13 KiB
目录
Transformer 概述
Transformer于2017年提出,用于处理序列数据。Transformer主要应用于自然语言处理(NLP)领域,如机器翻译或文本摘要等任务。不同于传统的循环神经网络按次序处理数据,Transformer采用注意力机制,提高并行,减少训练次数,从而实现在较大数据集上训练。自Transformer模型引入以来,许多NLP中出现的问题得以解决,衍生出众多网络模型,比如BERT(多层双向transformer编码器)和GPT(生成式预训练transformers) 。
论文: Ashish Vaswani, Noam Shazeer, Niki Parmar, JakobUszkoreit, Llion Jones, Aidan N Gomez, Ł ukaszKaiser, and Illia Polosukhin. 2017. Attention is all you need. In NIPS 2017, pages 5998–6008.
模型架构
Transformer具体包括六个编码模块和六个解码模块。每个编码模块由一个自注意层和一个前馈层组成,每个解码模块由一个自注意层,一个编码-解码-注意层和一个前馈层组成。
数据集
- 训练数据集WMT English-German
- 评估数据集WMT newstest2014
环境要求
- 硬件(Ascend处理器)
- 使用Ascend处理器准备硬件环境。
- 框架
- 如需查看详情,请参见如下资源:
快速入门
数据集准备完成后,请按照如下步骤开始训练和评估:
# 运行训练示例
sh scripts/run_standalone_train_ascend.sh 0 52 /path/ende-l128-mindrecord
# 运行分布式训练示例
sh scripts/run_distribute_train_ascend.sh 8 52 /path/ende-l128-mindrecord rank_table.json
# 运行评估示例
python eval.py > eval.log 2>&1 &
脚本说明
脚本和样例代码
.
└─Transformer
├─README.md
├─scripts
├─process_output.sh
├─replace-quote.perl
├─run_distribute_train_ascend.sh
└─run_standalone_train_ascend.sh
├─src
├─__init__.py
├─beam_search.py
├─config.py
├─dataset.py
├─eval_config.py
├─lr_schedule.py
├─process_output.py
├─tokenization.py
├─transformer_for_train.py
├─transformer_model.py
└─weight_init.py
├─create_data.py
├─eval.py
└─train.py
脚本参数
训练脚本参数
usage: train.py [--distribute DISTRIBUTE] [--epoch_size N] [----device_num N] [--device_id N]
[--enable_save_ckpt ENABLE_SAVE_CKPT]
[--enable_lossscale ENABLE_LOSSSCALE] [--do_shuffle DO_SHUFFLE]
[--save_checkpoint_steps N] [--save_checkpoint_num N]
[--save_checkpoint_path SAVE_CHECKPOINT_PATH]
[--data_path DATA_PATH] [--bucket_boundaries BUCKET_LENGTH]
options:
--distribute pre_training by several devices: "true"(training by more than 1 device) | "false", default is "false"
--epoch_size epoch size: N, default is 52
--device_num number of used devices: N, default is 1
--device_id device id: N, default is 0
--enable_save_ckpt enable save checkpoint: "true" | "false", default is "true"
--enable_lossscale enable lossscale: "true" | "false", default is "true"
--do_shuffle enable shuffle: "true" | "false", default is "true"
--checkpoint_path path to load checkpoint files: PATH, default is ""
--save_checkpoint_steps steps for saving checkpoint files: N, default is 2500
--save_checkpoint_num number for saving checkpoint files: N, default is 30
--save_checkpoint_path path to save checkpoint files: PATH, default is "./checkpoint/"
--data_path path to dataset file: PATH, default is ""
--bucket_boundaries sequence lengths for different bucket: LIST, default is [16, 32, 48, 64, 128]
运行选项
config.py:
transformer_network version of Transformer model: base | large, default is large
init_loss_scale_value initial value of loss scale: N, default is 2^10
scale_factor factor used to update loss scale: N, default is 2
scale_window steps for once updatation of loss scale: N, default is 2000
optimizer optimizer used in the network: Adam, default is "Adam"
eval_config.py:
transformer_network version of Transformer model: base | large, default is large
data_file data file: PATH
model_file checkpoint file to be loaded: PATH
output_file output file of evaluation: PATH
网络参数
Parameters for dataset and network (Training/Evaluation):
batch_size batch size of input dataset: N, default is 96
seq_length max length of input sequence: N, default is 128
vocab_size size of each embedding vector: N, default is 36560
hidden_size size of Transformer encoder layers: N, default is 1024
num_hidden_layers number of hidden layers: N, default is 6
num_attention_heads number of attention heads: N, default is 16
intermediate_size size of intermediate layer: N, default is 4096
hidden_act activation function used: ACTIVATION, default is "relu"
hidden_dropout_prob dropout probability for TransformerOutput: Q, default is 0.3
attention_probs_dropout_prob dropout probability for TransformerAttention: Q, default is 0.3
max_position_embeddings maximum length of sequences: N, default is 128
initializer_range initialization value of TruncatedNormal: Q, default is 0.02
label_smoothing label smoothing setting: Q, default is 0.1
input_mask_from_dataset use the input mask loaded form dataset or not: True | False, default is True
beam_width beam width setting: N, default is 4
max_decode_length max decode length in evaluation: N, default is 80
length_penalty_weight normalize scores of translations according to their length: Q, default is 1.0
compute_type compute type in Transformer: mstype.float16 | mstype.float32, default is mstype.float16
Parameters for learning rate:
learning_rate value of learning rate: Q
warmup_steps steps of the learning rate warm up: N
start_decay_step step of the learning rate to decay: N
min_lr minimal learning rate: Q
准备数据集
-
您可以使用Shell脚本下载并预处理WMT英-德翻译数据集。假设您已获得下列文件:
- train.tok.clean.bpe.32000.en
- train.tok.clean.bpe.32000.de
- vocab.bpe.32000
- newstest2014.tok.bpe.32000.en
- newstest2014.tok.bpe.32000.de
- newstest2014.tok.de
-
将原数据转换为MindRecord数据格式进行训练:
paste train.tok.clean.bpe.32000.en train.tok.clean.bpe.32000.de > train.all python create_data.py --input_file train.all --vocab_file vocab.bpe.32000 --output_file /path/ende-l128-mindrecord --max_seq_length 128 --bucket [16,32,48,64,128]
-
将原数据转化为MindRecord数据格式进行评估:
paste newstest2014.tok.bpe.32000.en newstest2014.tok.bpe.32000.de > test.all python create_data.py --input_file test.all --vocab_file vocab.bpe.32000 --output_file /path/newstest2014-l128-mindrecord --num_splits 1 --max_seq_length 128 --clip_to_max_len True --bucket [128]
训练过程
-
在
config.py
中设置选项,包括loss_scale、学习率和网络超参数。点击这里查看更多数据集信息。 -
运行
run_standalone_train.sh
,进行Transformer模型的非分布式训练。sh scripts/run_standalone_train.sh DEVICE_TARGET DEVICE_ID EPOCH_SIZE DATA_PATH
-
运行
run_distribute_train_ascend.sh
,进行Transformer模型的非分布式训练。sh scripts/run_distribute_train_ascend.sh DEVICE_NUM EPOCH_SIZE DATA_PATH RANK_TABLE_FILE
注意:由于网络输入中有不同句长的数据,所以数据下沉模式不可使用。
评估过程
-
在
eval_config.py
中设置选项。确保已设置了‘data_file'、'model_file’和'output_file'文件路径。 -
运行
eval.py
,评估Transformer模型。python eval.py
-
运行
process_output.sh
,处理输出标记ids,获得真实翻译结果。sh scripts/process_output.sh REF_DATA EVAL_OUTPUT VOCAB_FILE
您将会获得REF_DATA.forbleu和EVAL_OUTPUT.forbleu两个文件来进行BLEU分数计算。
-
如需计算BLEU分数,详情参见perl脚本,并运行一下命令获得BLEU分数。
perl multi-bleu.perl REF_DATA.forbleu < EVAL_OUTPUT.forbleu
模型描述
性能
训练性能
参数 | Ascend |
---|---|
资源 | Ascend 910 |
上传日期 | 2020-06-09 |
MindSpore版本 | 0.5.0-beta |
数据集 | WMT英-德翻译数据集 |
训练参数 | epoch=52, batch_size=96 |
优化器 | Adam |
损失函数 | Softmax Cross Entropy |
BLEU分数 | 28.7 |
速度 | 400毫秒/步(8卡) |
损失 | 2.8 |
参数 (M) | 213.7 |
推理检查点 | 2.4G (.ckpt文件) |
脚本 | https://gitee.com/mindspore/mindspore/tree/master/model_zoo/official/nlp/transformer |
评估性能
参数 | Ascend |
---|---|
资源 | Ascend 910 |
上传日期 | 2020-06-09 |
MindSpore版本 | 0.5.0-beta |
数据集 | WMT newstest2014 |
batch_size | 1 |
输出 | BLEU score |
准确率 | BLEU=28.7 |
随机情况说明
以下三种随机情况:
- 轮换数据集
- 初始化部分模型权重
- 随机失活运行
train.py已经设置了一些种子,避免数据集轮换和权重初始化的随机性。若需关闭随机失活,将src/config.py中相应的dropout_prob参数设置为0。
ModelZoo主页
请浏览官网主页。