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| import pandas as pd
import torch
from datasets import load_dataset
from tqdm import tqdm
from transformers import AutoTokenizer, set_seed, pipeline
from trl import AutoModelForCausalLMWithValueHead, create_reference_model, PPOConfig, PPOTrainer
from trl.core import LengthSampler
model_name = "Wenzhong-GPT2-110M"
config = PPOConfig(
model_name=model_name,
learning_rate=1.41e-5,
log_with="tensorboard",
batch_size=64,
gradient_accumulation_steps=8,
mini_batch_size=8,
)
sent_kwargs = {"return_all_scores": True, "function_to_apply": "none", "batch_size": 16}
gpt2_tokenizer = AutoTokenizer.from_pretrained(config.model_name)
gpt2_tokenizer.pad_token = gpt2_tokenizer.eos_token
set_seed(1)
def build_dataset(input_min_text_length=2, input_max_text_length=8):
ds = load_dataset(
'csv',
data_files={
"train": "train.tsv",
"dev": "dev.tsv",
},
delimiter='\t'
)['train']
ds = ds.rename_columns({"text_a": "review"})
ds = ds.filter(lambda x: len(x['review']) > 10, batched=False)
input_size = LengthSampler(input_min_text_length, input_max_text_length)
def tokenize(sample):
sample["input_ids"] = gpt2_tokenizer.encode(sample["review"][: input_size()])
sample["query"] = gpt2_tokenizer.decode(sample["input_ids"])
return sample
ds = ds.map(tokenize, batched=False)
ds.set_format(type="torch")
return ds
dataset = build_dataset()
def collator(data):
return dict((key, [d[key] for d in data]) for key in data[0])
sentiment_pipe = pipeline(
"sentiment-analysis",
model='/score_model/checkpoint-1000',
device='cuda:1'
)
text = "今天天气很好"
print(sentiment_pipe(text, **sent_kwargs))
text = '这个电影主角演的真心一般般'
print(sentiment_pipe(text, **sent_kwargs))
output_min_length = 16
output_max_length = 32
output_length_sampler = LengthSampler(output_min_length, output_max_length)
model = AutoModelForCausalLMWithValueHead.from_pretrained(config.model_name)
ref_model = create_reference_model(model)
ppo_trainer = PPOTrainer(config, model, ref_model, gpt2_tokenizer, dataset, data_collator=collator)
generation_kwargs = {
"min_length": -1,
"top_k": 0,
"top_p": 1,
"do_sample": True,
"pad_token_id": gpt2_tokenizer.eos_token_id,
"bos_token_id": gpt2_tokenizer.bos_token_id,
"eos_token_id": gpt2_tokenizer.eos_token_id,
}
device = 'cuda:0'
for i in range(3):
for epoch, batch in tqdm(enumerate(ppo_trainer.dataloader)):
query_tensors = batch['input_ids']
response_tensors = []
for query in query_tensors:
gen_len = output_length_sampler()
response = ppo_trainer.generate(query, **{**generation_kwargs, "max_new_tokens": gen_len})
response_tensors.append(response.squeeze()[-gen_len:])
batch["response"] = [gpt2_tokenizer.decode(r.squeeze()) for r in response_tensors]
texts = [q + r for q, r in zip(batch["query"], batch["response"])]
pipe_outputs = sentiment_pipe(texts, **sent_kwargs)
rewards = [torch.tensor(output[1]["score"]) for output in pipe_outputs]
stats = ppo_trainer.step(query_tensors, response_tensors, rewards)
ppo_trainer.log_stats(stats, batch, rewards)
bs = 16
game_data = dict()
dataset.set_format("pandas")
df_batch = dataset[:].sample(bs)
game_data["query"] = df_batch["query"].tolist()
query_tensors = df_batch["input_ids"].tolist()
response_tensors_ref, response_tensors = [], []
for i in range(bs):
gen_len = output_length_sampler()
output = ref_model.generate(
torch.tensor(query_tensors[i]).unsqueeze(dim=0).to(device), max_new_tokens=gen_len, **generation_kwargs
).squeeze()[-gen_len:]
response_tensors_ref.append(output)
output = model.generate(
torch.tensor(query_tensors[i]).unsqueeze(dim=0).to(device), max_new_tokens=gen_len, **generation_kwargs
).squeeze()[-gen_len:]
response_tensors.append(output)
game_data["response (before)"] = [gpt2_tokenizer.decode(response_tensors_ref[i]) for i in range(bs)]
game_data["response (after)"] = [gpt2_tokenizer.decode(response_tensors[i]) for i in range(bs)]
texts = [q + r for q, r in zip(game_data["query"], game_data["response (before)"])]
game_data["rewards (before)"] = [output[1]["score"] for output in sentiment_pipe(texts, **sent_kwargs)]
texts = [q + r for q, r in zip(game_data["query"], game_data["response (after)"])]
game_data["rewards (after)"] = [output[1]["score"] for output in sentiment_pipe(texts, **sent_kwargs)]
df_results = pd.DataFrame(game_data)
print(df_results)
print("mean:")
print(df_results[["rewards (before)", "rewards (after)"]].mean())
print()
print("median:")
print(df_results[["rewards (before)", "rewards (after)"]].median())
model.save_pretrained("gpt2-imdb-pos-v2", push_to_hub=False)
gpt2_tokenizer.save_pretrained("gpt2-imdb-pos-v2", push_to_hub=False)
|
