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Seq2SeqTrainer (#6769)

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Co-authored-by: Sam Shleifer <sshleifer@gmail.com>
This commit is contained in:
Suraj Patil
2020-09-25 04:16:58 +05:30
committed by GitHub
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import json
import logging
import os
import sys
from dataclasses import dataclass, field
from typing import Callable, Dict, List, Optional, Tuple
import numpy as np
import torch
from seq2seq_trainer import Seq2SeqTrainer
from transformers import (
AutoConfig,
AutoModelForSeq2SeqLM,
AutoTokenizer,
BartTokenizer,
EvalPrediction,
HfArgumentParser,
MBartTokenizer,
T5Tokenizer,
TrainingArguments,
set_seed,
)
from transformers.modeling_bart import shift_tokens_right
from utils import (
LegacySeq2SeqDataset,
Seq2SeqDataset,
assert_all_frozen,
calculate_bleu,
calculate_rouge,
freeze_params,
lmap,
trim_batch,
use_task_specific_params,
)
logger = logging.getLogger(__name__)
class Seq2SeqDataCollator:
def __init__(self, tokenizer, data_args, tpu_num_cores=None):
self.tokenizer = tokenizer
self.pad_token_id = tokenizer.pad_token_id
self.data_args = data_args
self.tpu_num_cores = tpu_num_cores
self.add_prefix_space = isinstance(tokenizer, BartTokenizer)
def __call__(self, batch) -> Dict[str, torch.Tensor]:
if hasattr(self.tokenizer, "prepare_seq2seq_batch"):
batch = self._encode(batch)
input_ids, attention_mask, labels = (
batch["input_ids"],
batch["attention_mask"],
batch["labels"],
)
else:
input_ids = torch.stack([x["input_ids"] for x in batch])
attention_mask = torch.stack([x["attention_mask"] for x in batch])
labels = torch.stack([x["labels"] for x in batch])
labels = trim_batch(labels, self.pad_token_id)
input_ids, attention_mask = trim_batch(input_ids, self.pad_token_id, attention_mask=attention_mask)
if isinstance(self.tokenizer, T5Tokenizer):
decoder_input_ids = self._shift_right_t5(labels)
labels = labels
else:
decoder_input_ids = shift_tokens_right(labels, self.pad_token_id)
labels = labels
batch = {
"input_ids": input_ids,
"attention_mask": attention_mask,
"decoder_input_ids": decoder_input_ids,
"labels": labels,
}
return batch
def _shift_right_t5(self, input_ids):
decoder_start_token_id = self.pad_token_id
assert (
decoder_start_token_id is not None
), "self.model.config.decoder_start_token_id has to be defined. In T5 it is usually set to the pad_token_id. See T5 docs for more information"
# shift inputs to the right
shifted_input_ids = input_ids.new_zeros(input_ids.shape)
shifted_input_ids[..., 1:] = input_ids[..., :-1].clone()
shifted_input_ids[..., 0] = decoder_start_token_id
return shifted_input_ids
def _encode(self, batch) -> Dict[str, torch.Tensor]:
batch_encoding = self.tokenizer.prepare_seq2seq_batch(
[x["src_texts"] for x in batch],
src_lang=self.data_args.src_lang,
tgt_texts=[x["tgt_texts"] for x in batch],
tgt_lang=self.data_args.tgt_lang,
max_length=self.data_args.max_source_length,
max_target_length=self.data_args.max_target_length,
padding="max_length" if self.tpu_num_cores is not None else "longest", # TPU hack
return_tensors="pt",
add_prefix_space=self.add_prefix_space,
)
return batch_encoding.data
@dataclass
class Seq2SeqTrainingArguments(TrainingArguments):
"""
Parameters:
label_smoothing (:obj:`float`, `optional`, defaults to 0):
The label smoothing epsilon to apply (if not zero).
sortish_sampler (:obj:`bool`, `optional`, defaults to :obj:`False`):
Whether to SortishSamler or not. It sorts the inputs according to lenghts in-order to minimizing the padding size.
predict_with_generate (:obj:`bool`, `optional`, defaults to :obj:`False`):
Whether to use generate to calculate generative metrics (ROUGE, BLEU).
"""
label_smoothing: Optional[float] = field(
default=0.0, metadata={"help": "The label smoothing epsilon to apply (if not zero)."}
)
sortish_sampler: bool = field(default=False, metadata={"help": "Whether to SortishSamler or not."})
predict_with_generate: bool = field(
default=False, metadata={"help": "Whether to use generate to calculate generative metrics (ROUGE, BLEU)."}
)
@dataclass
class ModelArguments:
"""
Arguments pertaining to which model/config/tokenizer we are going to fine-tune from.
"""
model_name_or_path: str = field(
metadata={"help": "Path to pretrained model or model identifier from huggingface.co/models"}
)
config_name: Optional[str] = field(
default=None, metadata={"help": "Pretrained config name or path if not the same as model_name"}
)
tokenizer_name: Optional[str] = field(
default=None, metadata={"help": "Pretrained tokenizer name or path if not the same as model_name"}
)
cache_dir: Optional[str] = field(
default=None, metadata={"help": "Where do you want to store the pretrained models downloaded from s3"}
)
freeze_encoder: bool = field(default=False, metadata={"help": "Whether tp freeze the encoder."})
freeze_embeds: bool = field(default=False, metadata={"help": "Whether to freeze the embeddings."})
@dataclass
class DataTrainingArguments:
"""
Arguments pertaining to what data we are going to input our model for training and eval.
"""
data_dir: str = field(
metadata={"help": "The input data dir. Should contain the .tsv files (or other data files) for the task."}
)
task: Optional[str] = field(
default="summarization",
metadata={"help": "Task name, summarization (or summarization_{dataset} for pegasus) or translation"},
)
max_source_length: Optional[int] = field(
default=1024,
metadata={
"help": "The maximum total input sequence length after tokenization. Sequences longer "
"than this will be truncated, sequences shorter will be padded."
},
)
max_target_length: Optional[int] = field(
default=128,
metadata={
"help": "The maximum total sequence length for target text after tokenization. Sequences longer "
"than this will be truncated, sequences shorter will be padded."
},
)
val_max_target_length: Optional[int] = field(
default=142,
metadata={
"help": "The maximum total sequence length for validation target text after tokenization. Sequences longer "
"than this will be truncated, sequences shorter will be padded."
},
)
test_max_target_length: Optional[int] = field(
default=142,
metadata={
"help": "The maximum total sequence length for test target text after tokenization. Sequences longer "
"than this will be truncated, sequences shorter will be padded."
},
)
n_train: Optional[int] = field(default=-1, metadata={"help": "# training examples. -1 means use all."})
n_val: Optional[int] = field(default=-1, metadata={"help": "# validation examples. -1 means use all."})
n_test: Optional[int] = field(default=-1, metadata={"help": "# test examples. -1 means use all."})
src_lang: Optional[str] = field(default=None, metadata={"help": "Source language id for translation."})
tgt_lang: Optional[str] = field(default=None, metadata={"help": "Target language id for translation."})
eval_beams: Optional[int] = field(default=None, metadata={"help": "# num_beams to use for evaluation."})
def main():
# See all possible arguments in src/transformers/training_args.py
# or by passing the --help flag to this script.
# We now keep distinct sets of args, for a cleaner separation of concerns.
parser = HfArgumentParser((ModelArguments, DataTrainingArguments, Seq2SeqTrainingArguments))
if len(sys.argv) == 2 and sys.argv[1].endswith(".json"):
# If we pass only one argument to the script and it's the path to a json file,
# let's parse it to get our arguments.
model_args, data_args, training_args = parser.parse_json_file(json_file=os.path.abspath(sys.argv[1]))
else:
model_args, data_args, training_args = parser.parse_args_into_dataclasses()
if (
os.path.exists(training_args.output_dir)
and os.listdir(training_args.output_dir)
and training_args.do_train
and not training_args.overwrite_output_dir
):
raise ValueError(
f"Output directory ({training_args.output_dir}) already exists and is not empty. Use --overwrite_output_dir to overcome."
)
# Setup logging
logging.basicConfig(
format="%(asctime)s - %(levelname)s - %(name)s - %(message)s",
datefmt="%m/%d/%Y %H:%M:%S",
level=logging.INFO if training_args.local_rank in [-1, 0] else logging.WARN,
)
logger.warning(
"Process rank: %s, device: %s, n_gpu: %s, distributed training: %s, 16-bits training: %s",
training_args.local_rank,
training_args.device,
training_args.n_gpu,
bool(training_args.local_rank != -1),
training_args.fp16,
)
logger.info("Training/evaluation parameters %s", training_args)
# Set seed
set_seed(training_args.seed)
# Load pretrained model and tokenizer
#
# Distributed training:
# The .from_pretrained methods guarantee that only one local process can concurrently
# download model & vocab.
config = AutoConfig.from_pretrained(
model_args.config_name if model_args.config_name else model_args.model_name_or_path,
cache_dir=model_args.cache_dir,
)
tokenizer = AutoTokenizer.from_pretrained(
model_args.tokenizer_name if model_args.tokenizer_name else model_args.model_name_or_path,
cache_dir=model_args.cache_dir,
)
model = AutoModelForSeq2SeqLM.from_pretrained(
model_args.model_name_or_path,
from_tf=".ckpt" in model_args.model_name_or_path,
config=config,
cache_dir=model_args.cache_dir,
)
# use task specific params
use_task_specific_params(model, data_args.task)
# set num_beams for evaluation
if data_args.eval_beams is not None:
model.config.num_beams = data_args.eval_beams
assert model.config.num_beams >= 1, f"got eval_beams={model.config.num_beams}. Need an integer >= 1"
# set max length for generation
model.config.max_generate_length = data_args.val_max_target_length
# set decoder_start_token_id for MBart
if model.config.decoder_start_token_id is None and isinstance(tokenizer, MBartTokenizer):
decoder_start_token_id = tokenizer.lang_code_to_id[data_args.tgt_lang]
model.config.decoder_start_token_id = decoder_start_token_id
def build_compute_metrics_fn(task_name: str) -> Callable[[EvalPrediction], Dict]:
def non_pad_len(tokens: np.ndarray) -> int:
return np.count_nonzero(tokens != tokenizer.pad_token_id)
def decode_pred(pred: EvalPrediction) -> Tuple[List[str], List[str]]:
pred_str = tokenizer.batch_decode(pred.predictions, skip_special_tokens=True)
label_str = tokenizer.batch_decode(pred.label_ids, skip_special_tokens=True)
pred_str = lmap(str.strip, pred_str)
label_str = lmap(str.strip, label_str)
return pred_str, label_str
def summarization_metrics(pred: EvalPrediction) -> Dict:
pred_str, label_str = decode_pred(pred)
rouge: Dict = calculate_rouge(pred_str, label_str)
summ_len = np.mean(lmap(non_pad_len, pred.predictions))
rouge.update({"gen_len": summ_len})
return rouge
def translation_metrics(pred: EvalPrediction) -> Dict:
pred_str, label_str = decode_pred(pred)
bleu: Dict = calculate_bleu(pred_str, label_str)
gen_len = np.mean(lmap(non_pad_len, pred.predictions))
bleu.update({"gen_len": gen_len})
return bleu
compute_metrics_fn = summarization_metrics if "summarization" in task_name else translation_metrics
return compute_metrics_fn
def freeze_embeds(model: torch.nn.Module):
"""Freeze token embeddings and positional embeddings for bart, just token embeddings for t5."""
try:
freeze_params(model.model.shared)
for d in [model.model.encoder, model.model.decoder]:
freeze_params(d.embed_positions)
freeze_params(d.embed_tokens)
except AttributeError:
freeze_params(model.shared)
for d in [model.encoder, model.decoder]:
freeze_params(d.embed_tokens)
if model_args.freeze_embeds:
freeze_embeds(model)
if model_args.freeze_encoder:
freeze_params(model.get_encoder())
assert_all_frozen(model.get_encoder())
dataset_class = Seq2SeqDataset if hasattr(tokenizer, "prepare_seq2seq_batch") else LegacySeq2SeqDataset
# Get datasets
train_dataset = (
dataset_class(
tokenizer,
type_path="train",
data_dir=data_args.data_dir,
n_obs=data_args.n_train,
max_target_length=data_args.max_target_length,
max_source_length=data_args.max_source_length,
prefix=model.config.prefix or "",
)
if training_args.do_train
else None
)
eval_dataset = (
dataset_class(
tokenizer,
type_path="val",
data_dir=data_args.data_dir,
n_obs=data_args.n_val,
max_target_length=data_args.val_max_target_length,
max_source_length=data_args.max_source_length,
prefix=model.config.prefix or "",
)
if training_args.do_eval
else None
)
test_dataset = (
dataset_class(
tokenizer,
type_path="test",
data_dir=data_args.data_dir,
n_obs=data_args.n_test,
max_target_length=data_args.test_max_target_length,
max_source_length=data_args.max_source_length,
prefix=model.config.prefix or "",
)
if training_args.do_predict
else None
)
# Initialize our Trainer
trainer = Seq2SeqTrainer(
model=model,
args=training_args,
train_dataset=train_dataset,
eval_dataset=eval_dataset,
data_collator=Seq2SeqDataCollator(tokenizer, data_args, training_args.tpu_num_cores),
compute_metrics=build_compute_metrics_fn(data_args.task) if training_args.predict_with_generate else None,
)
# Training
if training_args.do_train:
trainer.train(
model_path=model_args.model_name_or_path if os.path.isdir(model_args.model_name_or_path) else None
)
trainer.save_model()
# For convenience, we also re-save the tokenizer to the same directory,
# so that you can share your model easily on huggingface.co/models =)
if trainer.is_world_process_zero():
tokenizer.save_pretrained(training_args.output_dir)
# Evaluation
eval_results = {}
if training_args.do_eval:
logger.info("*** Evaluate ***")
result = trainer.evaluate()
output_eval_file = os.path.join(training_args.output_dir, "eval_results.json")
if trainer.is_world_process_zero():
logger.info("***** Eval results *****")
for key, value in result.items():
logger.info(" %s = %s", key, value)
with open(output_eval_file, "w") as f:
json.dump(result, f)
eval_results.update(result)
if training_args.do_predict:
logging.info("*** Test ***")
test_output = trainer.predict(test_dataset=test_dataset)
test_metrics = test_output.metrics
test_metrics = {k.replace("eval", "test"): v for k, v in test_metrics.items()}
output_test_file = os.path.join(training_args.output_dir, "test_results.json")
if trainer.is_world_process_zero():
logger.info("***** Test results *****")
for key, value in test_metrics.items():
logger.info(" %s = %s", key, value)
with open(output_test_file, "w") as f:
json.dump(test_metrics, f)
if training_args.predict_with_generate:
test_preds = tokenizer.batch_decode(test_output.predictions, skip_special_tokens=True)
test_preds = lmap(str.strip, test_preds)
output_test_pred_file = os.path.join(training_args.output_dir, "test_generations.txt")
with open(output_test_pred_file, "w") as f:
f.write("\n".join(test_preds))
return eval_results
def _mp_fn(index):
# For xla_spawn (TPUs)
main()
if __name__ == "__main__":
main()