diff --git a/train_cispo.py b/train_cispo.py new file mode 100644 index 0000000..6c0ebd6 --- /dev/null +++ b/train_cispo.py @@ -0,0 +1,343 @@ +import os +import sys + +__package__ = "trainer" +sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..'))) + +import argparse +import re +import gc +import warnings +import torch +import torch.distributed as dist +from transformers import AutoTokenizer +from contextlib import nullcontext +from torch import optim +from torch.nn.parallel import DistributedDataParallel +from torch.utils.data import DataLoader, DistributedSampler +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') + + +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): + 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 or match_pattern2: + format_rewards.append(0.5) + else: + format_rewards.append(0.0) + rewards += torch.tensor(format_rewards, device=args.device) + + 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) + if args.reasoning == 1: + rewards = reasoning_model_reward(rewards) + + with torch.no_grad(): + reward_model_scores = [] + batch_size = len(prompts) + scale = 3.0 + + for i in range(batch_size): + for j in range(args.num_generations): + response_idx = i * args.num_generations + j + response = responses[response_idx] + prompt = prompts[i] + + 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) + score = max(min(score, scale), -scale) + + if args.reasoning == 1: + answer_match = re.search(r'(.*?)', response, re.DOTALL) + if answer_match: + answer_content = answer_match.group(1).strip() + 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 get_per_token_logps(mdl, input_ids, n_keep): + """计算每个token的log概率""" + # CISPO 需要多次计算 logps,必须保留梯度 + if not mdl.training: + with torch.no_grad(): + logits = mdl(input_ids, logits_to_keep=n_keep + 1).logits[:, :-1, :] + else: + logits = mdl(input_ids, logits_to_keep=n_keep + 1).logits[:, :-1, :] + + per_token_logps = [] + for logits_row, ids_row in zip(logits, input_ids[:, -n_keep:]): + per_token_logps.append(torch.gather(logits_row.log_softmax(dim=-1), 1, ids_row.unsqueeze(1)).squeeze(1)) + return torch.stack(per_token_logps) + +def cispo_train_epoch(epoch, loader, iters, ref_model, reward_model, reward_tokenizer, start_step=0, wandb=None): + for step, batch in enumerate(loader, start=start_step + 1): + prompts = batch['prompt'] + prompt_inputs = tokenizer(prompts, return_tensors="pt", padding=True, return_token_type_ids=False, + padding_side="left", add_special_tokens=False).to(args.device) + + if args.max_seq_len: + prompt_inputs["input_ids"] = prompt_inputs["input_ids"][:, -args.max_seq_len:] + prompt_inputs["attention_mask"] = prompt_inputs["attention_mask"][:, -args.max_seq_len:] + + # ========== 1. 采样 (Sampling) ========== + with torch.no_grad(): + model_for_gen = model.module if isinstance(model, DistributedDataParallel) else model + outputs = model_for_gen.generate( + **prompt_inputs, max_new_tokens=args.max_gen_len, do_sample=True, temperature=0.8, + num_return_sequences=args.num_generations, pad_token_id=tokenizer.pad_token_id) + + completion_ids = outputs[:, prompt_inputs["input_ids"].size(1):] + + # ========== 2. 准备 Reference 和 Old Policy ========== + with torch.no_grad(): + # 计算参考模型的 logps (用于 KL 惩罚) + ref_per_token_logps = get_per_token_logps(ref_model, outputs, completion_ids.size(1)) + # 计算当前(旧)策略的 logps (用于计算 Ratio,在 Inner Loop 中保持不变) + old_per_token_logps = get_per_token_logps(model, outputs, completion_ids.size(1)) + + # ========== 3. 计算奖励 (Reward & Advantage) ========== + completions = tokenizer.batch_decode(completion_ids, skip_special_tokens=True) + rewards = calculate_rewards(prompts, completions, reward_model, reward_tokenizer).to(args.device) + + grouped_rewards = rewards.view(-1, args.num_generations) + mean_r = grouped_rewards.mean(dim=1).repeat_interleave(args.num_generations) + std_r = grouped_rewards.std(dim=1).repeat_interleave(args.num_generations) + + # 归一化优势 + advantages = torch.clamp((rewards - mean_r) / (std_r + 1e-4), -10, 10) + # 此处可以做全局归一化 + # advantages = (advantages - advantages.mean()) / (advantages.std() + 1e-8) + + # 准备 Mask + is_eos = completion_ids == tokenizer.eos_token_id + eos_idx = torch.full((is_eos.size(0),), is_eos.size(1), dtype=torch.long, device=args.device) + eos_idx[is_eos.any(dim=1)] = is_eos.int().argmax(dim=1)[is_eos.any(dim=1)] + completion_mask = (torch.arange(is_eos.size(1), device=args.device).expand(is_eos.size(0), -1) <= eos_idx.unsqueeze(1)).int() + + # ========== 4. CISPO Inner Loop (多步更新) ========== + # 循环多次,Ratio 才会发生变化,Clipping 才会生效 + for _ in range(args.ppo_epochs): + # 获取当前模型的 logps (带有梯度) + per_token_logps = get_per_token_logps(model, outputs, completion_ids.size(1)) + + # 计算 Ratio + # ratio = exp(curr - old) + ratio = torch.exp(per_token_logps - old_per_token_logps) + + + # 计算裁剪统计信息 (用于日志记录) + # 找到高于上限和低于下限的部分 + over_upper = (ratio > (1.0 + args.clip_ratio)).float() + under_lower = (ratio < (1.0 - args.clip_ratio)).float() + + # 计算总的被裁剪比例 (Token 级别) + clip_fraction = (over_upper + under_lower).mean().item() + + # 分别查看上溢和下溢(有助于分析模型是变激进了还是变保守了) + upper_fraction = over_upper.mean().item() + lower_fraction = under_lower.mean().item() + + + # --- CISPO 核心逻辑 --- + # 1. 计算裁剪后的权重系数 (Weight Clipping) + # 关键:必须 .detach(),使其变为常数系数,而不是目标函数的一部分 + clipped_ratio = torch.clamp(ratio, 1.0 - args.clip_ratio, 1.0 + args.clip_ratio).detach() + + # 2. 计算 KL 惩罚 (Token-level) + kl_div = ref_per_token_logps - per_token_logps + per_token_kl = torch.exp(kl_div) - kl_div - 1 + + # 3. 计算 Loss + # 公式: L = - (Clipped_Weight * log_pi * A) + beta * KL + # 这里利用 pytorch 的自动求导:nabla(log_pi) * A * Weight + cispo_loss = - (clipped_ratio * per_token_logps * advantages.unsqueeze(1)) + args.beta * per_token_kl + # --- CISPO 核心逻辑 End --- + + # Mask 和 聚合 + loss = ((cispo_loss * completion_mask).sum(dim=1) / completion_mask.sum(dim=1)).mean() / args.accumulation_steps + + loss.backward() + + if (step + 1) % args.accumulation_steps == 0: + if args.grad_clip > 0: + torch.nn.utils.clip_grad_norm_(model.parameters(), args.grad_clip) + optimizer.step() + scheduler.step() + optimizer.zero_grad() + torch.cuda.empty_cache() + + if step % args.log_interval == 0 or step == iters: + # 记录日志 + policy_loss_val = loss.item() * args.accumulation_steps + avg_reward_val = rewards.mean().item() + avg_len_val = completion_mask.sum(dim=1).float().mean().item() + current_lr = optimizer.param_groups[0]['lr'] + + Logger(f'Epoch: {epoch+1}, Step: {step}/{iters}, ' + f'CISPO Loss: {policy_loss_val:.6f}, Reward: {avg_reward_val:.6f}, ' + f'Avg Response Len: {avg_len_val:.2f}, LR: {current_lr:.2e}') + + if wandb and is_main_process(): + wandb.log({ + "policy_loss": policy_loss_val, + "reward": avg_reward_val, + "avg_response_len": avg_len_val, + "advantages_mean": advantages.mean().item(), + "learning_rate": current_lr, + "ratio": ratio.mean().item(), + "cispo/clip_fraction": clip_fraction, # 总裁剪率 + "cispo/upper_clip_fraction": upper_fraction, # 上裁剪率(由于当前动作概率大幅增加导致) + "cispo/lower_clip_fraction": lower_fraction, # 下裁剪率(由于当前动作概率大幅降低导致) + }) + + # 保存模型的代码保持不变 + if (step % args.save_interval == 0 or step == iters - 1) and is_main_process(): + 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' + state_dict = model.module.state_dict() if isinstance(model, DistributedDataParallel) else model.state_dict() + torch.save({k: v.half().cpu() for k, v in state_dict.items()}, ckp) + lm_checkpoint(lm_config, weight=args.save_weight, model=model, optimizer=optimizer, + epoch=epoch, step=step, wandb=wandb, save_dir='../checkpoints', scheduler=scheduler) + model.train() + del state_dict + + del prompt_inputs, outputs, completion_ids, per_token_logps, ref_per_token_logps, old_per_token_logps + del completions, rewards, grouped_rewards, mean_r, std_r, advantages, completion_mask + torch.cuda.empty_cache() + gc.collect() + + +if __name__ == "__main__": + parser = argparse.ArgumentParser(description="MiniMind CISPO (Clipped Importance Sampling Policy Optimization)") + # 原有参数保持不变 + parser.add_argument("--save_dir", type=str, default="../out", help="模型保存目录") + parser.add_argument('--save_weight', default='cispo', 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="初始学习率") + 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("--num_generations", type=int, default=8, help="每个prompt生成的样本数") + parser.add_argument("--beta", type=float, default=0.02, help="KL惩罚系数") + parser.add_argument("--reasoning", type=int, default=1, choices=[0, 1], help='推理模型类型') + 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") + parser.add_argument("--use_wandb", action="store_true", help="是否使用wandb") + parser.add_argument("--wandb_project", type=str, default="MiniMind-CISPO", help="wandb项目名") + + # === CISPO 新增参数 === + parser.add_argument("--clip_ratio", type=float, default=0.2, help="CISPO/PPO 裁剪系数") + parser.add_argument("--ppo_epochs", type=int, default=1, help="每个Batch的更新次数 (Inner Loop)") + + args = parser.parse_args() + + # 后续初始化代码与原 GRPO 代码一致,只需将 train_epoch 调用替换为 cispo_train_epoch + # ========== 1. 初始化环境 ========== + 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)) + + os.makedirs(args.save_dir, exist_ok=True) + lm_config = MiniMindConfig(hidden_size=args.hidden_size, num_hidden_layers=args.num_hidden_layers, + max_seq_len=args.max_seq_len + args.max_gen_len, 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 + + 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) + + 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-CISPO-Epoch-{args.epochs}" + wandb.init(project=args.wandb_project, name=wandb_run_name, id=wandb_id, resume=resume, mode="local") + + base_weight = "reason" if args.reasoning == 1 else "full_sft" + model, tokenizer = init_model(lm_config, base_weight, device=args.device) + ref_model, _ = init_model(lm_config, base_weight, device=args.device) + ref_model = ref_model.eval().requires_grad_(False) + + 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) + + train_ds = RLAIFDataset(args.data_path, tokenizer, max_length=lm_config.max_seq_len) + train_sampler = DistributedSampler(train_ds) if dist.is_initialized() else None + optimizer = optim.AdamW(model.parameters(), lr=args.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 * args.ppo_epochs # 注意这里total steps变了 + scheduler = CosineAnnealingLR(optimizer, T_max=total_optimizer_steps, eta_min=args.learning_rate / 10) + + start_epoch, start_step = 0, 0 + if ckp_data: + model.load_state_dict(ckp_data['model']) + optimizer.load_state_dict(ckp_data['optimizer']) + scheduler.load_state_dict(ckp_data['scheduler']) + start_epoch = ckp_data['epoch'] + start_step = ckp_data.get('step', 0) + + if dist.is_initialized(): + model._ddp_params_and_buffers_to_ignore = {"freqs_cos", "freqs_sin"} + model = DistributedDataParallel(model, device_ids=[local_rank]) + + for epoch in range(start_epoch, args.epochs): + train_sampler and train_sampler.set_epoch(epoch) + if epoch == start_epoch and start_step > 0: + 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) + cispo_train_epoch(epoch, loader, len(loader) + start_step + 1, ref_model, reward_model, reward_tokenizer, start_step, wandb) + else: + loader = DataLoader(train_ds, batch_size=args.batch_size, pin_memory=True, drop_last=False, shuffle=(train_sampler is None), num_workers=args.num_workers, sampler=train_sampler) + cispo_train_epoch(epoch, loader, len(loader), ref_model, reward_model, reward_tokenizer, 0, wandb)