Beyond Time Induction: Structured Conditional Neural Solvers for Parametric Stochastic-Volatility Pricing
Organizations: University College London, UK · Aicraft, Mexico
Abstract
Physics-informed neural networks provide a flexible framework for learning parametric PDE solution families without labeled data, yet preserving accurate derivatives across heterogeneous regimes remains challenging. Structured neural solvers offer compact representations, but restrictive conditional parameterizations can limit adaptation across the solution family. We introduce BeTINN, a structured conditional architecture extending time-induced modulation through multi-directional time-parameter conditioning and a joint residual pathway. We evaluate BeTINN on the Heston stochastic-volatility PDE, a demanding parametric problem with mixed derivatives and economically relevant first- and second-order sensitivities. BeTINN improves joint accuracy across normalized option value and key sensitivity metrics relative to our baselines. Controlled ablations characterize the roles of its architectural components. We further find that validation physics loss is informative but does not fully determine differential fidelity, and that accurate solution values can coexist with localized derivative errors. These results support structured conditional adaptation and motivate derivative-aware evaluation when sensitivities are downstream quantities of interest.
Figures & tables
| Method | Params | Price MAE | MAE | MAE | MAE |
| TINN | 3,663 | ||||
| PINN | 3,631 | ||||
| PI-DeepONet | 3,511 | ||||
| BeTINN | 3,595 |
Appendix figures & tables26 assets
Supplementary material from the paper’s appendix.
Appendix
| Constraint | Fixed coordinate | Training points |
| PDE interior | — | |
| Initial condition | ||
| Left boundary | ||
| Right boundary |
| Method | Hidden / branch geometry | Conditioning / residual | Params | Mismatch (%) | |
| BeTINN | conditioner ; joint residual | ||||
| TINN | temporal conditioner | ||||
| PINN | — | — | |||
| PI-DeepONet | branch/trunk/latent | — | symmetric geometry | ||
| JointResidual (TINN) | temporal conditioner ; joint residual |
| Subset | Definition | Points |
| ATM tight | 253 | |
| ATM | 501 | |
| ATM wide | 1297 | |
| Very near maturity | 109 | |
| Near maturity | 204 | |
| Short maturity | 520 |
| Model | Params. | Train time (s) | Best val. step | latency (ms) | throughput | throughput | Peak alloc. (MiB) |
| BeTINN | 3595 | 256.7 | |||||
| TINN | 3663 | 160.7 | |||||
| PINN | 3631 | 80.9 | |||||
| PI-DeepONet | 3511 | 99.8 |
| Configuration | Params | Price MAE | MAE | MAE | MAE |
| 1,630 | |||||
| 2,285 | |||||
| 2,940 | |||||
| 3,595 | |||||
| 4,250 | |||||
| 4,905 |
| Backbone | Params | Price MAE | MAE | MAE | MAE |
| , fixed-budget diagnostic | 1,385 | ||||
| 1,915 | |||||
| 2,675 | |||||
| 3,595 |
| Method | Params | Price MAE | MAE | MAE | MAE |
| TINN | 2,727 | ||||
| PINN | 2,623 | ||||
| JointResidual | 2,665 | ||||
| BeTINN | 2,675 |
| Method | Params | Price MAE | MAE | MAE | MAE |
| TINN | 3,663 | ||||
| PINN | 3,631 | ||||
| JointResidual | 3,577 | ||||
| BeTINN | 3,595 |
| Configuration | Params | Mismatch (%) | Price MAE | MAE | MAE | MAE |
| BeTINN (reference) | 3595 | 0.00 | ||||
| TINN | 3663 | 1.89 | ||||
| TINN + parameter conditioning | 3595 | 0.00 | ||||
| TINN + modified-MLP gating | 3625 | 0.83 | ||||
| TINN + highway gating | 3695 | 2.78 | ||||
| TINN + adaptive residual | 3665 | 1.95 |
| Configuration | Params | Price diff. | diff. | diff. | diff. |
| TINN | 3663 | (1/6) | (2/6) | (2/6) | (1/6) |
| TINN + parameter conditioning | 3595 | (0/6) | (0/6) | (0/6) | (0/6) |
| TINN + modified-MLP gating | 3625 | (1/6) | (1/6) | (0/6) | (0/6) |
| TINN + highway gating | 3695 | (1/6) | (1/6) | (2/6) | (1/6) |
| TINN + adaptive residual | 3665 | (1/6) | (1/6) | (0/6) | (1/6) |
| JointResidual | 3577 | (1/6) | (1/6) | (1/6) | (1/6) |
| Baseline | Metric | Mean diff. | Median diff. | BeTINN wins |
| TINN | Price | 6/6 | ||
| 5/6 | ||||
| 6/6 | ||||
| 6/6 | ||||
| PINN | Price | 5/6 | ||
| 4/6 |
| Metric | Method | Price | ||||||
| MAE | BeTINN | |||||||
| TINN | ||||||||
| PINN | ||||||||
| PI-DeepONet | ||||||||
| RMSE | BeTINN | |||||||
| TINN |
| Error metric | Spearman |
| Price MAE | 0.578 |
| MAE | 0.682 |
| MAE | 0.617 |
| MAE | 0.698 |
| Price MAE | MAE | |||||||
| Region | BeTINN | TINN | PINN | PI-DeepONet | BeTINN | TINN | PINN | PI-DeepONet |
| ATM (501) | .00672 | .00934 | .00839 | .0106 | .00992 | .0110 | .0109 | .0141 |
| ATM tight (253) | .00702 | .00987 | .00890 | .0112 | .00978 | .0110 | .0109 | .0135 |
| ATM wide (1297) | .00700 | .00959 | .00860 | .0111 | .00992 | .0110 | .0109 | .0139 |
| ATM wide & short maturity (62) | .00432 | .00417 | .00406 | .00623 | .0174 | .0184 | .0194 | .0306 |
| ATM & near maturity (8) | .00559 | .00479 | .00507 | .00520 | .0318 | .0332 | .0387 | .0741 |
| MAE | MAE | |||||||
| Region | BeTINN | TINN | PINN | PI-DeepONet | BeTINN | TINN | PINN | PI-DeepONet |
| ATM (501) | .0345 | .0398 | .0390 | .0561 | .0102 | .0124 | .0116 | .0174 |
| ATM tight (253) | .0328 | .0398 | .0384 | .0561 | .0101 | .0123 | .0115 | .0171 |
| ATM wide (1297) | .0339 | .0392 | .0383 | .0590 | .0100 | .0124 | .0115 | .0172 |
| ATM wide & short maturity (62) | .188 | .181 | .182 | .307 | .0131 | .0138 | .0133 | .0246 |
| ATM & near maturity (8) | .536 | .402 | .376 | .476 | .00849 | .0110 | .0114 | .0148 |
| Family | Candidate | Depth | Widths | Params | Mismatch (%) | Price | Ranks / mean rank | |||
| TINN | Capacity-matched | 2 | 3663 | 1.89 | 0.007587 | 0.0179 | 0.148 | 0.00725 | 2/2/1/1 1.50 | |
| TINN | Funnel | 2 | 3585 | 0.28 | 0.007585 | 0.0175 | 0.150 | 0.00734 | 1/1/2/2 1.50 | |
| TINN | Depth 3 | 3 | 3483 | 3.12 | 0.009363 | 0.0201 | 0.158 | 0.00873 | 3/3/3/3 3.00 | |
| PINN | Capacity-matched | 2 | 3631 | 1.00 | 0.00859 | 0.01868 | 0.1489 | 0.00816 | 1/2/3/1 1.75 | |
| PINN | Depth 3 | 3 | 3511 | 2.34 | 0.00997 | 0.02016 | 0.1448 | 0.00900 | 3/3/1/3 2.50 | |
| PINN | Depth 4 | 4 | 3697 | 2.84 | 0.00893 | 0.01866 | 0.1451 | 0.00821 | 2/1/2/2 1.75 |
| Method | Params | Price MAE | MAE | MAE | MAE |
| DeepSVM-adapted | 33920 | 0.1258 0.0004 | 0.2073 0.0003 | 0.376 0.002 | 0.0567 0.0004 |
| BeTINN | 3595 | 0.00746 0.00097 | 0.0180 0.0010 | 0.143 0.005 | 0.00712 0.00089 |
| TINN | 3663 | 0.00910 0.00062 | 0.0197 0.0009 | 0.158 0.006 | 0.00853 0.00046 |
| PINN | 3631 | 0.00857 0.00054 | 0.0188 0.0005 | 0.149 0.003 | 0.00800 0.00049 |
| PI-DeepONet | 3511 | 0.00974 0.00063 | 0.0232 0.0007 | 0.199 0.016 | 0.0109 0.0005 |
| PDE | Model | Params | Rel. | MAE |
| Parametric Burgers | PINN | 3017 | ||
| TINN | 2985 | |||
| BeTINN | 2967 | |||
| Parametric Wave | PINN | 3017 | ||
| TINN | 2985 | |||
| BeTINN | 2967 |
Neural PDE Solvers
Neural PDE solvers use trainable models to approximate solutions or solution operators for partial differential equations, often with physical constraints.
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