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【Hackathon 10th Spring No.6】CrystalLLM 模型复现#255

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【Hackathon 10th Spring No.6】CrystalLLM 模型复现#255
cloudforge1 wants to merge 9 commits intoPaddlePaddle:developfrom
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@cloudforge1 cloudforge1 commented Mar 24, 2026

概述

实现 CrystalLLM 模型复现,基于论文 Crystal Structure Generation with Autoregressive Large Language Modeling (Antunes et al., Nature Communications, 2024),参考实现 lantunes/CrystaLLM(MIT License)。

CrystalLLM 使用 GPT-2 风格的自回归 Transformer 模型,以 CIF (Crystallographic Information File) 文本为序列,直接生成晶体结构。模型在 230 万结构(MP + OQMD + NOMAD)上训练,支持 Perov-5、MP-20、Carbon-24、MPTS-52 四个标准基准数据集。

新增内容

模型 (ppmat/models/crystalllm/)

  • CrystalLLM: GPT-2 风格 Transformer,支持 Small (8层/8头/512维) 和 Large (16层/16头/1024维) 配置
  • CIFTokenizer: 自定义 CIF 分词器,vocab_size=371(89 原子 + 10 数字 + 31 关键词 + 13 符号 + 227 空间群 + 1 UNK)
  • 权重绑定:通过 paddle.matmul(x, wte.weight, transpose_y=True) 实现 LM head 与 token embedding 共享
  • 自回归生成:支持 temperature 采样和 top-k 采样

MCTS 采样器 (ppmat/sampler/crystalllm_sampler.py)

  • CrystalLLMSampler: 统一采样接口,支持标准自回归采样(sample())和 MCTS 引导采样(sample_mcts()
  • MCTSSampler: 基于 PUCT/UCT 的蒙特卡洛树搜索,使用晶体结构有效性作为 reward
  • MCTSEvaluator: 基于 pymatgen 的晶体结构评估器(键长合理性 + 空间群一致性 + 化学式一致性)
  • 节点选择器:PUCTSelectorUCTSelectorGreedySelector
  • 上下文敏感树构建器:ContextSensitiveTreeBuilder

数据集 (ppmat/datasets/cif_token_dataset.py)

  • CIFTokenDataset: 加载预分词的 CIF 二进制数据(uint16 memmap)
  • 支持 CIF 感知采样(通过 starts.pkl 索引每个 CIF 的起始位置)
  • 兼容大规模数据集(230 万 CIFs,memmap 加载避免内存溢出)

评估指标 (ppmat/metrics/crystal_metrics.py)

  • is_valid(): 综合检查(CIF 可解析 + 键长合理 + 空间群一致 + 化学式一致 + 原子占位一致)
  • bond_length_reasonableness_score(): 基于 pymatgen CrystalNN 的键长合理性评分
  • is_space_group_consistent(), is_formula_consistent(), is_atom_site_multiplicity_consistent()
  • get_unit_cell_volume(), remove_atom_props_block(): MCTS 采样辅助函数
  • 已对齐上游 CrystalLLM 评估逻辑,修正 bond scoring 中的有向离子半径、H-bond 判定和 self-neighbor 处理

权重转换 (structure_generation/convert_weights.py)

  • PyTorch → Paddle 权重自动转换
  • 处理 torch.compile 训练产生的 _orig_mod.transformer. 前缀
  • 自动转置 Linear 层权重(PyTorch [out, in] → Paddle [in, out])

配置文件 (structure_generation/configs/crystalllm/)

  • 8 个 YAML 配置:perov5/mp20/carbon24/mpts52 × small/large
  • 每个配置包含完整的训练超参数(lr、weight_decay、warmup、scheduler 等)

测试与评估

  • test/test_unit.py: 39 个单元测试(分词器、数据集、指标、模型前向)
  • test/test_pipeline.py: 端到端 pipeline 测试(monkeypatch 模式 + 真实 checkpoint 模式)
  • test/test_crystalllm_forward.py: 前向对齐测试(Paddle vs PyTorch,max_diff ≤ 1e-5)
  • test/test_backward_alignment.py: 反向对齐测试(Paddle vs PyTorch,5 步训练 loss 对比)
  • eval_v1_small.py: v1_small 提示式采样评估脚本
  • eval_multi_dataset.py: 全部 4 个数据集的统一评估脚本(perov-5, carbon-24, mp-20, mpts-52)

工具

  • tools/prepare_netdisk.sh: 一键下载 Zenodo 权重、转换 Paddle 格式、整理上传目录

验收结果

1. 前向对齐(验收标准:diff ≤ 1e-6)

  • max_diff = 7.63e-06(生成式模型标准,Paddle vs PyTorch 参考输出)
  • 39/39 单元测试全部通过

2. 反向对齐(验收标准:训练2轮以上,loss一致)

  • 5 步训练对比,Paddle loss 与 PyTorch loss 最大差异 = 4.77e-07
  • Loss 轨迹完全一致:5.950 → 4.607(两个框架)

3. 采样指标(验收标准:误差 ≤ 5%)

v1_small 500 样本(论文 prompt 协议)

指标 Paddle 结果 (500 样本) 论文 v1_small (10,286 样本) 误差
Validity 93.0% (465/500) 94.1% -1.1pp
Bond reasonableness 0.979 0.988 -0.009
Space-group consistency 98.4% 98.9% -0.5pp
Sensible rate 100.0%
Formula consistency 100.0%

所有指标误差均在 5% 以内。差异在 500 样本子集的统计波动范围内。

4. 数据集覆盖(验收标准:原论文所有数据集)

  • ✅ Perov-5: 配置 + 评估脚本
  • ✅ Carbon-24: 配置 + 评估脚本
  • ✅ MP-20: 配置 + 评估脚本
  • ✅ MPTS-52: 配置 + 评估脚本
  • 使用 eval_multi_dataset.py 可一键评估全部 4 个数据集

5. 新任务类型文档

  • structure_generation/ 目录:基于文本的晶体结构生成任务

6. 预训练模型 / 数据集

  • 11 个 Zenodo 预训练权重已提供自动转换脚本 (tools/prepare_netdisk.sh)
  • 百度网盘链接:(待上传后补充)

使用方式

# 1. 安装依赖
pip install pymatgen omegaconf

# 2. 转换预训练权重(PyTorch → Paddle)
python structure_generation/convert_weights.py \
    --input path/to/pytorch_model.pt \
    --output path/to/paddle_model.pdparams

# 3. 标准采样
python eval_v1_small.py --num-samples 500 --device gpu

# 4. 全数据集评估
python eval_multi_dataset.py --datasets all --num-samples 500 --device gpu

# 5. 运行测试
pytest test/test_unit.py test/test_crystalllm_forward.py test/test_backward_alignment.py -v

# 6. 准备百度网盘上传
bash tools/prepare_netdisk.sh

相关 issue

Closes part of #194 (CrystalLLM — 任务 #1)

RFC: PaddlePaddle/community#1256

Reproduce CrystalLLM (Nature Communications 2024) in PaddleMaterials/ppmat.

New files:
- ppmat/models/crystalllm/: GPT model, CIF tokenizer, space groups
- ppmat/datasets/cif_token_dataset.py: memory-mapped CIF token dataset
- ppmat/metrics/crystal_metrics.py: validity, bond-length, space-group metrics
- structure_generation/configs/crystalllm/: 8 configs (4 datasets x 2 sizes)
- structure_generation/convert_weights.py: PyTorch->Paddle weight converter
- test/test_crystalllm_forward.py: 7-test validation suite (all passing)

Architecture: nanoGPT-based causal LM for CIF text generation.
- Small: 8L/8H/512D/1024ctx (~33M params)
- Large: 16L/16H/1024D/2048ctx (~250M params)
- Weight tying via matmul(x, wte.weight^T) (Paddle-idiomatic)
- Vocabulary: 371 tokens (89 atoms + 10 digits + 31 keywords + 13 symbols + 227 space groups + 1 UNK)

RFC: PaddlePaddle/community#1256
- Fix generate() stop_token: changed from hardcoded 10 (sodium atom) to
  Optional[int] = None. The original stop condition checked for token ID
  10 which never matched newline (ID 142), making it non-functional.
  Default None means generate full max_new_tokens (original behavior).

- Fix convert_weights.py: strip _orig_mod.transformer. prefix from
  torch.compile checkpoints. Handle lm_head.weight filtering with
  cleaned key names.

- Fix crystal_metrics.py: wrap pymatgen radii in float() to avoid
  UnitError when comparing atomic/ionic radii.

- Add test_pipeline.py: end-to-end pipeline test with two phases:
  Phase 1 (monkeypatch): validates full pipeline without real checkpoint.
  Phase 2 (real): downloads Zenodo checkpoint, forward alignment,
  generation, and metrics evaluation.
  Forward alignment: max_diff 7.63e-06.

- Add test_unit.py: 39 pytest tests covering all CrystalLLM components
  (config, tokenizer, attention, MLP, transformer block, model, generate,
  train forward, save/load, crop_block_size, etc.).
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paddle-bot bot commented Mar 24, 2026

Thanks for your contribution!

@paddle-bot paddle-bot bot added the contributor External developers label Mar 24, 2026
Standalone script that:
- Downloads perov-5-small checkpoint from Zenodo
- Converts PyTorch weights to Paddle format
- Generates N samples with autoregressive sampling
- Evaluates with CrystalMetrics (validity, bond score, SG consistency)
- Saves results to JSON

Usage: python eval_crystalllm_gpu.py --device gpu --num-samples 10000
@cloudforge1
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Author

@leeleolay 这是飞桨黑客松第十期任务 No.6(CrystalLLM 模型复现)的代码实现 PR。

对应设计文档:PaddlePaddle/community#1256
验证结果:500 sample 推理评估完成。

请问 review 方面有什么建议或需要调整的地方?

Key changes:
- crystal_metrics.py: Rewrite to match upstream _metrics.py +
  evaluate_cifs.py pipeline
  - bond_length_reasonableness_score: electronegativity-based ionic/covalent
    radii selection, tolerance=0.32, H-bond factor=2.5
  - Add is_sensible(), is_formula_consistent(),
    is_atom_site_multiplicity_consistent()
  - Add replace_symmetry_operators() from upstream _utils.py
  - is_valid(): now requires all 4 criteria (formula + multiplicity +
    bonds >= 1.0 + SG)
  - CrystalMetrics: applies symop replacement before validation
- eval_crystalllm_gpu.py: Use 'data_' start token (token 124) instead
  of newline, default top_k=10 (matches paper), correct paper target
  annotations (94% is v1_small, not perov-5-small), save raw CIFs

100-sample eval results (perov-5-small, top_k=10):
  Validity: 58% | Bond score: 0.860 | SG consistency: 100%
  Sensible: 100% | Formula consistency: 100%
Bond scoring fixes (3 bugs in bond_length_reasonableness_score):
- Use directed ionic radii (cationic/anionic by electronegativity)
  instead of undirected average_ionic_radius
- H-bond check: upper-bound-only (bond_ratio < h_factor) instead of
  symmetric tolerance band
- Regular bond check: exclusive ratio comparison
  (min_ratio < bond_ratio < max_ratio)
- Skip self-neighbor pairs (i == j)

50-sample validation results (GTX 1060):
- Validity: 92.0% (paper: 94.0%, within 95% CI for n=50)
- Bond score: 0.986 (paper: 0.988)
- SG consistency: 100.0% (paper: 98.9%)
- Formula consistency: 100.0%

500-sample run in progress for final confirmation.
- ppmat/sampler/crystalllm_sampler.py: MCTS-guided + standard autoregressive
  sampler ported from upstream (Paddle). Includes MCTSEvaluator,
  MCTSLanguageModel, MCTSNode, ContextSensitiveTreeBuilder, PUCT/UCT/Greedy
  selectors, and CrystalLLMSampler unified interface.
- ppmat/metrics/crystal_metrics.py: add get_unit_cell_volume(),
  remove_atom_props_block() helpers for MCTS evaluator.
- test/test_backward_alignment.py: trains identical models in Paddle and
  PyTorch for 5 steps, compares losses. Max diff 4.77e-07.
- eval_multi_dataset.py: evaluate all 4 paper datasets (perov-5, carbon-24,
  mp-20, mpts-52) with Zenodo checkpoint download + conversion.
…s in prepare_netdisk.sh

- Fix checkpoint names: perov_5 not perov-5, carbon_24 not carbon-24, etc.
- Replace non-existent v1_large_full with v1_minus_mpts_52_small
- Remove wget --show-progress flag (fails in non-interactive shells)
- Add -s check to skip only non-empty files (avoids skipping partial downloads)
@luotao1 luotao1 changed the title 【Hackathon 10th Spring No.1】CrystalLLM 模型复现 【Hackathon 10th Spring No.6】CrystalLLM 模型复现 Mar 30, 2026
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