diff --git a/train_gated_ppo.py b/train_gated_ppo.py new file mode 100644 index 0000000..6aa966b --- /dev/null +++ b/train_gated_ppo.py @@ -0,0 +1,372 @@ +import os +import sys + +__package__ = "trainer" +sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..'))) + +import argparse +import re +import warnings +import torch +import torch.distributed as dist +import torch.nn.functional as F +from transformers import AutoTokenizer +from contextlib import nullcontext +from torch import optim, nn +from torch.nn.parallel import DistributedDataParallel +from torch.utils.data import DataLoader, DistributedSampler +from torch.nn.utils import clip_grad_norm_ +from torch.optim.lr_scheduler import CosineAnnealingLR +from transformers import AutoModel +from model.model_minimind import MiniMindConfig, MiniMindForCausalLM +from dataset.lm_dataset import RLAIFDataset +from trainer.trainer_utils import Logger, is_main_process, lm_checkpoint, init_distributed_mode, setup_seed, SkipBatchSampler, init_model + +warnings.filterwarnings('ignore') + + +# 自定义的Critic模型,继承自MiniMindLM +class CriticModel(MiniMindForCausalLM): + def __init__(self, params): + super().__init__(params) + # 替换lm_head为输出单一价值的线性层 + self.value_head = nn.Linear(params.hidden_size, 1) + + def forward(self, input_ids=None, attention_mask=None, **kwargs): + # 使用基础模型获取隐藏状态 + outputs = self.model(input_ids=input_ids, attention_mask=attention_mask, **kwargs) + hidden_states = self.model.norm(outputs[0]) + # 使用value_head获取价值估计 + values = self.value_head(hidden_states).squeeze(-1) + return values + + +def calculate_rewards(prompts, responses, reward_model, reward_tokenizer): + """整合所有奖励函数计算总奖励""" + def reasoning_model_reward(rewards): + # 1. 格式奖励(仅针对训练推理模型时使用) + pattern = r"^\n.*?\n\n\n.*?\n$" + pattern2 = r"^\n.*?\n\n\n\n.*?\n$" + + matches_pattern = [re.match(pattern, response, re.S) for response in responses] + matches_pattern2 = [re.match(pattern2, response, re.S) for response in responses] + + format_rewards = [] + for match_pattern, match_pattern2 in zip(matches_pattern, matches_pattern2): + if match_pattern: + format_rewards.append(0.5) + elif match_pattern2: + format_rewards.append(0.5) + else: + format_rewards.append(0.0) + rewards += torch.tensor(format_rewards, device=args.device) + + # 2. 标记奖励(防止严格奖励稀疏,仅针对训练推理模型时使用) + def mark_num(text): + reward = 0 + if text.count("") == 1: + reward += 0.25 + if text.count("") == 1: + reward += 0.25 + if text.count("") == 1: + reward += 0.25 + if text.count("") == 1: + reward += 0.25 + return reward + + mark_rewards = [mark_num(response) for response in responses] + rewards += torch.tensor(mark_rewards, device=args.device) + return rewards + + rewards = torch.zeros(len(responses), device=args.device) + + # 格式奖励 + if args.reasoning == 1: + rewards = reasoning_model_reward(rewards) + + # 使用reward model计算整个response的奖励 + with torch.no_grad(): + reward_model_scores = [] + for prompt, response in zip(prompts, responses): + pattern = r"<\|im_start\|>(system|user|assistant)\s+(.*?)<\|im_end\|>" + matches = re.findall(pattern, prompt, re.DOTALL) + messages = [{"role": role, "content": content.strip()} for role, content in matches] + + tmp_chat = messages + [{"role": "assistant", "content": response}] + score = reward_model.get_score(reward_tokenizer, tmp_chat) + + scale = 3.0 + score = max(min(score, scale), -scale) + + # 当args.reasoning=1时,额外计算内容的奖励 + if args.reasoning == 1: + answer_match = re.search(r'(.*?)', response, re.DOTALL) + if answer_match: + answer_content = answer_match.group(1).strip() + # 对answer内容单独计算reward + tmp_chat = messages + [{"role": "assistant", "content": answer_content}] + answer_score = reward_model.get_score(reward_tokenizer, tmp_chat) + answer_score = max(min(answer_score, scale), -scale) + score = score * 0.4 + answer_score * 0.6 + reward_model_scores.append(score) + + reward_model_scores = torch.tensor(reward_model_scores, device=args.device) + rewards += reward_model_scores + + return rewards + + +def ppo_train_epoch(epoch, loader, iters, old_actor_model, ref_model, actor_scheduler, critic_scheduler, reward_model, reward_tokenizer, start_step=0, wandb=None): + actor_model.train() + critic_model.train() + + for step, batch in enumerate(loader, start=start_step + 1): + prompts = batch["prompt"] # list[str], length B + enc = tokenizer(prompts, return_tensors="pt", padding=True, truncation=True, + max_length=args.max_seq_len).to(args.device) # input_ids: [B, P], attention_mask: [B, P] + prompt_lengths = torch.full((enc.input_ids.size(0),), enc.input_ids.shape[1], dtype=torch.long, device=enc.input_ids.device) # [B] + + with torch.no_grad(): + # DDP 模型需要使用 .module 访问 generate 方法 + model_for_gen = actor_model.module if isinstance(actor_model, DistributedDataParallel) else actor_model + gen_out = model_for_gen.generate( + input_ids=enc.input_ids, attention_mask=enc.attention_mask, + max_new_tokens=args.max_gen_len, do_sample=True, temperature=0.8, + pad_token_id=tokenizer.pad_token_id, eos_token_id=tokenizer.eos_token_id) # [B, P+R] + + responses_text = [tokenizer.decode(gen_out[i, prompt_lengths[i]:], skip_special_tokens=True) for i in range(len(prompts))] + rewards = calculate_rewards(prompts, responses_text, reward_model, reward_tokenizer) # [B] + + full_mask = (gen_out != tokenizer.pad_token_id).long() # [B, P+R] + values_seq = critic_model(input_ids=gen_out, attention_mask=full_mask) # [B, P+R] + last_indices = (full_mask * torch.arange(full_mask.size(1), device=gen_out.device)).argmax(dim=1) + values = values_seq[torch.arange(values_seq.size(0), device=values_seq.device), last_indices] # [B] + advantages = rewards - values.detach() # [B] + + logits = actor_model(input_ids=gen_out, attention_mask=full_mask).logits # [B, P+R, V] + labels = gen_out[:, 1:].clone() # [B, P+R-1] + logp_tokens = F.log_softmax(logits[:, :-1], dim=-1).gather(2, labels.unsqueeze(-1)).squeeze(-1) # [B, P+R-1] + seq_len = gen_out.size(1) - 1 + resp_mask = torch.arange(seq_len, device=gen_out.device).unsqueeze(0) >= prompt_lengths.unsqueeze(1) + final_mask = resp_mask & (~labels.eq(tokenizer.pad_token_id)) # [B, P+R-1] + actor_logp = (logp_tokens * final_mask).sum(dim=1) # [B] + + with torch.no_grad(): + old_logits = old_actor_model(input_ids=gen_out, attention_mask=full_mask).logits # [B, P+R, V] + old_logp_tokens = F.log_softmax(old_logits[:, :-1], dim=-1).gather(2, labels.unsqueeze(-1)).squeeze(-1) # [B, P+R-1] + old_logp = (old_logp_tokens * final_mask).sum(dim=1) # [B] + + ref_logits = ref_model(input_ids=gen_out, attention_mask=full_mask).logits # [B, P+R, V] + ref_logp_tokens = F.log_softmax(ref_logits[:, :-1], dim=-1).gather(2, labels.unsqueeze(-1)).squeeze(-1) # [B, P+R-1] + ref_logp = (ref_logp_tokens * final_mask).sum(dim=1) # [B] + + kl = (actor_logp - old_logp).mean() # scalar + kl_ref = (actor_logp - ref_logp).mean() # scalar + + + # 修改部分:添加门控 + ratio = torch.exp(actor_logp - old_logp) # [B] + ratio = ratio * torch.sigmoid(0.5 * ratio) + + surr1 = ratio * advantages # [B] + surr2 = torch.clamp(ratio, 1.0 - args.clip_epsilon, 1.0 + args.clip_epsilon) * advantages # [B] + policy_loss = -torch.min(surr1, surr2).mean() # scalar + value_loss = F.mse_loss(values, rewards) # scalar + loss = policy_loss + args.vf_coef * value_loss + args.kl_coef * kl_ref # scalar + loss.backward() + + if (step + 1) % args.accumulation_steps == 0: + clip_grad_norm_(actor_model.parameters(), args.grad_clip) + clip_grad_norm_(critic_model.parameters(), args.grad_clip) + actor_optimizer.step() + critic_optimizer.step() + actor_scheduler.step() + critic_scheduler.step() + actor_optimizer.zero_grad() + critic_optimizer.zero_grad() + torch.cuda.empty_cache() + + if is_main_process(): + response_ids = gen_out[:, enc.input_ids.shape[1]:] + is_eos = (response_ids == tokenizer.eos_token_id) + eos_indices = torch.argmax(is_eos.int(), dim=1) + has_eos = is_eos.any(dim=1) + lengths = torch.where(has_eos, eos_indices + 1, torch.tensor(response_ids.shape[1], device=is_eos.device)) + avg_len = lengths.float().mean() + + actor_loss_val = policy_loss.item() + critic_loss_val = value_loss.item() + reward_val = rewards.mean().item() + kl_val = kl.item() + kl_ref_val = kl_ref.item() + avg_len_val = avg_len.item() + actor_lr = actor_optimizer.param_groups[0]['lr'] + critic_lr = critic_optimizer.param_groups[0]['lr'] + + if wandb is not None: + wandb.log({ + "actor_loss": actor_loss_val, + "critic_loss": critic_loss_val, + "reward": reward_val, + "kl": kl_val, + "kl_ref": kl_ref_val, + "avg_response_len": avg_len_val, + "actor_lr": actor_lr, + }) + + Logger(f"Epoch: {epoch+1}, Step: {step}/{iters}, " + f"Actor Loss: {actor_loss_val:.6f}, Critic Loss: {critic_loss_val:.6f}, " + f"Reward: {reward_val:.6f}, KL: {kl_val:.6f}, KL_ref: {kl_ref_val:.6f}, " + f"Avg Response Len: {avg_len_val:.2f}, Actor LR: {actor_lr:.2e}, Critic LR: {critic_lr:.2e}") + + if (step + 1) % args.update_old_actor_freq == 0: + state_dict = actor_model.module.state_dict() if isinstance(actor_model, DistributedDataParallel) else actor_model.state_dict() + old_actor_model.load_state_dict({k: v.detach().cpu() for k, v in state_dict.items()}) + old_actor_model.to(args.device) + + if (step % args.save_interval == 0 or step == iters - 1) and is_main_process(): + actor_model.eval() + moe_suffix = '_moe' if lm_config.use_moe else '' + ckp = f'{args.save_dir}/{args.save_weight}_{lm_config.hidden_size}{moe_suffix}.pth' + actor_state = actor_model.module.state_dict() if isinstance(actor_model, DistributedDataParallel) else actor_model.state_dict() + torch.save({k: v.half().cpu() for k, v in actor_state.items()}, ckp) + + # 使用 lm_checkpoint 保存完整状态(包括 critic) + lm_checkpoint(lm_config, weight=args.save_weight, model=actor_model, optimizer=actor_optimizer, + epoch=epoch, step=step, wandb=wandb, save_dir='../checkpoints', + scheduler=actor_scheduler, critic_model=critic_model, + critic_optimizer=critic_optimizer, critic_scheduler=critic_scheduler) + actor_model.train() + del actor_state + + del enc, gen_out, responses_text, rewards, full_mask, values_seq, values, advantages + del logits, labels, logp_tokens, final_mask, actor_logp, old_logits, old_logp, ref_logits, ref_logp + del kl, kl_ref, ratio, surr1, surr2, policy_loss, value_loss, loss + torch.cuda.empty_cache() + + +if __name__ == "__main__": + parser = argparse.ArgumentParser(description="MiniMind PPO (Proximal Policy Optimization)") + parser.add_argument("--save_dir", type=str, default="../out", help="模型保存目录") + parser.add_argument('--save_weight', default='ppo_actor', type=str, help="保存权重的前缀名") + parser.add_argument("--epochs", type=int, default=1, help="训练轮数") + parser.add_argument("--batch_size", type=int, default=2, help="batch size") + parser.add_argument("--learning_rate", type=float, default=8e-8, help="Actor学习率") + parser.add_argument("--critic_learning_rate", type=float, default=8e-8, help="Critic学习率") + parser.add_argument("--device", type=str, default="cuda:0" if torch.cuda.is_available() else "cpu", help="训练设备") + parser.add_argument("--dtype", type=str, default="bfloat16", help="混合精度类型") + parser.add_argument("--num_workers", type=int, default=1, help="数据加载线程数") + parser.add_argument("--accumulation_steps", type=int, default=1, help="梯度累积步数") + parser.add_argument("--grad_clip", type=float, default=1.0, help="梯度裁剪阈值") + parser.add_argument("--log_interval", type=int, default=1, help="日志打印间隔") + parser.add_argument("--save_interval", type=int, default=10, help="模型保存间隔") + parser.add_argument('--hidden_size', default=512, type=int, help="隐藏层维度") + parser.add_argument('--num_hidden_layers', default=8, type=int, help="隐藏层数量") + parser.add_argument('--use_moe', default=0, type=int, choices=[0, 1], help="是否使用MoE架构(0=否,1=是)") + parser.add_argument('--max_seq_len', default=66, type=int, help="Prompt最大长度") + parser.add_argument("--max_gen_len", type=int, default=1536, help="生成的最大长度") + parser.add_argument("--data_path", type=str, default="../dataset/rlaif-mini.jsonl", help="RLAIF数据路径") + parser.add_argument("--clip_epsilon", type=float, default=0.1, help="PPO裁剪参数") + parser.add_argument("--vf_coef", type=float, default=0.5, help="Value function系数") + parser.add_argument("--kl_coef", type=float, default=0.02, help="KL散度惩罚系数") + parser.add_argument("--reasoning", type=int, default=1, choices=[0, 1], help='推理模型类型(0=普通模型,1=推理模型)') + parser.add_argument("--update_old_actor_freq", type=int, default=4, help="更新old_actor_model的频率") + parser.add_argument("--reward_model_path", type=str, default="../../internlm2-1_8b-reward", help="Reward模型路径") + parser.add_argument('--from_resume', default=0, type=int, choices=[0, 1], help="是否自动检测&续训(0=否,1=是)") + parser.add_argument("--use_wandb", action="store_true", help="是否使用wandb") + parser.add_argument("--wandb_project", type=str, default="MiniMind-gated_PPO", help="wandb项目名") + args = parser.parse_args() + + # ========== 1. 初始化环境和随机种子 ========== + local_rank = init_distributed_mode() + if dist.is_initialized(): args.device = f"cuda:{local_rank}" + setup_seed(42 + (dist.get_rank() if dist.is_initialized() else 0)) + + # ========== 2. 配置目录、模型参数、检查ckp ========== + os.makedirs(args.save_dir, exist_ok=True) + lm_config = MiniMindConfig(hidden_size=args.hidden_size, num_hidden_layers=args.num_hidden_layers, use_moe=bool(args.use_moe)) + ckp_data = lm_checkpoint(lm_config, weight=args.save_weight, save_dir='../checkpoints') if args.from_resume==1 else None + + # ========== 3. 设置混合精度 ========== + device_type = "cuda" if "cuda" in args.device else "cpu" + dtype = torch.bfloat16 if args.dtype == "bfloat16" else torch.float16 + autocast_ctx = nullcontext() if device_type == "cpu" else torch.cuda.amp.autocast(dtype=dtype) + + # ========== 4. 配wandb ========== + wandb = None + if args.use_wandb and is_main_process(): + import swanlab as wandb + wandb_id = ckp_data.get('wandb_id') if ckp_data else None + resume = 'must' if wandb_id else None + wandb_run_name = f"MiniMind-gated_PPO-Epoch-{args.epochs}-BS-{args.batch_size}-LR-{args.learning_rate}" + wandb.init(project=args.wandb_project, name=wandb_run_name, id=wandb_id, resume=resume, mode="local") + + # ========== 5. 初始化模型和数据 ========== + base_weight = "reason" if args.reasoning == 1 else "full_sft" + # Actor模型 + actor_model, tokenizer = init_model(lm_config, base_weight, device=args.device) + tokenizer.padding_side = 'left' # PPO需要左侧padding + # Old Actor模型 + old_actor_model, _ = init_model(lm_config, base_weight, device=args.device) + old_actor_model = old_actor_model.eval().requires_grad_(False) + # Reference模型 + ref_model, _ = init_model(lm_config, base_weight, device=args.device) + ref_model = ref_model.eval().requires_grad_(False) + # Critic模型 + moe_suffix = '_moe' if lm_config.use_moe else '' + ckp = f'{args.save_dir}/{base_weight}_{lm_config.hidden_size}{moe_suffix}.pth' + state_dict = torch.load(ckp, map_location=args.device) + critic_model = CriticModel(lm_config) + critic_model.load_state_dict(state_dict, strict=False) + critic_model = critic_model.to(args.device) + # Reward模型 + reward_model = AutoModel.from_pretrained( + args.reward_model_path, torch_dtype=torch.float16, trust_remote_code=True + ) + reward_model = reward_model.to(args.device).eval().requires_grad_(False) + reward_tokenizer = AutoTokenizer.from_pretrained(args.reward_model_path, trust_remote_code=True) + # 数据和优化器 + train_ds = RLAIFDataset(args.data_path, tokenizer, max_length=(args.max_seq_len + args.max_gen_len)) + train_sampler = DistributedSampler(train_ds) if dist.is_initialized() else None + actor_optimizer = optim.AdamW(actor_model.parameters(), lr=args.learning_rate) + critic_optimizer = optim.AdamW(critic_model.parameters(), lr=args.critic_learning_rate) + loader_for_count = DataLoader(train_ds, batch_size=args.batch_size, sampler=train_sampler) + iters = len(loader_for_count) + total_optimizer_steps = (iters // args.accumulation_steps) * args.epochs + actor_scheduler = CosineAnnealingLR(actor_optimizer, T_max=total_optimizer_steps, eta_min=args.learning_rate / 10) + critic_scheduler = CosineAnnealingLR(critic_optimizer, T_max=total_optimizer_steps, eta_min=args.critic_learning_rate / 10) + + # ========== 6. 从ckp恢复状态 ========== + start_epoch, start_step = 0, 0 + if ckp_data: + actor_model.load_state_dict(ckp_data['model']) + critic_model.load_state_dict(ckp_data['critic_model']) + actor_optimizer.load_state_dict(ckp_data['optimizer']) + critic_optimizer.load_state_dict(ckp_data['critic_optimizer']) + actor_scheduler.load_state_dict(ckp_data['scheduler']) + critic_scheduler.load_state_dict(ckp_data['critic_scheduler']) + start_epoch = ckp_data['epoch'] + start_step = ckp_data.get('step', 0) + + # ========== 7. DDP包模型 ========== + if dist.is_initialized(): + actor_model._ddp_params_and_buffers_to_ignore = {"freqs_cos", "freqs_sin"} + critic_model._ddp_params_and_buffers_to_ignore = {"freqs_cos", "freqs_sin"} + actor_model = DistributedDataParallel(actor_model, device_ids=[local_rank]) + critic_model = DistributedDataParallel(critic_model, device_ids=[local_rank]) + old_actor_model.to(args.device) + + # ========== 8. 开始训练 ========== + for epoch in range(start_epoch, args.epochs): + train_sampler and train_sampler.set_epoch(epoch) + if epoch == start_epoch and start_step > 0: # 第一个epoch且存在检查点 + batch_sampler = SkipBatchSampler(train_sampler or range(len(train_ds)), args.batch_size, start_step + 1) + loader = DataLoader(train_ds, batch_sampler=batch_sampler, num_workers=args.num_workers, pin_memory=True) + Logger(f'Epoch [{epoch + 1}/{args.epochs}]: 跳过前{start_step}个step,从step {start_step + 1}开始') + ppo_train_epoch(epoch, loader, len(loader) + start_step + 1, old_actor_model, ref_model, + actor_scheduler, critic_scheduler, reward_model, reward_tokenizer, start_step, wandb) + else: # 默认从头开始 + loader = DataLoader(train_ds, batch_size=args.batch_size, shuffle=(train_sampler is None), + sampler=train_sampler, num_workers=args.num_workers, pin_memory=True) + ppo_train_epoch(epoch, loader, len(loader), old_actor_model, ref_model, + actor_scheduler, critic_scheduler, reward_model, reward_tokenizer, 0, wandb)