  --print_step 100 \
+  --use_cuda True \
+  --save_step 10000
+```
+
+此时，程序会将每个进程的输出log导入到`./mylog`路径下，只有第一个工作进程会保存模型。
+
+```
+.
+├── mylog
+│   ├── workerlog.0
+│   ├── workerlog.1
+│   ├── workerlog.2
+│   ├── workerlog.3
+│   ├── workerlog.4
+│   ├── workerlog.5
+│   ├── workerlog.6
+│   └── workerlog.7
+```
+
+### 模型推断
+
+以英德翻译数据为例，模型训练完成后可以执行以下命令对指定文件中的文本进行翻译：
+
+```sh
+# setting visible devices for prediction
+export CUDA_VISIBLE_DEVICES=0
+
+python -u predict.py \
+  --src_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --trg_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --special_token '<s>' '<e>' '<unk>' \
+  --predict_file gen_data/wmt16_ende_data_bpe/newstest2014.tok.bpe.32000.en-de \
+  --batch_size 32 \
+  --init_from_params trained_params/step_100000 \
+  --beam_size 5 \
+  --max_out_len 255 \
+  --output_file predict.txt
+```
+
+ 由 `predict_file` 指定的文件中文本的翻译结果会输出到 `output_file` 指定的文件。执行预测时需要设置 `init_from_params` 来给出模型所在目录，更多参数的使用可以在 `transformer.yaml` 文件中查阅注释说明并进行更改设置。注意若在执行预测时设置了模型超参数，应与模型训练时的设置一致，如若训练时使用 big model 的参数设置，则预测时对应类似如下命令：
+
+```sh
+# setting visible devices for prediction
+export CUDA_VISIBLE_DEVICES=0
+
+python -u predict.py \
+  --src_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --trg_vocab_fpath gen_data/wmt16_ende_data_bpe/vocab_all.bpe.32000 \
+  --special_token '<s>' '<e>' '<unk>' \
+  --predict_file gen_data/wmt16_ende_data_bpe/newstest2014.tok.bpe.32000.en-de \
+  --batch_size 32 \
+  --init_from_params trained_params/step_100000 \
+  --beam_size 5 \
+  --max_out_len 255 \
+  --output_file predict.txt \
+  --n_head 16 \
+  --d_model 1024 \
+  --d_inner_hid 4096 \
+  --prepostprocess_dropout 0.3
+```
+
+
+### 模型评估
+
+预测结果中每行输出是对应行输入的得分最高的翻译，对于使用 BPE 的数据，预测出的翻译结果也将是 BPE 表示的数据，要还原成原始的数据（这里指 tokenize 后的数据）才能进行正确的评估。评估过程具体如下（BLEU 是翻译任务常用的自动评估方法指标）：
+
+```sh
+# 还原 predict.txt 中的预测结果为 tokenize 后的数据
+sed -r 's/(@@ )|(@@ ?$)//g' predict.txt > predict.tok.txt
+# 若无 BLEU 评估工具，需先进行下载
+# git clone https://github.com/moses-smt/mosesdecoder.git
+# 以英德翻译 newstest2014 测试数据为例
+perl gen_data/mosesdecoder/scripts/generic/multi-bleu.perl gen_data/wmt16_ende_data/newstest2014.tok.de < predict.tok.txt
+```
+可以看到类似如下的结果：
+```
+BLEU = 26.35, 57.7/32.1/20.0/13.0 (BP=1.000, ratio=1.013, hyp_len=63903, ref_len=63078)
+```
+
+使用本项目中提供的内容，英德翻译 base model 和 big model 八卡训练 100K 个 iteration 后测试有大约如下的 BLEU 值：
+
+| 测试集 | newstest2014 | newstest2015 | newstest2016 |
+|-|-|-|-|
+| Base | 26.35 | 29.07 | 33.30 |
+| Big | 27.07 | 30.09 | 34.38 |
+
+### 预训练模型
+
+我们这里提供了对应有以上 BLEU 值的 [base model](https://transformer-res.bj.bcebos.com/base_model_dygraph.tar.gz) 和 [big model](https://transformer-res.bj.bcebos.com/big_model_dygraph.tar.gz) 的模型参数提供下载使用（注意，模型使用了提供下载的数据进行训练和测试）。
+
+## 进阶使用
+
+### 背景介绍
+
+Transformer 是论文 [Attention Is All You Need](https://arxiv.org/abs/1706.03762) 中提出的用以完成机器翻译（machine translation, MT）等序列到序列（sequence to sequence, Seq2Seq）学习任务的一种全新网络结构，其完全使用注意力（Attention）机制来实现序列到序列的建模[1]。
+
+相较于此前 Seq2Seq 模型中广泛使用的循环神经网络（Recurrent Neural Network, RNN），使用（Self）Attention 进行输入序列到输出序列的变换主要具有以下优势：
+
+- 计算复杂度小
+  - 特征维度为 d 、长度为 n 的序列，在 RNN 中计算复杂度为 `O(n * d * d)` （n 个时间步，每个时间步计算 d 维的矩阵向量乘法），在 Self-Attention 中计算复杂度为 `O(n * n * d)` （n 个时间步两两计算 d 维的向量点积或其他相关度函数），n 通常要小于 d 。
+- 计算并行度高
+  - RNN 中当前时间步的计算要依赖前一个时间步的计算结果；Self-Attention 中各时间步的计算只依赖输入不依赖之前时间步输出，各时间步可以完全并行。
+- 容易学习长程依赖（long-range dependencies）
+  - RNN 中相距为 n 的两个位置间的关联需要 n 步才能建立；Self-Attention 中任何两个位置都直接相连；路径越短信号传播越容易。
+
+Transformer 中引入使用的基于 Self-Attention 的序列建模模块结构，已被广泛应用在 Bert [2]等语义表示模型中，取得了显著效果。
+
+
+### 模型概览
+
+Transformer 同样使用了 Seq2Seq 模型中典型的编码器-解码器（Encoder-Decoder）的框架结构，整体网络结构如图1所示。
+
+<p align="center">
+<img src="images/transformer_network.png" height=400 hspace='10'/> <br />
+图 1. Transformer 网络结构图
+</p>
+
+可以看到，和以往 Seq2Seq 模型不同，Transformer 的 Encoder 和 Decoder 中不再使用 RNN 的结构。
+
+### 模型特点
+
+Transformer 中的 Encoder 由若干相同的 layer 堆叠组成，每个 layer 主要由多头注意力（Multi-Head Attention）和全连接的前馈（Feed-Forward）网络这两个 sub-layer 构成。
+- Multi-Head Attention 在这里用于实现 Self-Attention，相比于简单的 Attention 机制，其将输入进行多路线性变换后分别计算 Attention 的结果，并将所有结果拼接后再次进行线性变换作为输出。参见图2，其中 Attention 使用的是点积（Dot-Product），并在点积后进行了 scale 的处理以避免因点积结果过大进入 softmax 的饱和区域。
+- Feed-Forward 网络会对序列中的每个位置进行相同的计算（Position-wise），其采用的是两次线性变换中间加以 ReLU 激活的结构。
+
+此外，每个 sub-layer 后还施以 Residual Connection [3]和 Layer Normalization [4]来促进梯度传播和模型收敛。
+
+<p align="center">
+<img src="images/multi_head_attention.png" height=300 hspace='10'/> <br />
+图 2. Multi-Head Attention
+</p>
+
+Decoder 具有和 Encoder 类似的结构，只是相比于组成 Encoder 的 layer ，在组成 Decoder 的 layer 中还多了一个 Multi-Head Attention 的 sub-layer 来实现对 Encoder 输出的 Attention，这个 Encoder-Decoder Attention 在其他 Seq2Seq 模型中也是存在的。
+
+## FAQ
+
+**Q:** 预测结果中样本数少于输入的样本数是什么原因  
+**A:** 若样本中最大长度超过 `transformer.yaml` 中 `max_length` 的默认设置，请注意运行时增大 `--max_length` 的设置，否则超长样本将被过滤。
+
+**Q:** 预测时最大长度超过了训练时的最大长度怎么办  
+**A:** 由于训练时 `max_length` 的设置决定了保存模型 position encoding 的大小，若预测时长度超过 `max_length`，请调大该值，会重新生成更大的 position encoding 表。
+
+
+## 参考文献
+1. Vaswani A, Shazeer N, Parmar N, et al. [Attention is all you need](http://papers.nips.cc/paper/7181-attention-is-all-you-need.pdf)[C]//Advances in Neural Information Processing Systems. 2017: 6000-6010.
+2. Devlin J, Chang M W, Lee K, et al. [Bert: Pre-training of deep bidirectional transformers for language understanding](https://arxiv.org/abs/1810.04805)[J]. arXiv preprint arXiv:1810.04805, 2018.
+3. He K, Zhang X, Ren S, et al. [Deep residual learning for image recognition](http://openaccess.thecvf.com/content_cvpr_2016/papers/He_Deep_Residual_Learning_CVPR_2016_paper.pdf)[C]//Proceedings of the IEEE conference on computer vision and pattern recognition. 2016: 770-778.
+4. Ba J L, Kiros J R, Hinton G E. [Layer normalization](https://arxiv.org/pdf/1607.06450.pdf)[J]. arXiv preprint arXiv:1607.06450, 2016.
+5. Sennrich R, Haddow B, Birch A. [Neural machine translation of rare words with subword units](https://arxiv.org/pdf/1508.07909)[J]. arXiv preprint arXiv:1508.07909, 2015.
+
+
+## 作者
+- [guochengCS](https://github.com/guoshengCS)
+
+## 如何贡献代码
+
+如果你可以修复某个issue或者增加一个新功能，欢迎给我们提交PR。如果对应的PR被接受了，我们将根据贡献的质量和难度进行打分（0-5分，越高越好）。如果你累计获得了10分，可以联系我们获得面试机会或者为你写推荐信。
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diff --git a/transformer/predict.py b/transformer/predict.py
new file mode 100644
index 0000000000000000000000000000000000000000..d33d4e5c909d9565dccbddaf3181e5a0b56c0d88
--- /dev/null
+++ b/transformer/predict.py
@@ -0,0 +1,143 @@
+# Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+import os
+import six
+import sys
+import time
+
+import numpy as np
+import paddle
+import paddle.fluid as fluid
+
+from utils.configure import PDConfig
+from utils.check import check_gpu, check_version
+
+# include task-specific libs
+import reader
+from model import Transformer, position_encoding_init
+
+
+def post_process_seq(seq, bos_idx, eos_idx, output_bos=False, output_eos=False):
+    """
+    Post-process the decoded sequence.
+    """
+    eos_pos = len(seq) - 1
+    for i, idx in enumerate(seq):
+        if idx == eos_idx:
+            eos_pos = i
+            break
+    seq = [
+        idx for idx in seq[:eos_pos + 1]
+        if (output_bos or idx != bos_idx) and (output_eos or idx != eos_idx)
+    ]
+    return seq
+
+
+def do_predict(args):
+    if args.use_cuda:
+        place = fluid.CUDAPlace(0)
+    else:
+        place = fluid.CPUPlace()
+
+    # define the data generator
+    processor = reader.DataProcessor(fpattern=args.predict_file,
+                                     src_vocab_fpath=args.src_vocab_fpath,
+                                     trg_vocab_fpath=args.trg_vocab_fpath,
+                                     token_delimiter=args.token_delimiter,
+                                     use_token_batch=False,
+                                     batch_size=args.batch_size,
+                                     device_count=1,
+                                     pool_size=args.pool_size,
+                                     sort_type=reader.SortType.NONE,
+                                     shuffle=False,
+                                     shuffle_batch=False,
+                                     start_mark=args.special_token[0],
+                                     end_mark=args.special_token[1],
+                                     unk_mark=args.special_token[2],
+                                     max_length=args.max_length,
+                                     n_head=args.n_head)
+    batch_generator = processor.data_generator(phase="predict", place=place)
+    args.src_vocab_size, args.trg_vocab_size, args.bos_idx, args.eos_idx, \
+        args.unk_idx = processor.get_vocab_summary()
+    trg_idx2word = reader.DataProcessor.load_dict(
+        dict_path=args.trg_vocab_fpath, reverse=True)
+
+    args.src_vocab_size, args.trg_vocab_size, args.bos_idx, args.eos_idx, \
+        args.unk_idx = processor.get_vocab_summary()
+
+    with fluid.dygraph.guard(place):
+        # define data loader
+        test_loader = fluid.io.DataLoader.from_generator(capacity=10)
+        test_loader.set_batch_generator(batch_generator, places=place)
+
+        # define model
+        transformer = Transformer(
+            args.src_vocab_size, args.trg_vocab_size, args.max_length + 1,
+            args.n_layer, args.n_head, args.d_key, args.d_value, args.d_model,
+            args.d_inner_hid, args.prepostprocess_dropout,
+            args.attention_dropout, args.relu_dropout, args.preprocess_cmd,
+            args.postprocess_cmd, args.weight_sharing, args.bos_idx,
+            args.eos_idx)
+
+        # load the trained model
+        assert args.init_from_params, (
+            "Please set init_from_params to load the infer model.")
+        model_dict, _ = fluid.load_dygraph(
+            os.path.join(args.init_from_params, "transformer"))
+        # to avoid a longer length than training, reset the size of position
+        # encoding to max_length
+        model_dict["encoder.pos_encoder.weight"] = position_encoding_init(
+            args.max_length + 1, args.d_model)
+        model_dict["decoder.pos_encoder.weight"] = position_encoding_init(
+            args.max_length + 1, args.d_model)
+        transformer.load_dict(model_dict)
+
+        # set evaluate mode
+        transformer.eval()
+
+        f = open(args.output_file, "wb")
+        for input_data in test_loader():
+            (src_word, src_pos, src_slf_attn_bias, trg_word,
+             trg_src_attn_bias) = input_data
+            finished_seq, finished_scores = transformer.beam_search(
+                src_word,
+                src_pos,
+                src_slf_attn_bias,
+                trg_word,
+                trg_src_attn_bias,
+                bos_id=args.bos_idx,
+                eos_id=args.eos_idx,
+                beam_size=args.beam_size,
+                max_len=args.max_out_len)
+            finished_seq = finished_seq.numpy()
+            finished_scores = finished_scores.numpy()
+            for ins in finished_seq:
+                for beam_idx, beam in enumerate(ins):
+                    if beam_idx >= args.n_best: break
+                    id_list = post_process_seq(beam, args.bos_idx, args.eos_idx)
+                    word_list = [trg_idx2word[id] for id in id_list]
+                    sequence = b" ".join(word_list) + b"\n"
+                    f.write(sequence)
+
+
+if __name__ == "__main__":
+    args = PDConfig(yaml_file="./transformer.yaml")
+    args.build()
+    args.Print()
+    check_gpu(args.use_cuda)
+    check_version()
+
+    do_predict(args)
diff --git a/transformer/reader.py b/transformer/reader.py
new file mode 100644
index 0000000000000000000000000000000000000000..ef23c5e1e32fa4cee1ba5a42bb970a1a135879a0
--- /dev/null
+++ b/transformer/reader.py
@@ -0,0 +1,550 @@
+# Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import glob
+import six
+import os
+import tarfile
+
+import numpy as np
+import paddle.fluid as fluid
+
+
+def pad_batch_data(insts,
+                   pad_idx,
+                   n_head,
+                   is_target=False,
+                   is_label=False,
+                   return_attn_bias=True,
+                   return_max_len=True,
+                   return_num_token=False):
+    """
+    Pad the instances to the max sequence length in batch, and generate the
+    corresponding position data and attention bias.
+    """
+    return_list = []
+    max_len = max(len(inst) for inst in insts)
+    # Any token included in dict can be used to pad, since the paddings' loss
+    # will be masked out by weights and make no effect on parameter gradients.
+    inst_data = np.array(
+        [inst + [pad_idx] * (max_len - len(inst)) for inst in insts])
+    return_list += [inst_data.astype("int64").reshape([-1, 1])]
+    if is_label:  # label weight
+        inst_weight = np.array([[1.] * len(inst) + [0.] * (max_len - len(inst))
+                                for inst in insts])
+        return_list += [inst_weight.astype("float32").reshape([-1, 1])]
+    else:  # position data
+        inst_pos = np.array([
+            list(range(0, len(inst))) + [0] * (max_len - len(inst))
+            for inst in insts
+        ])
+        return_list += [inst_pos.astype("int64").reshape([-1, 1])]
+    if return_attn_bias:
+        if is_target:
+            # This is used to avoid attention on paddings and subsequent
+            # words.
+            slf_attn_bias_data = np.ones((inst_data.shape[0], max_len, max_len))
+            slf_attn_bias_data = np.triu(slf_attn_bias_data,
+                                         1).reshape([-1, 1, max_len, max_len])
+            slf_attn_bias_data = np.tile(slf_attn_bias_data,
+                                         [1, n_head, 1, 1]) * [-1e9]
+        else:
+            # This is used to avoid attention on paddings.
+            slf_attn_bias_data = np.array([[0] * len(inst) + [-1e9] *
+                                           (max_len - len(inst))
+                                           for inst in insts])
+            slf_attn_bias_data = np.tile(
+                slf_attn_bias_data.reshape([-1, 1, 1, max_len]),
+                [1, n_head, max_len, 1])
+        return_list += [slf_attn_bias_data.astype("float32")]
+    if return_max_len:
+        return_list += [max_len]
+    if return_num_token:
+        num_token = 0
+        for inst in insts:
+            num_token += len(inst)
+        return_list += [num_token]
+    return return_list if len(return_list) > 1 else return_list[0]
+
+
+def prepare_train_input(insts, src_pad_idx, trg_pad_idx, n_head):
+    """
+    Put all padded data needed by training into a list.
+    """
+    src_word, src_pos, src_slf_attn_bias, src_max_len = pad_batch_data(
+        [inst[0] for inst in insts], src_pad_idx, n_head, is_target=False)
+    src_word = src_word.reshape(-1, src_max_len)
+    src_pos = src_pos.reshape(-1, src_max_len)
+    trg_word, trg_pos, trg_slf_attn_bias, trg_max_len = pad_batch_data(
+        [inst[1] for inst in insts], trg_pad_idx, n_head, is_target=True)
+    trg_word = trg_word.reshape(-1, trg_max_len)
+    trg_pos = trg_pos.reshape(-1, trg_max_len)
+
+    trg_src_attn_bias = np.tile(src_slf_attn_bias[:, :, ::src_max_len, :],
+                                [1, 1, trg_max_len, 1]).astype("float32")
+
+    lbl_word, lbl_weight, num_token = pad_batch_data(
+        [inst[2] for inst in insts],
+        trg_pad_idx,
+        n_head,
+        is_target=False,
+        is_label=True,
+        return_attn_bias=False,
+        return_max_len=False,
+        return_num_token=True)
+    lbl_word = lbl_word.reshape(-1, 1)
+    lbl_weight = lbl_weight.reshape(-1, 1)
+
+    data_inputs = [
+        src_word, src_pos, src_slf_attn_bias, trg_word, trg_pos,
+        trg_slf_attn_bias, trg_src_attn_bias, lbl_word, lbl_weight
+    ]
+
+    return data_inputs
+
+
+def prepare_infer_input(insts, src_pad_idx, bos_idx, n_head, place):
+    """
+    Put all padded data needed by beam search decoder into a list.
+    """
+    src_word, src_pos, src_slf_attn_bias, src_max_len = pad_batch_data(
+        [inst[0] for inst in insts], src_pad_idx, n_head, is_target=False)
+    # start tokens
+    trg_word = np.asarray([[bos_idx]] * len(insts), dtype="int64")
+    trg_src_attn_bias = np.tile(src_slf_attn_bias[:, :, ::src_max_len, :],
+                                [1, 1, 1, 1]).astype("float32")
+    trg_word = trg_word.reshape(-1, 1)
+    src_word = src_word.reshape(-1, src_max_len)
+    src_pos = src_pos.reshape(-1, src_max_len)
+
+    data_inputs = [
+        src_word, src_pos, src_slf_attn_bias, trg_word, trg_src_attn_bias
+    ]
+    return data_inputs
+
+
+class SortType(object):
+    GLOBAL = 'global'
+    POOL = 'pool'
+    NONE = "none"
+
+
+class Converter(object):
+    def __init__(self, vocab, beg, end, unk, delimiter, add_beg):
+        self._vocab = vocab
+        self._beg = beg
+        self._end = end
+        self._unk = unk
+        self._delimiter = delimiter
+        self._add_beg = add_beg
+
+    def __call__(self, sentence):
+        return ([self._beg] if self._add_beg else []) + [
+            self._vocab.get(w, self._unk)
+            for w in sentence.split(self._delimiter)
+        ] + [self._end]
+
+
+class ComposedConverter(object):
+    def __init__(self, converters):
+        self._converters = converters
+
+    def __call__(self, parallel_sentence):
+        return [
+            self._converters[i](parallel_sentence[i])
+            for i in range(len(self._converters))
+        ]
+
+
+class SentenceBatchCreator(object):
+    def __init__(self, batch_size):
+        self.batch = []
+        self._batch_size = batch_size
+
+    def append(self, info):
+        self.batch.append(info)
+        if len(self.batch) == self._batch_size:
+            tmp = self.batch
+            self.batch = []
+            return tmp
+
+
+class TokenBatchCreator(object):
+    def __init__(self, batch_size):
+        self.batch = []
+        self.max_len = -1
+        self._batch_size = batch_size
+
+    def append(self, info):
+        cur_len = info.max_len
+        max_len = max(self.max_len, cur_len)
+        if max_len * (len(self.batch) + 1) > self._batch_size:
+            result = self.batch
+            self.batch = [info]
+            self.max_len = cur_len
+            return result
+        else:
+            self.max_len = max_len
+            self.batch.append(info)
+
+
+class SampleInfo(object):
+    def __init__(self, i, max_len, min_len):
+        self.i = i
+        self.min_len = min_len
+        self.max_len = max_len
+
+
+class MinMaxFilter(object):
+    def __init__(self, max_len, min_len, underlying_creator):
+        self._min_len = min_len
+        self._max_len = max_len
+        self._creator = underlying_creator
+
+    def append(self, info):
+        if info.max_len > self._max_len or info.min_len < self._min_len:
+            return
+        else:
+            return self._creator.append(info)
+
+    @property
+    def batch(self):
+        return self._creator.batch
+
+
+class DataProcessor(object):
+    """
+    The data reader loads all data from files and produces batches of data
+    in the way corresponding to settings.
+
+    An example of returning a generator producing data batches whose data
+    is shuffled in each pass and sorted in each pool:
+
+    ```
+    train_data = DataProcessor(
+        src_vocab_fpath='data/src_vocab_file',
+        trg_vocab_fpath='data/trg_vocab_file',
+        fpattern='data/part-*',
+        use_token_batch=True,
+        batch_size=2000,
+        device_count=8,
+        n_head=8,
+        pool_size=10000,
+        sort_type=SortType.POOL,
+        shuffle=True,
+        shuffle_batch=True,
+        start_mark='<s>',
+        end_mark='<e>',
+        unk_mark='<unk>',
+        clip_last_batch=False).data_generator(phase='train')
+    ```
+
+    :param src_vocab_fpath: The path of vocabulary file of source language.
+    :type src_vocab_fpath: basestring
+    :param trg_vocab_fpath: The path of vocabulary file of target language.
+    :type trg_vocab_fpath: basestring
+    :param fpattern: The pattern to match data files.
+    :type fpattern: basestring
+    :param batch_size: The number of sequences contained in a mini-batch.
+        or the maximum number of tokens (include paddings) contained in a
+        mini-batch.
+    :type batch_size: int
+    :param pool_size: The size of pool buffer.
+    :type device_count: int
+    :param device_count: The number of devices. The actual batch size is
+        determined by both batch_size and device_count.
+    :type n_head: int
+    :param n_head: The number of head used in multi-head attention. Actually,
+        this is not a reader related argument, but is used for input data.
+    :type pool_size: int
+    :param sort_type: The grain to sort by length: 'global' for all
+        instances; 'pool' for instances in pool; 'none' for no sort.
+    :type sort_type: basestring
+    :param clip_last_batch: Whether to clip the last uncompleted batch.
+    :type clip_last_batch: bool
+    :param tar_fname: The data file in tar if fpattern matches a tar file.
+    :type tar_fname: basestring
+    :param min_length: The minimum length used to filt sequences.
+    :type min_length: int
+    :param max_length: The maximum length used to filt sequences.
+    :type max_length: int
+    :param shuffle: Whether to shuffle all instances.
+    :type shuffle: bool
+    :param shuffle_batch: Whether to shuffle the generated batches.
+    :type shuffle_batch: bool
+    :param use_token_batch: Whether to produce batch data according to
+        token number.
+    :type use_token_batch: bool
+    :param field_delimiter: The delimiter used to split source and target in
+        each line of data file.
+    :type field_delimiter: basestring
+    :param token_delimiter: The delimiter used to split tokens in source or
+        target sentences.
+    :type token_delimiter: basestring
+    :param start_mark: The token representing for the beginning of
+        sentences in dictionary.
+    :type start_mark: basestring
+    :param end_mark: The token representing for the end of sentences
+        in dictionary.
+    :type end_mark: basestring
+    :param unk_mark: The token representing for unknown word in dictionary.
+    :type unk_mark: basestring
+    :param only_src: Whether each line is a source and target sentence
+        pair or only has the source sentence.
+    :type only_src: bool
+    :param seed: The seed for random.
+    :type seed: int
+    """
+    def __init__(self,
+                 src_vocab_fpath,
+                 trg_vocab_fpath,
+                 fpattern,
+                 batch_size,
+                 device_count,
+                 n_head,
+                 pool_size,
+                 sort_type=SortType.GLOBAL,
+                 clip_last_batch=False,
+                 tar_fname=None,
+                 min_length=0,
+                 max_length=100,
+                 shuffle=True,
+                 shuffle_batch=False,
+                 use_token_batch=False,
+                 field_delimiter="\t",
+                 token_delimiter=" ",
+                 start_mark="<s>",
+                 end_mark="<e>",
+                 unk_mark="<unk>",
+                 only_src=False,
+                 seed=0):
+        # convert str to bytes, and use byte data
+        field_delimiter = field_delimiter.encode("utf8")
+        token_delimiter = token_delimiter.encode("utf8")
+        start_mark = start_mark.encode("utf8")
+        end_mark = end_mark.encode("utf8")
+        unk_mark = unk_mark.encode("utf8")
+        self._src_vocab = self.load_dict(src_vocab_fpath)
+        self._trg_vocab = self.load_dict(trg_vocab_fpath)
+        self._bos_idx = self._src_vocab[start_mark]
+        self._eos_idx = self._src_vocab[end_mark]
+        self._unk_idx = self._src_vocab[unk_mark]
+        self._only_src = only_src
+        self._pool_size = pool_size
+        self._batch_size = batch_size
+        self._device_count = device_count
+        self._n_head = n_head
+        self._use_token_batch = use_token_batch
+        self._sort_type = sort_type
+        self._clip_last_batch = clip_last_batch
+        self._shuffle = shuffle
+        self._shuffle_batch = shuffle_batch
+        self._min_length = min_length
+        self._max_length = max_length
+        self._field_delimiter = field_delimiter
+        self._token_delimiter = token_delimiter
+        self.load_src_trg_ids(fpattern, tar_fname)
+        self._random = np.random
+        self._random.seed(seed)
+
+    def load_src_trg_ids(self, fpattern, tar_fname):
+        converters = [
+            Converter(vocab=self._src_vocab,
+                      beg=self._bos_idx,
+                      end=self._eos_idx,
+                      unk=self._unk_idx,
+                      delimiter=self._token_delimiter,
+                      add_beg=False)
+        ]
+        if not self._only_src:
+            converters.append(
+                Converter(vocab=self._trg_vocab,
+                          beg=self._bos_idx,
+                          end=self._eos_idx,
+                          unk=self._unk_idx,
+                          delimiter=self._token_delimiter,
+                          add_beg=True))
+
+        converters = ComposedConverter(converters)
+
+        self._src_seq_ids = []
+        self._trg_seq_ids = None if self._only_src else []
+        self._sample_infos = []
+
+        for i, line in enumerate(self._load_lines(fpattern, tar_fname)):
+            src_trg_ids = converters(line)
+            self._src_seq_ids.append(src_trg_ids[0])
+            lens = [len(src_trg_ids[0])]
+            if not self._only_src:
+                self._trg_seq_ids.append(src_trg_ids[1])
+                lens.append(len(src_trg_ids[1]))
+            self._sample_infos.append(SampleInfo(i, max(lens), min(lens)))
+
+    def _load_lines(self, fpattern, tar_fname):
+        fpaths = glob.glob(fpattern)
+        assert len(fpaths) > 0, "no matching file to the provided data path"
+
+        if len(fpaths) == 1 and tarfile.is_tarfile(fpaths[0]):
+            if tar_fname is None:
+                raise Exception("If tar file provided, please set tar_fname.")
+
+            f = tarfile.open(fpaths[0], "rb")
+            for line in f.extractfile(tar_fname):
+                fields = line.strip(b"\n").split(self._field_delimiter)
+                if (not self._only_src
+                        and len(fields) == 2) or (self._only_src
+                                                  and len(fields) == 1):
+                    yield fields
+        else:
+            for fpath in fpaths:
+                if not os.path.isfile(fpath):
+                    raise IOError("Invalid file: %s" % fpath)
+
+                with open(fpath, "rb") as f:
+                    for line in f:
+                        fields = line.strip(b"\n").split(self._field_delimiter)
+                        if (not self._only_src
+                                and len(fields) == 2) or (self._only_src
+                                                          and len(fields) == 1):
+                            yield fields
+
+    @staticmethod
+    def load_dict(dict_path, reverse=False):
+        word_dict = {}
+        with open(dict_path, "rb") as fdict:
+            for idx, line in enumerate(fdict):
+                if reverse:
+                    word_dict[idx] = line.strip(b"\n")
+                else:
+                    word_dict[line.strip(b"\n")] = idx
+        return word_dict
+
+    def batch_generator(self, batch_size, use_token_batch):
+        def __impl__():
+            # global sort or global shuffle
+            if self._sort_type == SortType.GLOBAL:
+                infos = sorted(self._sample_infos, key=lambda x: x.max_len)
+            else:
+                if self._shuffle:
+                    infos = self._sample_infos
+                    self._random.shuffle(infos)
+                else:
+                    infos = self._sample_infos
+
+                if self._sort_type == SortType.POOL:
+                    reverse = True
+                    for i in range(0, len(infos), self._pool_size):
+                        # to avoid placing short next to long sentences
+                        reverse = not reverse
+                        infos[i:i + self._pool_size] = sorted(
+                            infos[i:i + self._pool_size],
+                            key=lambda x: x.max_len,
+                            reverse=reverse)
+
+            # concat batch
+            batches = []
+            batch_creator = TokenBatchCreator(
+                batch_size) if use_token_batch else SentenceBatchCreator(
+                    batch_size)
+            batch_creator = MinMaxFilter(self._max_length, self._min_length,
+                                         batch_creator)
+
+            for info in infos:
+                batch = batch_creator.append(info)
+                if batch is not None:
+                    batches.append(batch)
+
+            if not self._clip_last_batch and len(batch_creator.batch) != 0:
+                batches.append(batch_creator.batch)
+
+            if self._shuffle_batch:
+                self._random.shuffle(batches)
+
+            for batch in batches:
+                batch_ids = [info.i for info in batch]
+
+                if self._only_src:
+                    yield [[self._src_seq_ids[idx]] for idx in batch_ids]
+                else:
+                    yield [(self._src_seq_ids[idx], self._trg_seq_ids[idx][:-1],
+                            self._trg_seq_ids[idx][1:]) for idx in batch_ids]
+
+        return __impl__
+
+    @staticmethod
+    def stack(data_reader, count, clip_last=True):
+        def __impl__():
+            res = []
+            for item in data_reader():
+                res.append(item)
+                if len(res) == count:
+                    yield res
+                    res = []
+            if len(res) == count:
+                yield res
+            elif not clip_last:
+                data = []
+                for item in res:
+                    data += item
+                if len(data) > count:
+                    inst_num_per_part = len(data) // count
+                    yield [
+                        data[inst_num_per_part * i:inst_num_per_part * (i + 1)]
+                        for i in range(count)
+                    ]
+
+        return __impl__
+
+    @staticmethod
+    def split(data_reader, count):
+        def __impl__():
+            for item in data_reader():
+                inst_num_per_part = len(item) // count
+                for i in range(count):
+                    yield item[inst_num_per_part * i:inst_num_per_part *
+                               (i + 1)]
+
+        return __impl__
+
+    def data_generator(self, phase, place=None):
+        # Any token included in dict can be used to pad, since the paddings' loss
+        # will be masked out by weights and make no effect on parameter gradients.
+        src_pad_idx = trg_pad_idx = self._eos_idx
+        bos_idx = self._bos_idx
+        n_head = self._n_head
+        data_reader = self.batch_generator(
+            self._batch_size *
+            (1 if self._use_token_batch else self._device_count),
+            self._use_token_batch)
+        if not self._use_token_batch:
+            # to make data on each device have similar token number
+            data_reader = self.split(data_reader, self._device_count)
+
+        def __for_train__():
+            for data in data_reader():
+                data_inputs = prepare_train_input(data, src_pad_idx,
+                                                  trg_pad_idx, n_head)
+                yield data_inputs
+
+        def __for_predict__():
+            for data in data_reader():
+                data_inputs = prepare_infer_input(data, src_pad_idx, bos_idx,
+                                                  n_head, place)
+                yield data_inputs
+
+        return __for_train__ if phase == "train" else __for_predict__
+
+    def get_vocab_summary(self):
+        return len(self._src_vocab), len(
+            self._trg_vocab), self._bos_idx, self._eos_idx, self._unk_idx
diff --git a/transformer/train.py b/transformer/train.py
new file mode 100644
index 0000000000000000000000000000000000000000..6cda90e915875fdc820854c9bd0022f0250ed579
--- /dev/null
+++ b/transformer/train.py
@@ -0,0 +1,206 @@
+# Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+import os
+import six
+import sys
+sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+import time
+import contextlib
+
+import numpy as np
+import paddle
+import paddle.fluid as fluid
+from paddle.fluid.dygraph import to_variable
+
+from utils.configure import PDConfig
+from utils.check import check_gpu, check_version
+
+# include task-specific libs
+import reader
+from transformer import Transformer, CrossEntropyCriterion, NoamDecay
+
+
+def do_train(args):
+    device_ids = list(range(args.num_devices))
+
+    @contextlib.contextmanager
+    def null_guard():
+        yield
+
+    guard = fluid.dygraph.guard() if args.eager_run else null_guard()
+
+    # define the data generator
+    processor = reader.DataProcessor(fpattern=args.training_file,
+                                     src_vocab_fpath=args.src_vocab_fpath,
+                                     trg_vocab_fpath=args.trg_vocab_fpath,
+                                     token_delimiter=args.token_delimiter,
+                                     use_token_batch=args.use_token_batch,
+                                     batch_size=args.batch_size,
+                                     device_count=args.num_devices,
+                                     pool_size=args.pool_size,
+                                     sort_type=args.sort_type,
+                                     shuffle=args.shuffle,
+                                     shuffle_batch=args.shuffle_batch,
+                                     start_mark=args.special_token[0],
+                                     end_mark=args.special_token[1],
+                                     unk_mark=args.special_token[2],
+                                     max_length=args.max_length,
+                                     n_head=args.n_head)
+    batch_generator = processor.data_generator(phase="train")
+    if args.validation_file:
+        val_processor = reader.DataProcessor(
+            fpattern=args.validation_file,
+            src_vocab_fpath=args.src_vocab_fpath,
+            trg_vocab_fpath=args.trg_vocab_fpath,
+            token_delimiter=args.token_delimiter,
+            use_token_batch=args.use_token_batch,
+            batch_size=args.batch_size,
+            device_count=args.num_devices,
+            pool_size=args.pool_size,
+            sort_type=args.sort_type,
+            shuffle=False,
+            shuffle_batch=False,
+            start_mark=args.special_token[0],
+            end_mark=args.special_token[1],
+            unk_mark=args.special_token[2],
+            max_length=args.max_length,
+            n_head=args.n_head)
+        val_batch_generator = val_processor.data_generator(phase="train")
+    args.src_vocab_size, args.trg_vocab_size, args.bos_idx, args.eos_idx, \
+        args.unk_idx = processor.get_vocab_summary()
+
+
+    with guard:
+        # set seed for CE
+        random_seed = eval(str(args.random_seed))
+        if random_seed is not None:
+            fluid.default_main_program().random_seed = random_seed
+            fluid.default_startup_program().random_seed = random_seed
+
+        # define data loader
+        train_loader = batch_generator
+        if args.validation_file:
+            val_loader = val_batch_generator
+
+        # define model
+        transformer = Transformer(
+            args.src_vocab_size, args.trg_vocab_size, args.max_length + 1,
+            args.n_layer, args.n_head, args.d_key, args.d_value, args.d_model,
+            args.d_inner_hid, args.prepostprocess_dropout,
+            args.attention_dropout, args.relu_dropout, args.preprocess_cmd,
+            args.postprocess_cmd, args.weight_sharing, args.bos_idx,
+            args.eos_idx)
+
+        transformer.prepare(
+            fluid.optimizer.Adam(
+                learning_rate=fluid.layers.noam_decay(
+                    args.d_model, args.warmup_steps),  # args.learning_rate),
+                beta1=args.beta1,
+                beta2=args.beta2,
+                epsilon=float(args.eps),
+                parameter_list=transformer.parameters()),
+            CrossEntropyCriterion(args.label_smooth_eps))
+
+        ## init from some checkpoint, to resume the previous training
+        if args.init_from_checkpoint:
+            transformer.load(
+                os.path.join(args.init_from_checkpoint, "transformer"))
+        ## init from some pretrain models, to better solve the current task
+        if args.init_from_pretrain_model:
+            transformer.load(
+                os.path.join(args.init_from_pretrain_model, "transformer"))
+
+        # the best cross-entropy value with label smoothing
+        loss_normalizer = -(
+            (1. - args.label_smooth_eps) * np.log(
+                (1. - args.label_smooth_eps)) +
+            args.label_smooth_eps * np.log(args.label_smooth_eps /
+                                           (args.trg_vocab_size - 1) + 1e-20))
+
+        step_idx = 0
+        # train loop
+        for pass_id in range(args.epoch):
+            pass_start_time = time.time()
+            batch_id = 0
+            for input_data in train_loader():
+                outputs, losses = transformer.train(input_data[:-2],
+                                                    input_data[-2:],
+                                                    device='gpu',
+                                                    device_ids=device_ids)
+
+                if step_idx % args.print_step == 0:
+                    total_avg_cost = np.sum(losses)
+
+                    if step_idx == 0:
+                        logging.info(
+                            "step_idx: %d, epoch: %d, batch: %d, avg loss: %f, "
+                            "normalized loss: %f, ppl: %f" %
+                            (step_idx, pass_id, batch_id, total_avg_cost,
+                            total_avg_cost - loss_normalizer,
+                            np.exp([min(total_avg_cost, 100)])))
+                        avg_batch_time = time.time()
+                    else:
+                        logging.info(
+                            "step_idx: %d, epoch: %d, batch: %d, avg loss: %f, "
+                            "normalized loss: %f, ppl: %f, speed: %.2f step/s" %
+                            (step_idx, pass_id, batch_id, total_avg_cost,
+                            total_avg_cost - loss_normalizer,
+                            np.exp([min(total_avg_cost, 100)]),
+                            args.print_step / (time.time() - avg_batch_time)))
+                        avg_batch_time = time.time()
+
+
+                if step_idx % args.save_step == 0 and step_idx != 0:
+                    # validation: how to accumulate with Model loss
+                    if args.validation_file:
+                        total_avg_cost = 0
+                        for idx, input_data in enumerate(val_loader()):
+                            outputs, losses = transformer.eval(
+                                input_data[:-2],
+                                input_data[-2:],
+                                device='gpu',
+                                device_ids=device_ids)
+                            total_avg_cost += np.sum(losses)
+                        total_avg_cost /= idx + 1
+                        logging.info("validation, step_idx: %d, avg loss: %f, "
+                                     "normalized loss: %f, ppl: %f" %
+                                     (step_idx, total_avg_cost,
+                                      total_avg_cost - loss_normalizer,
+                                      np.exp([min(total_avg_cost, 100)])))
+
+                        transformer.save(
+                            os.path.join(args.save_model,
+                                         "step_" + str(step_idx),
+                                         "transformer"))
+
+                batch_id += 1
+                step_idx += 1
+
+        time_consumed = time.time() - pass_start_time
+
+        if args.save_model:
+            transformer.save(
+                os.path.join(args.save_model, "step_final", "transformer"))
+
+
+if __name__ == "__main__":
+    args = PDConfig(yaml_file="./transformer.yaml")
+    args.build()
+    args.Print()
+    check_gpu(args.use_cuda)
+    check_version()
+
+    do_train(args)
diff --git a/transformer/transformer.py b/transformer/transformer.py
new file mode 100644
index 0000000000000000000000000000000000000000..e1011a55db16baa877b38044db3185a1b9def4e0
--- /dev/null
+++ b/transformer/transformer.py
@@ -0,0 +1,1102 @@
+# Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import print_function
+
+import numpy as np
+
+import paddle.fluid as fluid
+import paddle.fluid.layers as layers
+from paddle.fluid.dygraph import Embedding, LayerNorm, Linear, Layer, to_variable
+from paddle.fluid.dygraph.learning_rate_scheduler import LearningRateDecay
+from model import Model, shape_hints, CrossEntropy, Loss
+
+
+def position_encoding_init(n_position, d_pos_vec):
+    """
+    Generate the initial values for the sinusoid position encoding table.
+    """
+    channels = d_pos_vec
+    position = np.arange(n_position)
+    num_timescales = channels // 2
+    log_timescale_increment = (np.log(float(1e4) / float(1)) /
+                               (num_timescales - 1))
+    inv_timescales = np.exp(
+        np.arange(num_timescales)) * -log_timescale_increment
+    scaled_time = np.expand_dims(position, 1) * np.expand_dims(
+        inv_timescales, 0)
+    signal = np.concatenate([np.sin(scaled_time), np.cos(scaled_time)], axis=1)
+    signal = np.pad(signal, [[0, 0], [0, np.mod(channels, 2)]], 'constant')
+    position_enc = signal
+    return position_enc.astype("float32")
+
+
+class NoamDecay(LearningRateDecay):
+    """
+    learning rate scheduler
+    """
+    def __init__(self,
+                 d_model,
+                 warmup_steps,
+                 static_lr=2.0,
+                 begin=1,
+                 step=1,
+                 dtype='float32'):
+        super(NoamDecay, self).__init__(begin, step, dtype)
+        self.d_model = d_model
+        self.warmup_steps = warmup_steps
+        self.static_lr = static_lr
+
+    def step(self):
+        a = self.create_lr_var(self.step_num**-0.5)
+        b = self.create_lr_var((self.warmup_steps**-1.5) * self.step_num)
+        lr_value = (self.d_model**-0.5) * layers.elementwise_min(
+            a, b) * self.static_lr
+        return lr_value
+
+
+class PrePostProcessLayer(Layer):
+    """
+    PrePostProcessLayer
+    """
+    def __init__(self, process_cmd, d_model, dropout_rate):
+        super(PrePostProcessLayer, self).__init__()
+        self.process_cmd = process_cmd
+        self.functors = []
+        for cmd in self.process_cmd:
+            if cmd == "a":  # add residual connection
+                self.functors.append(lambda x, y: x + y if y else x)
+            elif cmd == "n":  # add layer normalization
+                self.functors.append(
+                    self.add_sublayer(
+                        "layer_norm_%d" %
+                        len(self.sublayers(include_sublayers=False)),
+                        LayerNorm(
+                            normalized_shape=d_model,
+                            param_attr=fluid.ParamAttr(
+                                initializer=fluid.initializer.Constant(1.)),
+                            bias_attr=fluid.ParamAttr(
+                                initializer=fluid.initializer.Constant(0.)))))
+            elif cmd == "d":  # add dropout
+                self.functors.append(lambda x: layers.dropout(
+                    x, dropout_prob=dropout_rate, is_test=False)
+                                     if dropout_rate else x)
+
+    def forward(self, x, residual=None):
+        for i, cmd in enumerate(self.process_cmd):
+            if cmd == "a":
+                x = self.functors[i](x, residual)
+            else:
+                x = self.functors[i](x)
+        return x
+
+
+class MultiHeadAttention(Layer):
+    """
+    Multi-Head Attention
+    """
+    def __init__(self, d_key, d_value, d_model, n_head=1, dropout_rate=0.):
+        super(MultiHeadAttention, self).__init__()
+        self.n_head = n_head
+        self.d_key = d_key
+        self.d_value = d_value
+        self.d_model = d_model
+        self.dropout_rate = dropout_rate
+        self.q_fc = Linear(input_dim=d_model,
+                           output_dim=d_key * n_head,
+                           bias_attr=False)
+        self.k_fc = Linear(input_dim=d_model,
+                           output_dim=d_key * n_head,
+                           bias_attr=False)
+        self.v_fc = Linear(input_dim=d_model,
+                           output_dim=d_value * n_head,
+                           bias_attr=False)
+        self.proj_fc = Linear(input_dim=d_value * n_head,
+                              output_dim=d_model,
+                              bias_attr=False)
+
+    def _prepare_qkv(self, queries, keys, values, cache=None):
+        if keys is None:  # self-attention
+            keys, values = queries, queries
+            static_kv = False
+        else:  # cross-attention
+            static_kv = True
+
+        q = self.q_fc(queries)
+        q = layers.reshape(x=q, shape=[0, 0, self.n_head, self.d_key])
+        q = layers.transpose(x=q, perm=[0, 2, 1, 3])
+
+        if cache is not None and static_kv and "static_k" in cache:
+            # for encoder-decoder attention in inference and has cached
+            k = cache["static_k"]
+            v = cache["static_v"]
+        else:
+            k = self.k_fc(keys)
+            v = self.v_fc(values)
+            k = layers.reshape(x=k, shape=[0, 0, self.n_head, self.d_key])
+            k = layers.transpose(x=k, perm=[0, 2, 1, 3])
+            v = layers.reshape(x=v, shape=[0, 0, self.n_head, self.d_value])
+            v = layers.transpose(x=v, perm=[0, 2, 1, 3])
+
+        if cache is not None:
+            if static_kv and not "static_k" in cache:
+                # for encoder-decoder attention in inference and has not cached
+                cache["static_k"], cache["static_v"] = k, v
+            elif not static_kv:
+                # for decoder self-attention in inference
+                cache_k, cache_v = cache["k"], cache["v"]
+                k = layers.concat([cache_k, k], axis=2)
+                v = layers.concat([cache_v, v], axis=2)
+                cache["k"], cache["v"] = k, v
+
+        return q, k, v
+
+    def forward(self, queries, keys, values, attn_bias, cache=None):
+        # compute q ,k ,v
+        q, k, v = self._prepare_qkv(queries, keys, values, cache)
+
+        # scale dot product attention
+        product = layers.matmul(x=q,
+                                y=k,
+                                transpose_y=True,
+                                alpha=self.d_model**-0.5)
+        if attn_bias:
+            product += attn_bias
+        weights = layers.softmax(product)
+        if self.dropout_rate:
+            weights = layers.dropout(weights,
+                                     dropout_prob=self.dropout_rate,
+                                     is_test=False)
+
+        out = layers.matmul(weights, v)
+
+        # combine heads
+        out = layers.transpose(out, perm=[0, 2, 1, 3])
+        out = layers.reshape(x=out, shape=[0, 0, out.shape[2] * out.shape[3]])
+
+        # project to output
+        out = self.proj_fc(out)
+        return out
+
+
+class FFN(Layer):
+    """
+    Feed-Forward Network
+    """
+    def __init__(self, d_inner_hid, d_model, dropout_rate):
+        super(FFN, self).__init__()
+        self.dropout_rate = dropout_rate
+        self.fc1 = Linear(input_dim=d_model, output_dim=d_inner_hid, act="relu")
+        self.fc2 = Linear(input_dim=d_inner_hid, output_dim=d_model)
+
+    def forward(self, x):
+        hidden = self.fc1(x)
+        if self.dropout_rate:
+            hidden = layers.dropout(hidden,
+                                    dropout_prob=self.dropout_rate,
+                                    is_test=False)
+        out = self.fc2(hidden)
+        return out
+
+
+class EncoderLayer(Layer):
+    """
+    EncoderLayer
+    """
+    def __init__(self,
+                 n_head,
+                 d_key,
+                 d_value,
+                 d_model,
+                 d_inner_hid,
+                 prepostprocess_dropout,
+                 attention_dropout,
+                 relu_dropout,
+                 preprocess_cmd="n",
+                 postprocess_cmd="da"):
+
+        super(EncoderLayer, self).__init__()
+
+        self.preprocesser1 = PrePostProcessLayer(preprocess_cmd, d_model,
+                                                 prepostprocess_dropout)
+        self.self_attn = MultiHeadAttention(d_key, d_value, d_model, n_head,
+                                            attention_dropout)
+        self.postprocesser1 = PrePostProcessLayer(postprocess_cmd, d_model,
+                                                  prepostprocess_dropout)
+
+        self.preprocesser2 = PrePostProcessLayer(preprocess_cmd, d_model,
+                                                 prepostprocess_dropout)
+        self.ffn = FFN(d_inner_hid, d_model, relu_dropout)
+        self.postprocesser2 = PrePostProcessLayer(postprocess_cmd, d_model,
+                                                  prepostprocess_dropout)
+
+    def forward(self, enc_input, attn_bias):
+        attn_output = self.self_attn(self.preprocesser1(enc_input), None, None,
+                                     attn_bias)
+        attn_output = self.postprocesser1(attn_output, enc_input)
+
+        ffn_output = self.ffn(self.preprocesser2(attn_output))
+        ffn_output = self.postprocesser2(ffn_output, attn_output)
+        return ffn_output
+
+
+class Encoder(Layer):
+    """
+    encoder
+    """
+    def __init__(self,
+                 n_layer,
+                 n_head,
+                 d_key,
+                 d_value,
+                 d_model,
+                 d_inner_hid,
+                 prepostprocess_dropout,
+                 attention_dropout,
+                 relu_dropout,
+                 preprocess_cmd="n",
+                 postprocess_cmd="da"):
+
+        super(Encoder, self).__init__()
+
+        self.encoder_layers = list()
+        for i in range(n_layer):
+            self.encoder_layers.append(
+                self.add_sublayer(
+                    "layer_%d" % i,
+                    EncoderLayer(n_head, d_key, d_value, d_model, d_inner_hid,
+                                 prepostprocess_dropout, attention_dropout,
+                                 relu_dropout, preprocess_cmd,
+                                 postprocess_cmd)))
+        self.processer = PrePostProcessLayer(preprocess_cmd, d_model,
+                                             prepostprocess_dropout)
+
+    def forward(self, enc_input, attn_bias):
+        for encoder_layer in self.encoder_layers:
+            enc_output = encoder_layer(enc_input, attn_bias)
+            enc_input = enc_output
+
+        return self.processer(enc_output)
+
+
+class Embedder(Layer):
+    """
+    Word Embedding + Position Encoding
+    """
+    def __init__(self, vocab_size, emb_dim, bos_idx=0):
+        super(Embedder, self).__init__()
+
+        self.word_embedder = Embedding(
+            size=[vocab_size, emb_dim],
+            padding_idx=bos_idx,
+            param_attr=fluid.ParamAttr(
+                initializer=fluid.initializer.Normal(0., emb_dim**-0.5)))
+
+    def forward(self, word):
+        word_emb = self.word_embedder(word)
+        return word_emb
+
+
+class WrapEncoder(Layer):
+    """
+    embedder + encoder
+    """
+    def __init__(self, src_vocab_size, max_length, n_layer, n_head, d_key,
+                 d_value, d_model, d_inner_hid, prepostprocess_dropout,
+                 attention_dropout, relu_dropout, preprocess_cmd,
+                 postprocess_cmd, word_embedder):
+        super(WrapEncoder, self).__init__()
+
+        self.emb_dropout = prepostprocess_dropout
+        self.emb_dim = d_model
+        self.word_embedder = word_embedder
+        self.pos_encoder = Embedding(
+            size=[max_length, self.emb_dim],
+            param_attr=fluid.ParamAttr(
+                initializer=fluid.initializer.NumpyArrayInitializer(
+                    position_encoding_init(max_length, self.emb_dim)),
+                trainable=False))
+
+        self.encoder = Encoder(n_layer, n_head, d_key, d_value, d_model,
+                               d_inner_hid, prepostprocess_dropout,
+                               attention_dropout, relu_dropout, preprocess_cmd,
+                               postprocess_cmd)
+
+    def forward(self, src_word, src_pos, src_slf_attn_bias):
+        word_emb = self.word_embedder(src_word)
+        word_emb = layers.scale(x=word_emb, scale=self.emb_dim**0.5)
+        pos_enc = self.pos_encoder(src_pos)
+        pos_enc.stop_gradient = True
+        emb = word_emb + pos_enc
+        enc_input = layers.dropout(emb,
+                                   dropout_prob=self.emb_dropout,
+                                   is_test=False) if self.emb_dropout else emb
+
+        enc_output = self.encoder(enc_input, src_slf_attn_bias)
+        return enc_output
+
+
+class DecoderLayer(Layer):
+    """
+    decoder
+    """
+    def __init__(self,
+                 n_head,
+                 d_key,
+                 d_value,
+                 d_model,
+                 d_inner_hid,
+                 prepostprocess_dropout,
+                 attention_dropout,
+                 relu_dropout,
+                 preprocess_cmd="n",
+                 postprocess_cmd="da"):
+        super(DecoderLayer, self).__init__()
+
+        self.preprocesser1 = PrePostProcessLayer(preprocess_cmd, d_model,
+                                                 prepostprocess_dropout)
+        self.self_attn = MultiHeadAttention(d_key, d_value, d_model, n_head,
+                                            attention_dropout)
+        self.postprocesser1 = PrePostProcessLayer(postprocess_cmd, d_model,
+                                                  prepostprocess_dropout)
+
+        self.preprocesser2 = PrePostProcessLayer(preprocess_cmd, d_model,
+                                                 prepostprocess_dropout)
+        self.cross_attn = MultiHeadAttention(d_key, d_value, d_model, n_head,
+                                             attention_dropout)
+        self.postprocesser2 = PrePostProcessLayer(postprocess_cmd, d_model,
+                                                  prepostprocess_dropout)
+
+        self.preprocesser3 = PrePostProcessLayer(preprocess_cmd, d_model,
+                                                 prepostprocess_dropout)
+        self.ffn = FFN(d_inner_hid, d_model, relu_dropout)
+        self.postprocesser3 = PrePostProcessLayer(postprocess_cmd, d_model,
+                                                  prepostprocess_dropout)
+
+    def forward(self,
+                dec_input,
+                enc_output,
+                self_attn_bias,
+                cross_attn_bias,
+                cache=None):
+        self_attn_output = self.self_attn(self.preprocesser1(dec_input), None,
+                                          None, self_attn_bias, cache)
+        self_attn_output = self.postprocesser1(self_attn_output, dec_input)
+
+        cross_attn_output = self.cross_attn(
+            self.preprocesser2(self_attn_output), enc_output, enc_output,
+            cross_attn_bias, cache)
+        cross_attn_output = self.postprocesser2(cross_attn_output,
+                                                self_attn_output)
+
+        ffn_output = self.ffn(self.preprocesser3(cross_attn_output))
+        ffn_output = self.postprocesser3(ffn_output, cross_attn_output)
+
+        return ffn_output
+
+
+class Decoder(Layer):
+    """
+    decoder
+    """
+    def __init__(self, n_layer, n_head, d_key, d_value, d_model, d_inner_hid,
+                 prepostprocess_dropout, attention_dropout, relu_dropout,
+                 preprocess_cmd, postprocess_cmd):
+        super(Decoder, self).__init__()
+
+        self.decoder_layers = list()
+        for i in range(n_layer):
+            self.decoder_layers.append(
+                self.add_sublayer(
+                    "layer_%d" % i,
+                    DecoderLayer(n_head, d_key, d_value, d_model, d_inner_hid,
+                                 prepostprocess_dropout, attention_dropout,
+                                 relu_dropout, preprocess_cmd,
+                                 postprocess_cmd)))
+        self.processer = PrePostProcessLayer(preprocess_cmd, d_model,
+                                             prepostprocess_dropout)
+
+    def forward(self,
+                dec_input,
+                enc_output,
+                self_attn_bias,
+                cross_attn_bias,
+                caches=None):
+        for i, decoder_layer in enumerate(self.decoder_layers):
+            dec_output = decoder_layer(dec_input, enc_output, self_attn_bias,
+                                       cross_attn_bias,
+                                       None if caches is None else caches[i])
+            dec_input = dec_output
+
+        return self.processer(dec_output)
+
+
+class WrapDecoder(Layer):
+    """
+    embedder + decoder
+    """
+    def __init__(self, trg_vocab_size, max_length, n_layer, n_head, d_key,
+                 d_value, d_model, d_inner_hid, prepostprocess_dropout,
+                 attention_dropout, relu_dropout, preprocess_cmd,
+                 postprocess_cmd, share_input_output_embed, word_embedder):
+        super(WrapDecoder, self).__init__()
+
+        self.emb_dropout = prepostprocess_dropout
+        self.emb_dim = d_model
+        self.word_embedder = word_embedder
+        self.pos_encoder = Embedding(
+            size=[max_length, self.emb_dim],
+            param_attr=fluid.ParamAttr(
+                initializer=fluid.initializer.NumpyArrayInitializer(
+                    position_encoding_init(max_length, self.emb_dim)),
+                trainable=False))
+
+        self.decoder = Decoder(n_layer, n_head, d_key, d_value, d_model,
+                               d_inner_hid, prepostprocess_dropout,
+                               attention_dropout, relu_dropout, preprocess_cmd,
+                               postprocess_cmd)
+
+        if share_input_output_embed:
+            self.linear = lambda x: layers.matmul(x=x,
+                                                  y=self.word_embedder.
+                                                  word_embedder.weight,
+                                                  transpose_y=True)
+        else:
+            self.linear = Linear(input_dim=d_model,
+                                 output_dim=trg_vocab_size,
+                                 bias_attr=False)
+
+    def forward(self,
+                trg_word,
+                trg_pos,
+                trg_slf_attn_bias,
+                trg_src_attn_bias,
+                enc_output,
+                caches=None):
+        word_emb = self.word_embedder(trg_word)
+        word_emb = layers.scale(x=word_emb, scale=self.emb_dim**0.5)
+        pos_enc = self.pos_encoder(trg_pos)
+        pos_enc.stop_gradient = True
+        emb = word_emb + pos_enc
+        dec_input = layers.dropout(emb,
+                                   dropout_prob=self.emb_dropout,
+                                   is_test=False) if self.emb_dropout else emb
+        dec_output = self.decoder(dec_input, enc_output, trg_slf_attn_bias,
+                                  trg_src_attn_bias, caches)
+        dec_output = layers.reshape(
+            dec_output,
+            shape=[-1, dec_output.shape[-1]],
+        )
+        logits = self.linear(dec_output)
+        return logits
+
+
+# class CrossEntropyCriterion(object):
+#     def __init__(self, label_smooth_eps):
+#         self.label_smooth_eps = label_smooth_eps
+
+#     def __call__(self, predict, label, weights):
+#         if self.label_smooth_eps:
+#             label_out = layers.label_smooth(label=layers.one_hot(
+#                 input=label, depth=predict.shape[-1]),
+#                                             epsilon=self.label_smooth_eps)
+
+#         cost = layers.softmax_with_cross_entropy(
+#             logits=predict,
+#             label=label_out,
+#             soft_label=True if self.label_smooth_eps else False)
+#         weighted_cost = cost * weights
+#         sum_cost = layers.reduce_sum(weighted_cost)
+#         token_num = layers.reduce_sum(weights)
+#         token_num.stop_gradient = True
+#         avg_cost = sum_cost / token_num
+#         return sum_cost, avg_cost, token_num
+
+
+class CrossEntropyCriterion(Loss):
+    def __init__(self, label_smooth_eps):
+        super(CrossEntropyCriterion, self).__init__()
+        self.label_smooth_eps = label_smooth_eps
+
+    def forward(self, outputs, labels):
+        predict = outputs[0]
+        label, weights = labels
+        if self.label_smooth_eps:
+            label = layers.label_smooth(label=layers.one_hot(
+                input=label, depth=predict.shape[-1]),
+                                            epsilon=self.label_smooth_eps)
+
+        cost = layers.softmax_with_cross_entropy(
+            logits=predict,
+            label=label,
+            soft_label=True if self.label_smooth_eps else False)
+        weighted_cost = cost * weights
+        sum_cost = layers.reduce_sum(weighted_cost)
+        token_num = layers.reduce_sum(weights)
+        token_num.stop_gradient = True
+        avg_cost = sum_cost / token_num
+        return avg_cost
+
+    def infer_shape(self, _):
+        return [[None, 1], [None, 1]]
+
+    def infer_dtype(self, _):
+        return ["int64", "float32"]
+
+
+class Transformer(Model):
+    """
+    model
+    """
+    def __init__(self,
+                 src_vocab_size,
+                 trg_vocab_size,
+                 max_length,
+                 n_layer,
+                 n_head,
+                 d_key,
+                 d_value,
+                 d_model,
+                 d_inner_hid,
+                 prepostprocess_dropout,
+                 attention_dropout,
+                 relu_dropout,
+                 preprocess_cmd,
+                 postprocess_cmd,
+                 weight_sharing,
+                 bos_id=0,
+                 eos_id=1):
+        super(Transformer, self).__init__()
+        src_word_embedder = Embedder(vocab_size=src_vocab_size,
+                                     emb_dim=d_model,
+                                     bos_idx=bos_id)
+        self.encoder = WrapEncoder(src_vocab_size, max_length, n_layer, n_head,
+                                   d_key, d_value, d_model, d_inner_hid,
+                                   prepostprocess_dropout, attention_dropout,
+                                   relu_dropout, preprocess_cmd,
+                                   postprocess_cmd, src_word_embedder)
+        if weight_sharing:
+            assert src_vocab_size == trg_vocab_size, (
+                "Vocabularies in source and target should be same for weight sharing."
+            )
+            trg_word_embedder = src_word_embedder
+        else:
+            trg_word_embedder = Embedder(vocab_size=trg_vocab_size,
+                                         emb_dim=d_model,
+                                         bos_idx=bos_id)
+        self.decoder = WrapDecoder(trg_vocab_size, max_length, n_layer, n_head,
+                                   d_key, d_value, d_model, d_inner_hid,
+                                   prepostprocess_dropout, attention_dropout,
+                                   relu_dropout, preprocess_cmd,
+                                   postprocess_cmd, weight_sharing,
+                                   trg_word_embedder)
+
+        self.trg_vocab_size = trg_vocab_size
+        self.n_layer = n_layer
+        self.n_head = n_head
+        self.d_key = d_key
+        self.d_value = d_value
+
+    @shape_hints(src_word=[None, None],
+                 src_pos=[None, None],
+                 src_slf_attn_bias=[None, 8, None, None],
+                 trg_word=[None, None],
+                 trg_pos=[None, None],
+                 trg_slf_attn_bias=[None, 8, None, None],
+                 trg_src_attn_bias=[None, 8, None, None])
+    def forward(self, src_word, src_pos, src_slf_attn_bias, trg_word, trg_pos,
+                trg_slf_attn_bias, trg_src_attn_bias):
+        enc_output = self.encoder(src_word, src_pos, src_slf_attn_bias)
+        predict = self.decoder(trg_word, trg_pos, trg_slf_attn_bias,
+                               trg_src_attn_bias, enc_output)
+        return predict
+
+    def beam_search_v2(self,
+                       src_word,
+                       src_pos,
+                       src_slf_attn_bias,
+                       trg_word,
+                       trg_src_attn_bias,
+                       bos_id=0,
+                       eos_id=1,
+                       beam_size=4,
+                       max_len=None,
+                       alpha=0.6):
+        """
+        Beam search with the alive and finished two queues, both have a beam size
+        capicity separately. It includes `grow_topk` `grow_alive` `grow_finish` as
+        steps.
+
+        1. `grow_topk` selects the top `2*beam_size` candidates to avoid all getting
+        EOS.
+
+        2. `grow_alive` selects the top `beam_size` non-EOS candidates as the inputs
+        of next decoding step.
+
+        3. `grow_finish` compares the already finished candidates in the finished queue
+        and newly added finished candidates from `grow_topk`, and selects the top
+        `beam_size` finished candidates.
+        """
+        def expand_to_beam_size(tensor, beam_size):
+            tensor = layers.reshape(tensor,
+                                    [tensor.shape[0], 1] + tensor.shape[1:])
+            tile_dims = [1] * len(tensor.shape)
+            tile_dims[1] = beam_size
+            return layers.expand(tensor, tile_dims)
+
+        def merge_beam_dim(tensor):
+            return layers.reshape(tensor, [-1] + tensor.shape[2:])
+
+        # run encoder
+        enc_output = self.encoder(src_word, src_pos, src_slf_attn_bias)
+
+        # constant number
+        inf = float(1. * 1e7)
+        batch_size = enc_output.shape[0]
+        max_len = (enc_output.shape[1] + 20) if max_len is None else max_len
+
+        ### initialize states of beam search ###
+        ## init for the alive ##
+        initial_log_probs = to_variable(
+            np.array([[0.] + [-inf] * (beam_size - 1)], dtype="float32"))
+        alive_log_probs = layers.expand(initial_log_probs, [batch_size, 1])
+        alive_seq = to_variable(
+            np.tile(np.array([[[bos_id]]], dtype="int64"),
+                    (batch_size, beam_size, 1)))
+
+        ## init for the finished ##
+        finished_scores = to_variable(
+            np.array([[-inf] * beam_size], dtype="float32"))
+        finished_scores = layers.expand(finished_scores, [batch_size, 1])
+        finished_seq = to_variable(
+            np.tile(np.array([[[bos_id]]], dtype="int64"),
+                    (batch_size, beam_size, 1)))
+        finished_flags = layers.zeros_like(finished_scores)
+
+        ### initialize inputs and states of transformer decoder ###
+        ## init inputs for decoder, shaped `[batch_size*beam_size, ...]`
+        trg_word = layers.reshape(alive_seq[:, :, -1],
+                                  [batch_size * beam_size, 1])
+        trg_src_attn_bias = merge_beam_dim(
+            expand_to_beam_size(trg_src_attn_bias, beam_size))
+        enc_output = merge_beam_dim(expand_to_beam_size(enc_output, beam_size))
+        ## init states (caches) for transformer, need to be updated according to selected beam
+        caches = [{
+            "k":
+            layers.fill_constant(
+                shape=[batch_size * beam_size, self.n_head, 0, self.d_key],
+                dtype=enc_output.dtype,
+                value=0),
+            "v":
+            layers.fill_constant(
+                shape=[batch_size * beam_size, self.n_head, 0, self.d_value],
+                dtype=enc_output.dtype,
+                value=0),
+        } for i in range(self.n_layer)]
+
+        def update_states(caches, beam_idx, beam_size):
+            for cache in caches:
+                cache["k"] = gather_2d_by_gather(cache["k"], beam_idx,
+                                                 beam_size, batch_size, False)
+                cache["v"] = gather_2d_by_gather(cache["v"], beam_idx,
+                                                 beam_size, batch_size, False)
+            return caches
+
+        def gather_2d_by_gather(tensor_nd,
+                                beam_idx,
+                                beam_size,
+                                batch_size,
+                                need_flat=True):
+            batch_idx = layers.range(0, batch_size, 1,
+                                     dtype="int64") * beam_size
+            flat_tensor = merge_beam_dim(tensor_nd) if need_flat else tensor_nd
+            idx = layers.reshape(layers.elementwise_add(beam_idx, batch_idx, 0),
+                                 [-1])
+            new_flat_tensor = layers.gather(flat_tensor, idx)
+            new_tensor_nd = layers.reshape(
+                new_flat_tensor,
+                shape=[batch_size, beam_idx.shape[1]] +
+                tensor_nd.shape[2:]) if need_flat else new_flat_tensor
+            return new_tensor_nd
+
+        def early_finish(alive_log_probs, finished_scores,
+                         finished_in_finished):
+            max_length_penalty = np.power(((5. + max_len) / 6.), alpha)
+            # The best possible score of the most likely alive sequence
+            lower_bound_alive_scores = alive_log_probs[:, 0] / max_length_penalty
+
+            # Now to compute the lowest score of a finished sequence in finished
+            # If the sequence isn't finished, we multiply it's score by 0. since
+            # scores are all -ve, taking the min will give us the score of the lowest
+            # finished item.
+            lowest_score_of_fininshed_in_finished = layers.reduce_min(
+                finished_scores * finished_in_finished, 1)
+            # If none of the sequences have finished, then the min will be 0 and
+            # we have to replace it by -ve INF if it is. The score of any seq in alive
+            # will be much higher than -ve INF and the termination condition will not
+            # be met.
+            lowest_score_of_fininshed_in_finished += (
+                1. - layers.reduce_max(finished_in_finished, 1)) * -inf
+            bound_is_met = layers.reduce_all(
+                layers.greater_than(lowest_score_of_fininshed_in_finished,
+                                    lower_bound_alive_scores))
+
+            return bound_is_met
+
+        def grow_topk(i, logits, alive_seq, alive_log_probs, states):
+            logits = layers.reshape(logits, [batch_size, beam_size, -1])
+            candidate_log_probs = layers.log(layers.softmax(logits, axis=2))
+            log_probs = layers.elementwise_add(candidate_log_probs,
+                                               alive_log_probs, 0)
+
+            length_penalty = np.power(5.0 + (i + 1.0) / 6.0, alpha)
+            curr_scores = log_probs / length_penalty
+            flat_curr_scores = layers.reshape(curr_scores, [batch_size, -1])
+
+            topk_scores, topk_ids = layers.topk(flat_curr_scores,
+                                                k=beam_size * 2)
+
+            topk_log_probs = topk_scores * length_penalty
+
+            topk_beam_index = topk_ids // self.trg_vocab_size
+            topk_ids = topk_ids % self.trg_vocab_size
+
+            # use gather as gather_nd, TODO: use gather_nd
+            topk_seq = gather_2d_by_gather(alive_seq, topk_beam_index,
+                                           beam_size, batch_size)
+            topk_seq = layers.concat(
+                [topk_seq,
+                 layers.reshape(topk_ids, topk_ids.shape + [1])],
+                axis=2)
+            states = update_states(states, topk_beam_index, beam_size)
+            eos = layers.fill_constant(shape=topk_ids.shape,
+                                       dtype="int64",
+                                       value=eos_id)
+            topk_finished = layers.cast(layers.equal(topk_ids, eos), "float32")
+
+            #topk_seq: [batch_size, 2*beam_size, i+1]
+            #topk_log_probs, topk_scores, topk_finished: [batch_size, 2*beam_size]
+            return topk_seq, topk_log_probs, topk_scores, topk_finished, states
+
+        def grow_alive(curr_seq, curr_scores, curr_log_probs, curr_finished,
+                       states):
+            curr_scores += curr_finished * -inf
+            _, topk_indexes = layers.topk(curr_scores, k=beam_size)
+            alive_seq = gather_2d_by_gather(curr_seq, topk_indexes,
+                                            beam_size * 2, batch_size)
+            alive_log_probs = gather_2d_by_gather(curr_log_probs, topk_indexes,
+                                                  beam_size * 2, batch_size)
+            states = update_states(states, topk_indexes, beam_size * 2)
+
+            return alive_seq, alive_log_probs, states
+
+        def grow_finished(finished_seq, finished_scores, finished_flags,
+                          curr_seq, curr_scores, curr_finished):
+            # finished scores
+            finished_seq = layers.concat([
+                finished_seq,
+                layers.fill_constant(shape=[batch_size, beam_size, 1],
+                                     dtype="int64",
+                                     value=eos_id)
+            ],
+                                         axis=2)
+            # Set the scores of the unfinished seq in curr_seq to large negative
+            # values
+            curr_scores += (1. - curr_finished) * -inf
+            # concatenating the sequences and scores along beam axis
+            curr_finished_seq = layers.concat([finished_seq, curr_seq], axis=1)
+            curr_finished_scores = layers.concat([finished_scores, curr_scores],
+                                                 axis=1)
+            curr_finished_flags = layers.concat([finished_flags, curr_finished],
+                                                axis=1)
+            _, topk_indexes = layers.topk(curr_finished_scores, k=beam_size)
+            finished_seq = gather_2d_by_gather(curr_finished_seq, topk_indexes,
+                                               beam_size * 3, batch_size)
+            finished_scores = gather_2d_by_gather(curr_finished_scores,
+                                                  topk_indexes, beam_size * 3,
+                                                  batch_size)
+            finished_flags = gather_2d_by_gather(curr_finished_flags,
+                                                 topk_indexes, beam_size * 3,
+                                                 batch_size)
+            return finished_seq, finished_scores, finished_flags
+
+        for i in range(max_len):
+            trg_pos = layers.fill_constant(shape=trg_word.shape,
+                                           dtype="int64",
+                                           value=i)
+            logits = self.decoder(trg_word, trg_pos, None, trg_src_attn_bias,
+                                  enc_output, caches)
+            topk_seq, topk_log_probs, topk_scores, topk_finished, states = grow_topk(
+                i, logits, alive_seq, alive_log_probs, caches)
+            alive_seq, alive_log_probs, states = grow_alive(
+                topk_seq, topk_scores, topk_log_probs, topk_finished, states)
+            finished_seq, finished_scores, finished_flags = grow_finished(
+                finished_seq, finished_scores, finished_flags, topk_seq,
+                topk_scores, topk_finished)
+            trg_word = layers.reshape(alive_seq[:, :, -1],
+                                      [batch_size * beam_size, 1])
+
+            if early_finish(alive_log_probs, finished_scores,
+                            finished_flags).numpy():
+                break
+
+        return finished_seq, finished_scores
+
+    def beam_search(self,
+                    src_word,
+                    src_pos,
+                    src_slf_attn_bias,
+                    trg_word,
+                    trg_src_attn_bias,
+                    bos_id=0,
+                    eos_id=1,
+                    beam_size=4,
+                    max_len=256):
+        if beam_size == 1:
+            return self._greedy_search(src_word,
+                                       src_pos,
+                                       src_slf_attn_bias,
+                                       trg_word,
+                                       trg_src_attn_bias,
+                                       bos_id=bos_id,
+                                       eos_id=eos_id,
+                                       max_len=max_len)
+        else:
+            return self._beam_search(src_word,
+                                     src_pos,
+                                     src_slf_attn_bias,
+                                     trg_word,
+                                     trg_src_attn_bias,
+                                     bos_id=bos_id,
+                                     eos_id=eos_id,
+                                     beam_size=beam_size,
+                                     max_len=max_len)
+
+    def _beam_search(self,
+                     src_word,
+                     src_pos,
+                     src_slf_attn_bias,
+                     trg_word,
+                     trg_src_attn_bias,
+                     bos_id=0,
+                     eos_id=1,
+                     beam_size=4,
+                     max_len=256):
+        def expand_to_beam_size(tensor, beam_size):
+            tensor = layers.reshape(tensor,
+                                    [tensor.shape[0], 1] + tensor.shape[1:])
+            tile_dims = [1] * len(tensor.shape)
+            tile_dims[1] = beam_size
+            return layers.expand(tensor, tile_dims)
+
+        def merge_batch_beams(tensor):
+            return layers.reshape(tensor, [tensor.shape[0] * tensor.shape[1]] +
+                                  tensor.shape[2:])
+
+        def split_batch_beams(tensor):
+            return layers.reshape(tensor,
+                                  shape=[-1, beam_size] +
+                                  list(tensor.shape[1:]))
+
+        def mask_probs(probs, finished, noend_mask_tensor):
+            # TODO: use where_op
+            finished = layers.cast(finished, dtype=probs.dtype)
+            probs = layers.elementwise_mul(layers.expand(
+                layers.unsqueeze(finished, [2]), [1, 1, self.trg_vocab_size]),
+                                           noend_mask_tensor,
+                                           axis=-1) - layers.elementwise_mul(
+                                               probs, (finished - 1), axis=0)
+            return probs
+
+        def gather(x, indices, batch_pos):
+            topk_coordinates = layers.stack([batch_pos, indices], axis=2)
+            return layers.gather_nd(x, topk_coordinates)
+
+        def update_states(func, caches):
+            for cache in caches:  # no need to update static_kv
+                cache["k"] = func(cache["k"])
+                cache["v"] = func(cache["v"])
+            return caches
+
+        # run encoder
+        enc_output = self.encoder(src_word, src_pos, src_slf_attn_bias)
+
+        # constant number
+        inf = float(1. * 1e7)
+        batch_size = enc_output.shape[0]
+        max_len = (enc_output.shape[1] + 20) if max_len is None else max_len
+        vocab_size_tensor = layers.fill_constant(shape=[1],
+                                                 dtype="int64",
+                                                 value=self.trg_vocab_size)
+        end_token_tensor = to_variable(
+            np.full([batch_size, beam_size], eos_id, dtype="int64"))
+        noend_array = [-inf] * self.trg_vocab_size
+        noend_array[eos_id] = 0
+        noend_mask_tensor = to_variable(np.array(noend_array,dtype="float32"))
+        batch_pos = layers.expand(
+            layers.unsqueeze(
+                to_variable(np.arange(0, batch_size, 1, dtype="int64")), [1]),
+            [1, beam_size])
+
+        predict_ids = []
+        parent_ids = []
+        ### initialize states of beam search ###
+        log_probs = to_variable(
+            np.array([[0.] + [-inf] * (beam_size - 1)] * batch_size,
+                     dtype="float32"))
+        finished = to_variable(np.full([batch_size, beam_size], 0,
+                                       dtype="bool"))
+        ### initialize inputs and states of transformer decoder ###
+        ## init inputs for decoder, shaped `[batch_size*beam_size, ...]`
+        trg_word = layers.fill_constant(shape=[batch_size * beam_size, 1],
+                                        dtype="int64",
+                                        value=bos_id)
+        trg_pos = layers.zeros_like(trg_word)
+        trg_src_attn_bias = merge_batch_beams(
+            expand_to_beam_size(trg_src_attn_bias, beam_size))
+        enc_output = merge_batch_beams(expand_to_beam_size(enc_output, beam_size))
+        ## init states (caches) for transformer, need to be updated according to selected beam
+        caches = [{
+            "k":
+            layers.fill_constant(
+                shape=[batch_size * beam_size, self.n_head, 0, self.d_key],
+                dtype=enc_output.dtype,
+                value=0),
+            "v":
+            layers.fill_constant(
+                shape=[batch_size * beam_size, self.n_head, 0, self.d_value],
+                dtype=enc_output.dtype,
+                value=0),
+        } for i in range(self.n_layer)]
+
+        for i in range(max_len):
+            trg_pos = layers.fill_constant(shape=trg_word.shape,
+                                           dtype="int64",
+                                           value=i)
+            caches = update_states(  # can not be reshaped since the 0 size
+                lambda x: x if i == 0 else merge_batch_beams(x), caches)
+            logits = self.decoder(trg_word, trg_pos, None, trg_src_attn_bias,
+                                  enc_output, caches)
+            caches = update_states(split_batch_beams, caches)
+            step_log_probs = split_batch_beams(
+                layers.log(layers.softmax(logits)))
+            step_log_probs = mask_probs(step_log_probs, finished,
+                                        noend_mask_tensor)
+            log_probs = layers.elementwise_add(x=step_log_probs,
+                                               y=log_probs,
+                                               axis=0)
+            log_probs = layers.reshape(log_probs,
+                                       [-1, beam_size * self.trg_vocab_size])
+            scores = log_probs
+            topk_scores, topk_indices = layers.topk(input=scores, k=beam_size)
+            beam_indices = layers.elementwise_floordiv(
+                topk_indices, vocab_size_tensor)
+            token_indices = layers.elementwise_mod(
+                topk_indices, vocab_size_tensor)
+
+            # update states
+            caches = update_states(lambda x: gather(x, beam_indices, batch_pos),
+                                   caches)
+            log_probs = gather(log_probs, topk_indices, batch_pos)
+            finished = gather(finished, beam_indices, batch_pos)
+            finished = layers.logical_or(
+                finished, layers.equal(token_indices, end_token_tensor))
+            trg_word = layers.reshape(token_indices, [-1, 1])
+
+            predict_ids.append(token_indices)
+            parent_ids.append(beam_indices)
+
+            if layers.reduce_all(finished).numpy():
+                break
+
+        predict_ids = layers.stack(predict_ids, axis=0)
+        parent_ids = layers.stack(parent_ids, axis=0)
+        finished_seq = layers.transpose(
+            layers.gather_tree(predict_ids, parent_ids), [1, 2, 0])
+        finished_scores = topk_scores
+
+        return finished_seq, finished_scores
+
+    def _greedy_search(self,
+                       src_word,
+                       src_pos,
+                       src_slf_attn_bias,
+                       trg_word,
+                       trg_src_attn_bias,
+                       bos_id=0,
+                       eos_id=1,
+                       max_len=256):
+        # run encoder
+        enc_output = self.encoder(src_word, src_pos, src_slf_attn_bias)
+
+        # constant number
+        batch_size = enc_output.shape[0]
+        max_len = (enc_output.shape[1] + 20) if max_len is None else max_len
+        end_token_tensor = layers.fill_constant(shape=[batch_size, 1],
+                                                dtype="int64",
+                                                value=eos_id)
+
+        predict_ids = []
+        log_probs = layers.fill_constant(shape=[batch_size, 1],
+                                         dtype="float32",
+                                         value=0)
+        trg_word = layers.fill_constant(shape=[batch_size, 1],
+                                        dtype="int64",
+                                        value=bos_id)
+        finished = layers.fill_constant(shape=[batch_size, 1],
+                                        dtype="bool",
+                                        value=0)
+
+        ## init states (caches) for transformer
+        caches = [{
+            "k":
+            layers.fill_constant(
+                shape=[batch_size, self.n_head, 0, self.d_key],
+                dtype=enc_output.dtype,
+                value=0),
+            "v":
+            layers.fill_constant(
+                shape=[batch_size, self.n_head, 0, self.d_value],
+                dtype=enc_output.dtype,
+                value=0),
+        } for i in range(self.n_layer)]
+
+        for i in range(max_len):
+            trg_pos = layers.fill_constant(shape=trg_word.shape,
+                                           dtype="int64",
+                                           value=i)
+            logits = self.decoder(trg_word, trg_pos, None, trg_src_attn_bias,
+                                  enc_output, caches)
+            step_log_probs = layers.log(layers.softmax(logits))
+            log_probs = layers.elementwise_add(x=step_log_probs,
+                                               y=log_probs,
+                                               axis=0)
+            scores = log_probs
+            topk_scores, topk_indices = layers.topk(input=scores, k=1)
+
+            finished = layers.logical_or(
+                finished, layers.equal(topk_indices, end_token_tensor))
+            trg_word = topk_indices
+            log_probs = topk_scores
+
+            predict_ids.append(topk_indices)
+
+            if layers.reduce_all(finished).numpy():
+                break
+
+        predict_ids = layers.stack(predict_ids, axis=0)
+        finished_seq = layers.transpose(predict_ids, [1, 2, 0])
+        finished_scores = topk_scores
+
+        return finished_seq, finished_scores
diff --git a/transformer/transformer.yaml b/transformer/transformer.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..60e33242f937a5bdd2cb1a01357d4fa1bee9a113
--- /dev/null
+++ b/transformer/transformer.yaml
@@ -0,0 +1,113 @@
+# used for continuous evaluation
+enable_ce: False
+
+eager_run: False
+num_devices: 1
+
+# The frequency to save trained models when training.
+save_step: 10000
+# The frequency to fetch and print output when training.
+print_step: 100
+# path of the checkpoint, to resume the previous training
+init_from_checkpoint: ""
+# path of the pretrain model, to better solve the current task
+init_from_pretrain_model: ""
+# path of trained parameter, to make prediction
+init_from_params: "trained_params/step_100000/"
+# the directory for saving model
+save_model: "trained_models"
+# the directory for saving inference model.
+inference_model_dir: "infer_model"
+# Set seed for CE or debug
+random_seed: None
+# The pattern to match training data files.
+training_file: "wmt16_ende_data_bpe/train.tok.clean.bpe.32000.en-de"
+# The pattern to match validation data files.
+validation_file: "wmt16_ende_data_bpe/newstest2014.tok.bpe.32000.en-de"
+# The pattern to match test data files.
+predict_file: "wmt16_ende_data_bpe/newstest2016.tok.bpe.32000.en-de"
+# The file to output the translation results of predict_file to.
+output_file: "predict.txt"
+# The path of vocabulary file of source language.
+src_vocab_fpath: "wmt16_ende_data_bpe/vocab_all.bpe.32000"
+# The path of vocabulary file of target language.
+trg_vocab_fpath: "wmt16_ende_data_bpe/vocab_all.bpe.32000"
+# The <bos>, <eos> and <unk> tokens in the dictionary.
+special_token: ["<s>", "<e>", "<unk>"]
+
+# whether to use cuda
+use_cuda: True
+
+# args for reader, see reader.py for details
+token_delimiter: " "
+use_token_batch: True
+pool_size: 200000
+sort_type: "pool"
+shuffle: True
+shuffle_batch: True
+batch_size: 4096
+
+# Hyparams for training:
+# the number of epoches for training
+epoch: 30
+# the hyper parameters for Adam optimizer.
+# This static learning_rate will be multiplied to the LearningRateScheduler
+# derived learning rate the to get the final learning rate.
+learning_rate: 2.0
+beta1: 0.9
+beta2: 0.997
+eps: 1e-9
+# the parameters for learning rate scheduling.
+warmup_steps: 8000
+# the weight used to mix up the ground-truth distribution and the fixed
+# uniform distribution in label smoothing when training.
+# Set this as zero if label smoothing is not wanted.
+label_smooth_eps: 0.1
+
+# Hyparams for generation:
+# the parameters for beam search.
+beam_size: 5
+max_out_len: 256
+# the number of decoded sentences to output.
+n_best: 1
+
+# Hyparams for model:
+# These following five vocabularies related configurations will be set
+# automatically according to the passed vocabulary path and special tokens.
+# size of source word dictionary.
+src_vocab_size: 10000
+# size of target word dictionay
+trg_vocab_size: 10000
+# index for <bos> token
+bos_idx: 0
+# index for <eos> token
+eos_idx: 1
+# index for <unk> token
+unk_idx: 2
+# max length of sequences deciding the size of position encoding table.
+max_length: 256
+# the dimension for word embeddings, which is also the last dimension of
+# the input and output of multi-head attention, position-wise feed-forward
+# networks, encoder and decoder.
+d_model: 512
+# size of the hidden layer in position-wise feed-forward networks.
+d_inner_hid: 2048
+# the dimension that keys are projected to for dot-product attention.
+d_key: 64
+# the dimension that values are projected to for dot-product attention.
+d_value: 64
+# number of head used in multi-head attention.
+n_head: 8
+# number of sub-layers to be stacked in the encoder and decoder.
+n_layer: 6
+# dropout rates of different modules.
+prepostprocess_dropout: 0.1
+attention_dropout: 0.1
+relu_dropout: 0.1
+# to process before each sub-layer
+preprocess_cmd: "n"  # layer normalization
+# to process after each sub-layer
+postprocess_cmd: "da"  # dropout + residual connection
+# the flag indicating whether to share embedding and softmax weights.
+# vocabularies in source and target should be same for weight sharing.
+weight_sharing: True
diff --git a/transformer/utils/__init__.py b/transformer/utils/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/transformer/utils/check.py b/transformer/utils/check.py
new file mode 100644
index 0000000000000000000000000000000000000000..305fa3705f5c313569986cbdb15c8afeda5a79c1
--- /dev/null
+++ b/transformer/utils/check.py
@@ -0,0 +1,61 @@
+# Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import sys
+
+import paddle.fluid as fluid
+
+import logging
+logger = logging.getLogger(__name__)
+
+__all__ = ['check_gpu', 'check_version']
+
+
+def check_gpu(use_gpu):
+    """
+    Log error and exit when set use_gpu=true in paddlepaddle
+    cpu version.
+    """
+    err = "Config use_gpu cannot be set as true while you are " \
+          "using paddlepaddle cpu version ! \nPlease try: \n" \
+          "\t1. Install paddlepaddle-gpu to run model on GPU \n" \
+          "\t2. Set use_gpu as false in config file to run " \
+          "model on CPU"
+
+    try:
+        if use_gpu and not fluid.is_compiled_with_cuda():
+            logger.error(err)
+            sys.exit(1)
+    except Exception as e:
+        pass
+
+
+def check_version():
+    """
+    Log error and exit when the installed version of paddlepaddle is
+    not satisfied.
+    """
+    err = "PaddlePaddle version 1.6 or higher is required, " \
+          "or a suitable develop version is satisfied as well. \n" \
+          "Please make sure the version is good with your code." \
+
+    try:
+        fluid.require_version('1.6.0')
+    except Exception as e:
+        logger.error(err)
+        sys.exit(1)
diff --git a/transformer/utils/configure.py b/transformer/utils/configure.py
new file mode 100644
index 0000000000000000000000000000000000000000..67e601282fee572518435eaed38a4ed8e26fc5f9
--- /dev/null
+++ b/transformer/utils/configure.py
@@ -0,0 +1,350 @@
+# Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import os
+import sys
+import argparse
+import json
+import yaml
+import six
+import logging
+
+logging_only_message = "%(message)s"
+logging_details = "%(asctime)s.%(msecs)03d %(levelname)s %(module)s - %(funcName)s: %(message)s"
+
+
+class JsonConfig(object):
+    """
+    A high-level api for handling json configure file.
+    """
+
+    def __init__(self, config_path):
+        self._config_dict = self._parse(config_path)
+
+    def _parse(self, config_path):
+        try:
+            with open(config_path) as json_file:
+                config_dict = json.load(json_file)
+        except:
+            raise IOError("Error in parsing bert model config file '%s'" %
+                          config_path)
+        else:
+            return config_dict
+
+    def __getitem__(self, key):
+        return self._config_dict[key]
+
+    def print_config(self):
+        for arg, value in sorted(six.iteritems(self._config_dict)):
+            print('%s: %s' % (arg, value))
+        print('------------------------------------------------')
+
+
+class ArgumentGroup(object):
+    def __init__(self, parser, title, des):
+        self._group = parser.add_argument_group(title=title, description=des)
+
+    def add_arg(self, name, type, default, help, **kwargs):
+        type = str2bool if type == bool else type
+        self._group.add_argument(
+            "--" + name,
+            default=default,
+            type=type,
+            help=help + ' Default: %(default)s.',
+            **kwargs)
+
+
+class ArgConfig(object):
+    """
+    A high-level api for handling argument configs.
+    """
+
+    def __init__(self):
+        parser = argparse.ArgumentParser()
+
+        train_g = ArgumentGroup(parser, "training", "training options.")
+        train_g.add_arg("epoch", int, 3, "Number of epoches for fine-tuning.")
+        train_g.add_arg("learning_rate", float, 5e-5,
+                        "Learning rate used to train with warmup.")
+        train_g.add_arg(
+            "lr_scheduler",
+            str,
+            "linear_warmup_decay",
+            "scheduler of learning rate.",
+            choices=['linear_warmup_decay', 'noam_decay'])
+        train_g.add_arg("weight_decay", float, 0.01,
+                        "Weight decay rate for L2 regularizer.")
+        train_g.add_arg(
+            "warmup_proportion", float, 0.1,
+            "Proportion of training steps to perform linear learning rate warmup for."
+        )
+        train_g.add_arg("save_steps", int, 1000,
+                        "The steps interval to save checkpoints.")
+        train_g.add_arg("use_fp16", bool, False,
+                        "Whether to use fp16 mixed precision training.")
+        train_g.add_arg(
+            "loss_scaling", float, 1.0,
+            "Loss scaling factor for mixed precision training, only valid when use_fp16 is enabled."
+        )
+        train_g.add_arg("pred_dir", str, None,
+                        "Path to save the prediction results")
+
+        log_g = ArgumentGroup(parser, "logging", "logging related.")
+        log_g.add_arg("skip_steps", int, 10,
+                      "The steps interval to print loss.")
+        log_g.add_arg("verbose", bool, False, "Whether to output verbose log.")
+
+        run_type_g = ArgumentGroup(parser, "run_type", "running type options.")
+        run_type_g.add_arg("use_cuda", bool, True,
+                           "If set, use GPU for training.")
+        run_type_g.add_arg(
+            "use_fast_executor", bool, False,
+            "If set, use fast parallel executor (in experiment).")
+        run_type_g.add_arg(
+            "num_iteration_per_drop_scope", int, 1,
+            "Ihe iteration intervals to clean up temporary variables.")
+        run_type_g.add_arg("do_train", bool, True,
+                           "Whether to perform training.")
+        run_type_g.add_arg("do_predict", bool, True,
+                           "Whether to perform prediction.")
+
+        custom_g = ArgumentGroup(parser, "customize", "customized options.")
+
+        self.custom_g = custom_g
+
+        self.parser = parser
+
+    def add_arg(self, name, dtype, default, descrip):
+        self.custom_g.add_arg(name, dtype, default, descrip)
+
+    def build_conf(self):
+        return self.parser.parse_args()
+
+
+def str2bool(v):
+    # because argparse does not support to parse "true, False" as python
+    # boolean directly
+    return v.lower() in ("true", "t", "1")
+
+
+def print_arguments(args, log=None):
+    if not log:
+        print('-----------  Configuration Arguments -----------')
+        for arg, value in sorted(six.iteritems(vars(args))):
+            print('%s: %s' % (arg, value))
+        print('------------------------------------------------')
+    else:
+        log.info('-----------  Configuration Arguments -----------')
+        for arg, value in sorted(six.iteritems(vars(args))):
+            log.info('%s: %s' % (arg, value))
+        log.info('------------------------------------------------')
+
+
+class PDConfig(object):
+    """
+    A high-level API for managing configuration files in PaddlePaddle.
+    Can jointly work with command-line-arugment, json files and yaml files.
+    """
+
+    def __init__(self, json_file="", yaml_file="", fuse_args=True):
+        """
+            Init funciton for PDConfig.
+            json_file: the path to the json configure file.
+            yaml_file: the path to the yaml configure file.
+            fuse_args: if fuse the json/yaml configs with argparse.
+        """
+        assert isinstance(json_file, str)
+        assert isinstance(yaml_file, str)
+
+        if json_file != "" and yaml_file != "":
+            raise Warning(
+                "json_file and yaml_file can not co-exist for now. please only use one configure file type."
+            )
+            return
+
+        self.args = None
+        self.arg_config = {}
+        self.json_config = {}
+        self.yaml_config = {}
+
+        parser = argparse.ArgumentParser()
+
+        self.default_g = ArgumentGroup(parser, "default", "default options.")
+        self.yaml_g = ArgumentGroup(parser, "yaml", "options from yaml.")
+        self.json_g = ArgumentGroup(parser, "json", "options from json.")
+        self.com_g = ArgumentGroup(parser, "custom", "customized options.")
+
+        self.default_g.add_arg("do_train", bool, False,
+                               "Whether to perform training.")
+        self.default_g.add_arg("do_predict", bool, False,
+                               "Whether to perform predicting.")
+        self.default_g.add_arg("do_eval", bool, False,
+                               "Whether to perform evaluating.")
+        self.default_g.add_arg("do_save_inference_model", bool, False,
+                               "Whether to perform model saving for inference.")
+
+        # NOTE: args for profiler
+        self.default_g.add_arg("is_profiler", int, 0, "the switch of profiler tools. (used for benchmark)")
+        self.default_g.add_arg("profiler_path", str, './', "the profiler output file path. (used for benchmark)")
+        self.default_g.add_arg("max_iter", int, 0, "the max train batch num.(used for benchmark)")
+
+        self.parser = parser
+
+        if json_file != "":
+            self.load_json(json_file, fuse_args=fuse_args)
+
+        if yaml_file:
+            self.load_yaml(yaml_file, fuse_args=fuse_args)
+
+    def load_json(self, file_path, fuse_args=True):
+
+        if not os.path.exists(file_path):
+            raise Warning("the json file %s does not exist." % file_path)
+            return
+
+        with open(file_path, "r") as fin:
+            self.json_config = json.loads(fin.read())
+            fin.close()
+
+        if fuse_args:
+            for name in self.json_config:
+                if isinstance(self.json_config[name], list):
+                    self.json_g.add_arg(
+                        name,
+                        type(self.json_config[name][0]),
+                        self.json_config[name],
+                        "This is from %s" % file_path,
+                        nargs=len(self.json_config[name]))
+                    continue
+                if not isinstance(self.json_config[name], int) \
+                    and not isinstance(self.json_config[name], float) \
+                    and not isinstance(self.json_config[name], str) \
+                    and not isinstance(self.json_config[name], bool):
+
+                    continue
+
+                self.json_g.add_arg(name,
+                                    type(self.json_config[name]),
+                                    self.json_config[name],
+                                    "This is from %s" % file_path)
+
+    def load_yaml(self, file_path, fuse_args=True):
+
+        if not os.path.exists(file_path):
+            raise Warning("the yaml file %s does not exist." % file_path)
+            return
+
+        with open(file_path, "r") as fin:
+            self.yaml_config = yaml.load(fin, Loader=yaml.SafeLoader)
+            fin.close()
+
+        if fuse_args:
+            for name in self.yaml_config:
+                if isinstance(self.yaml_config[name], list):
+                    self.yaml_g.add_arg(
+                        name,
+                        type(self.yaml_config[name][0]),
+                        self.yaml_config[name],
+                        "This is from %s" % file_path,
+                        nargs=len(self.yaml_config[name]))
+                    continue
+
+                if not isinstance(self.yaml_config[name], int) \
+                    and not isinstance(self.yaml_config[name], float) \
+                    and not isinstance(self.yaml_config[name], str) \
+                    and not isinstance(self.yaml_config[name], bool):
+
+                    continue
+
+                self.yaml_g.add_arg(name,
+                                    type(self.yaml_config[name]),
+                                    self.yaml_config[name],
+                                    "This is from %s" % file_path)
+
+    def build(self):
+        self.args = self.parser.parse_args()
+        self.arg_config = vars(self.args)
+
+    def __add__(self, new_arg):
+        assert isinstance(new_arg, list) or isinstance(new_arg, tuple)
+        assert len(new_arg) >= 3
+        assert self.args is None
+
+        name = new_arg[0]
+        dtype = new_arg[1]
+        dvalue = new_arg[2]
+        desc = new_arg[3] if len(
+            new_arg) == 4 else "Description is not provided."
+
+        self.com_g.add_arg(name, dtype, dvalue, desc)
+
+        return self
+
+    def __getattr__(self, name):
+        if name in self.arg_config:
+            return self.arg_config[name]
+
+        if name in self.json_config:
+            return self.json_config[name]
+
+        if name in self.yaml_config:
+            return self.yaml_config[name]
+
+        raise Warning("The argument %s is not defined." % name)
+
+    def Print(self):
+
+        print("-" * 70)
+        for name in self.arg_config:
+            print("%s:\t\t\t\t%s" % (str(name), str(self.arg_config[name])))
+
+        for name in self.json_config:
+            if name not in self.arg_config:
+                print("%s:\t\t\t\t%s" %
+                      (str(name), str(self.json_config[name])))
+
+        for name in self.yaml_config:
+            if name not in self.arg_config:
+                print("%s:\t\t\t\t%s" %
+                      (str(name), str(self.yaml_config[name])))
+
+        print("-" * 70)
+
+
+if __name__ == "__main__":
+    """
+    pd_config = PDConfig(json_file = "./test/bert_config.json")
+    pd_config.build()
+
+    print(pd_config.do_train)
+    print(pd_config.hidden_size)
+
+    pd_config = PDConfig(yaml_file = "./test/bert_config.yaml")
+    pd_config.build()
+
+    print(pd_config.do_train)
+    print(pd_config.hidden_size)
+    """
+
+    pd_config = PDConfig(yaml_file="./test/bert_config.yaml")
+    pd_config += ("my_age", int, 18, "I am forever 18.")
+    pd_config.build()
+
+    print(pd_config.do_train)
+    print(pd_config.hidden_size)
+    print(pd_config.my_age)