Geometry Meets Physics: Data-Efficient Pre-Training for Unstructured Neural PDE Solvers
Organizations: Technical University of Munich · University of Stuttgart
Abstract
Neural surrogate models for Partial Differential Equations (PDEs) on unstructured 3D geometries are often limited by poor generalization and the high cost of generating large-scale training datasets. Consequently, pre-training on massive datasets of related PDE dynamics has emerged as a critical alternative to enhance the robustness and scalability of these models. However, this strategy is neither compute- nor data-efficient, as it relies on massive pre-computed data that is very costly to generate. In this work, we introduce a disk-data-free pre-training framework tailored to both steady-state and transient regimes. For steady-state problems, we propose a geometry-driven strategy that leverages intrinsic shape descriptors to learn representations of complex 3D domains. For transient problems, we introduce a physics-driven approach based on online generation of synthetic PDE data, enabling scalable pre-training without reliance on expensive datasets. Across multiple experiments, our approach achieves faster convergence, greater data efficiency, and higher accuracy during fine-tuning, particularly under realistic low-data regimes. This methodology provides a practical pathway toward data-efficient neural emulators for large-scale simulations.
Figures & tables
| Property | Traditional FM | Zhang et al. [17] | GeoPT | GMP (Ours) |
|---|---|---|---|---|
| Physics-label-free | ✗ | ✓ | ✓ | ✓ |
| Low pre-training cost | ✗ | ✓ | ✗ | ✓ |
| Unique pre-training | ✓ | ✗ | ✓ | ✓ |
| No high-detail CAD geometries | ✗ | ✗ | ✓ | ✓ |
| Zero disk storage | ✗ | ✗ | ✗ | ✓ |
| Dataset | Time | Dim. | Type | # Samples | # Points (S;V) | # Fields |
|---|---|---|---|---|---|---|
| DrivAerML [ 56 ] | Steady | 3D | S; V | 500 | 9M ; 160M | 4+4 |
| SHIFT-Wing [ 57 ] | Steady | 3D | S; V | 6000 | 3M ; 6M | 4+4 |
| KS (ours) | Transient | 2D | V | 630 30 | - ; 4096 | 1 |
| Ellipse [ 59 ] | Transient | 2D | V | 1200 100 | - ; 1024 | 3 |
| SHIFT-Crash [ 58 ] | Both | 3D | S | 768 12 | 400K ; - | 4 |
| DrivAerML | SHIFT-Wing | SHIFT-Crash | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Training samples | 16 | 32 | 64 | 128 | 16 | 32 | 64 | 128 | 16 | 32 | 64 | 128 |
| Transolver++ (scratch) | 0.685 | 0.559 | 0.329 | 0.180 | 0.603 | 0.403 | 0.235 | 0.209 | 0.611 | 0.601 | 0.548 | 0.328 |
| Transolver++ (GeoPT) | 0.520 | 0.443 | 0.309 | 0.218 | 0.308 | 0.266 | 0.233 | 0.204 | 0.488 | 0.428 | 0.410 | 0.388 |
| Transolver++ (GMP ours) | 0.503 | 0.453 | 0.302 | 0.178 | 0.318 | 0.265 | 0.232 | 0.205 | 0.530 | 0.563 | 0.356 | 0.322 |
| Rel. Improvement | 27% | 19% | 8% | 1% | 47% | 34% | 1% | 2% | 13% | 6% | 34% | 2% |
| AB-UPT (scratch) | 0.439 | 0.313 | 0.244 | 0.184 | 0.569 | 0.456 | 0.379 | 0.298 | 0.396 | 0.363 | 0.340 | 0.326 |
| DrivAerML average | ||||
|---|---|---|---|---|
| Training samples | 16 | 32 | 64 | 128 |
| GMP-Net (scratch) | 0.412 | 0.348 | 0.187 | 0.099 |
| GMP (occupancy) | 0.424 | 0.379 | 0.243 | 0.138 |
| GMP (VDF) | 0.402 | 0.333 | 0.189 | 0.103 |
| GMP (N and C) | 0.387 | 0.311 | 0.182 | 0.101 |
| GMP (all) | 0.346 | 0.299 | 0.178 | 0.097 |
| 2D KS | 2D Ellipse | 3D SHIFT-Crash | |||||||||
| Timesteps | |||||||||||
| Erwin | 0.143 | 0.713 | 1.281 | 0.016 | 0.083 | 0.438 | 0.039 | 0.131 | 0.245 | ||
| Transolver++ | 0.203 | 0.779 | 1.028 | 0.006 | 0.021 | 0.042 | 0.020 | 0.072 | 0.072 | ||
| GMP-Net (scratch) | 0.030 | 0.196 | 0.615 | 0.008 | 0.025 | 0.044 | 0.009 | 0.030 | 0.040 | ||
| GMP-Net (PT) | 0.024 | 0.148 | 0.479 | 0.006 | 0.020 | 0.033 | 0.008 | 0.026 | 0.034 | ||
| Rel. Improvement | 20% | 24% | 22% | 25% | 20% | 23% | 11% | 13% | 15% | ||
| # Trajectories | 16 | 32 | 64 |
|---|---|---|---|
| GMP-Net (scratch) | 8.8 | 6.9 | 5.4 |
| GMP-Net (PT) | 6.2 | 4.8 | 3.9 |
| Improvement | 29% | 30% | 28% |
Appendix figures & tables86 assets
Supplementary material from the paper’s appendix.
Appendix
| Vol. Points | Surf. Points | PT Time (h) | Rel Error FT (64 samples) |
|---|---|---|---|
| 1024 | 512 | 2.5 | 0.194 |
| 2048 | 1024 | 4.0 | 0.178 |
| 4096 | 2048 | 9.0 | 0.175 |
| Setting | Transolver++ | AB-UPT | GMP-Net |
|---|---|---|---|
| Scratch | 0.329 | 0.244 | 0.187 |
| GMP relative | 0.325 | 0.238 | 0.185 |
| GMP ConFIG | 0.302 | 0.218 | 0.178 |
| Max. Imp | 8% | 17% | 6% |
| DrivAerML | NASA CRM | Car Crash | ||||
|---|---|---|---|---|---|---|
| Training samples | 32 | 64 | 32 | 64 | 32 | 64 |
| Transolver (scratch) | 0.166 | 0.110 | 0.242 | 0.136 | 0.315 | 0.214 |
| Transolver (GeoPT) | 0.126 | 0.090 | 0.203 | 0.113 | 0.235 | 0.192 |
| Rel. Improvement | 24% | 18% | 16% | 17% | 25% | 10% |
| Category | Hyperparameter | Value / Description |
| Data generation | H’, W’, D’ | 32 |
| PDEs | Diffusion, Hyper-diffusion, Burgers, Korteweg-de Vries (KdV), Kuramoto-Sivashinsky (KS), Fisher-KPP, Swift-Hohenberg | |
| Initial conditions | Gaussian noise, Truncated Fourier series, Diffused noise, Decayed Energy, Poisson | |
| Resolution | 64, 128, 256, 384 | |
| # surface points | 1024 | |
| # volume points | 2048 |
| Category | Hyperparameter | Value / Description |
| Data | # surface points | 1024 |
| # volume points | 2048 | |
| Optimization | Optimizer | AdamW |
| Learning Rate | 1e-4 | |
| LR schedule | cosine | |
| Batch Size | 8 |
| Category | Hyperparameter | Value / Description |
| Data | Training/Test split | KS: 580/50 trajectories |
| Ellipse: 1000/200 trajectories | ||
| Crash: 600/100 trajectories | ||
| Optimization | Optimizer | AdamW |
| Max learning Rate | 1e-4 | |
| Lr. schedule | Cosine |
| Category | Hyperparameter | Value / Description |
| Data | Training/Test split | (Varying size from 16 to 128) |
| # points | 32768 (S) + 32768 (V) | |
| Optimization | Optimizer | LION |
| Learning Rate | 1e-4 | |
| LR schedule | Cosine | |
| Batch Size | 1 |
| Category | Hyperparameter | Value / Description |
| Data | Training/Test split | (Varying size from 16 to 128) |
| # points | 32768 (S) + 32768 (V) | |
| Optimization | Optimizer | LION |
| Learning Rate | 1e-4 | |
| LR schedule | Cosine | |
| Batch Size | 1 |
| Category | Hyperparameter | Value / Description |
| Data | Training/Test split | (Varying size from 16 to 128) |
| # points | 32768 | |
| Optimization | Optimizer | LION |
| Learning Rate | 1e-4 | |
| LR schedule | Cosine | |
| Batch Size | 1 |
| Hyperparameter | Value / Description |
|---|---|
| spatial dim | 3 |
| Surface channels | 4 |
| Volume channels | 4 |
| Parameter channels | 16 (DrivAerML) |
| 1 (SHIFT-Wing) | |
| 6 (SHIFT-Crash) |
| Hyperparameter | Value / Description |
|---|---|
| spatial dim | 2 (KS) / 2 (Ellipse) / 3 (Crash) |
| Input surface channels | 0 (KS) / 0 (Ellipse) / 1 (Crash) |
| Input volume channels | 1 (KS) / 3 (Ellipse) / 0 (Crash) |
| Output surface channels | 0 (KS) / 0 (Ellipse) / 1 (Crash) |
| Output volume channels | 1 (KS) / 3 (Ellipse) / 0 (Crash) |
| Parameter channels | 1 |
| Model | DrivAerML | SHIFT-Wing | SHIFT-Crash ∗ | ||
|---|---|---|---|---|---|
| Surface | Volume | Surface | Volume | Surface | |
| PTV3 | 31.33 | 44.31 | 20.87 | 46.76 | 35.25 |
| Erwin | 28.52 | 26.67 | 11.52 | 38.67 | 42.15 |
| Transolver++ | 11.32 | 13.04 | 7.67 | 24.04 | 23.97 |
| GeoTransolver | 10.33 | 10.90 | 7.50 | 24.90 | 23.39 |
| AB-UPT | 10.76 | 8.83 | 10.07 | 25.11 | 39.65 |
| Model | 1 | 5 | 10 |
|---|---|---|---|
| Erwin | 0.143 0.011 | 0.713 0.043 | 1.281 0.073 |
| Transolver++ | 0.203 0.014 | 0.779 0.052 | 1.028 0.035 |
| GMP-Net (scratch) | 0.030 0.003 | 0.196 0.039 | 0.615 0.060 |
| GMP-Net (PT) | 0.024 0.002 | 0.148 0.030 | 0.479 0.073 |
| Model | 1 | 5 | 10 |
|---|---|---|---|
| Erwin | 0.016 0.002 | 0.083 0.034 | 0.438 0.244 |
| Transolver++ | 0.006 0.001 | 0.021 0.003 | 0.042 0.005 |
| GMP-Net (scratch) | 0.008 0.001 | 0.025 0.043 | 0.044 0.009 |
| GMP-Net (PT) | 0.006 0.001 | 0.020 0.004 | 0.033 0.011 |
| Model | 1 | 5 | 10 |
|---|---|---|---|
| Erwin | 0.039 0.001 | 0.131 0.034 | 0.245 0.021 |
| Transolver++ | 0.020 0.016 | 0.072 0.039 | 0.072 0.021 |
| GMP-Net (scratch) | 0.009 0.008 | 0.030 0.017 | 0.040 0.024 |
| GMP-Net (PT) | 0.008 0.007 | 0.026 0.018 | 0.034 0.013 |
| Model | Size (M) | VRAM (GB) | Throughput (it/s) |
|---|---|---|---|
| Erwin [ 43 ] | 6.8 | 2.15 | 2.45 |
| Transolver++ [ 55 ] | 6.9 | 3.50 | 3.27 |
| AB-UPT [ 45 ] | 11.4 | 12.79 | 0.47 |
| SMART [ 46 ] | 11.4 | 9.58 | 0.70 |
| (Entire dataset) | DrivAerML |
|---|---|
| Transolver++ (scratch) | 0.120 |
| Transolver++ (PT) | 0.104 |
| Rel. Improvement | 13% |
| AB-UPT (scratch) | 0.098 |
| AB-UPT (PT) | 0.093 |
| Rel. Improvement | 5% |
| Benchmark | Region | Improvement (%) |
| DrivAerML | Front | 23.5 |
| Mid car | 10.0 | |
| Underbody | 17.4 | |
| Tail / Diffuser | 19.8 | |
| SHIFT-Wing | Leading edge | 21.6 |
| Upper surface | 15.3 |