text
stringlengths
1
93.6k
start_epoch = training_state['epoch']
total_steps_count = training_state['step']
best_reward = training_state['reward']
logger.info(f"Resuming from epoch {start_epoch}, step {total_steps_count}")
else:
start_epoch = 0
total_steps_count = 0
best_reward = float('-inf')
model, optimizer, dataloader, lr_scheduler, ref_model = accelerator.prepare(
model, optimizer, dataloader, lr_scheduler, ref_model)
trainer = GRPOTrainer(
config=config,
model=model,
ref_model=ref_model,
tokenizer=tokenizer,
optimizer=optimizer,
lr_scheduler=lr_scheduler,
accelerator=accelerator,
)
# define reward funcs
perplexity_reward_func = partial(perplexity_reward, model=ref_model, tokenizer=tokenizer)
perplexity_reward_func.__name__ = "perplexity_reward"
reward_funcs = [
perplexity_reward_func,
llm_rater_reward,
repetition_reward,
length_reward,
chinese_char_ratio_reward
]
max_train_steps = num_epochs * len(dataloader)
progress_bar = tqdm(range(max_train_steps), desc="Training Steps", disable=not accelerator.is_local_main_process)
progress_bar.update(total_steps_count) # 更新进度条到恢复的步数
for epoch in range(start_epoch, num_epochs):
metrics = {}
for step, batch in enumerate(dataloader):
prompts = batch["prompt"]
prompt_ids = tokenizer(prompts, return_tensors="pt", add_special_tokens=True, padding=True)["input_ids"].to(accelerator.device)
prompt_len = prompt_ids.shape[1]
# reject sampling
gen_config = {
"max_new_tokens": 512,
"temperature": 0.7,
"top_p": 0.9,
"top_k": 50,
"repetition_penalty": 1.1,
"do_sample": True,
"pad_token_id": tokenizer.pad_token_id,
"eos_token_id": tokenizer.eos_token_id,
"use_cache": True,
"num_beams": 1,
"num_return_sequences": group_num,
}
completions = trainer.generate(
prompt_ids,
**gen_config
)
torch.cuda.empty_cache()
completion_ids = completions[:, prompt_len:]
completion_texts = tokenizer.batch_decode(completion_ids, skip_special_tokens=True) # group_num * batch_size
# get reward kwargs
reward_kwargs = {key: [] for key in batch.keys() if key not in ["prompt", "completions"]}
for key in reward_kwargs:
for example in batch[key]:
# Repeat each value in the column for `num_generations` times
reward_kwargs[key].extend([example] * config.group_num)
# call reward funcs
all_rewards = []
for reward_func in reward_funcs:
rewards = np.array(reward_func(completion_texts, **reward_kwargs)) # length: group_num * batch_size
all_rewards.append(rewards) # length: func_num
all_rewards = np.array(all_rewards) # func_num, group_num * batch_size
reward_per_func = all_rewards.mean(axis=1) # func_num
reward_all_funcs = all_rewards.sum(axis=0) # group_num * batch_size
for i, reward_func in enumerate(reward_funcs):
reward_func_name = reward_func.__name__
metrics[f"rewards/{reward_func_name}"] = reward_per_func[i].item()
# expand prompt_ids, align with length of completions
prompt_ids = prompt_ids.unsqueeze(1).expand(-1, config.group_num, -1).reshape(-1, prompt_ids.size(-1))
reward_all_funcs = torch.tensor(reward_all_funcs, device=accelerator.device)
# grpo step
trainer.step(
prompt_ids=prompt_ids,
completion_ids=completion_ids,
reward_scores=reward_all_funcs
)
total_steps_count += 1
current_lr = lr_scheduler.get_last_lr()[0]
avg_reward_score = reward_all_funcs.mean().item()