WP6: Uncertainty Quantification

WP6 quantifies uncertainties in complex multiscale simulations through sensitivity analysis, surrogate modeling, and high-dimensional integration, leveraging exascale computing for tractable UQ workflows.

Recent Highlights (2024-2025)

Kernel-Based Sensitivity

Global sensitivity analysis methods with kernel-based dependence measures

UQ Platforms

Uranie and OpenTURNS platforms for uncertainty quantification

Integrated Analysis

Sensitivity analyses linked with WP3 solvers and WP2 surrogates

EuroHPC UQ

Initial UQ pipelines exercised on EuroHPC resources

1. Objectives

Uncertainty Quantification includes several critical steps:

  • Uncertainty propagation through complex multiscale models

  • Sensitivity analysis to understand important often correlated factors

  • Reduce uncertainty through modeling improvements in WP1

  • Establish robust inversion or optimization under uncertainties

2. Approach

Diagram

3. Key Tasks

T6.1: Kernel-Based Sensitivity Analysis

  • Handle very high-dimensional and multivariate data in exascale applications

  • Develop tractable extensions of sensitivity analysis built upon kernel-based dependence measures

  • Investigate optimized computing schemes of high-dimensional integrals

  • Support uncertainty propagation step

T6.2: UQ in a PDE Solving Framework

  • Propagate uncertainties (initial conditions, coefficients) in complex PDE solutions

  • Use machine learning and stochastic spectral methods for suitable approximations

  • Address calibration challenges that exceed underlying problem size by orders of magnitude

  • Make HPC strategies mandatory for tractable solutions

T6.3: Surrogate Modeling for UQ

  • Address complex multi-physics and/or multi-scale problems with coupled, nested and chained numerical codes

  • Build and calibrate global metamodel assembling all prediction uncertainties

  • Requires HPC for this formidable task

T6.4: Acceleration via Exascale Calculations

  • Integrate methodological developments of Tasks 6.1 to 6.3

  • Use opensource platforms Uranie and OpenTURNS dedicated to uncertainty quantification

  • Take advantage of exascale computational properties

  • Conduct benchmarking on exascale applications

4. Leads & Partners

Lead Institution

École Polytechnique

Co-Leaders

CEA, UNISTRA

Duration

Months 1-60

5. Addressed Exascale Bottlenecks

WP6 targets bottlenecks B8 (Discovery, design, and decision algorithms) and B13 (Opportunity to integrate uncertainties):

  • Enabling ensembles of many small runs for UQ

  • Integrating uncertainties directly into core calculations

  • Handling high-dimensional integrals at scale

  • Efficient parameter sweeps for sensitivity analysis

6. Deliverables

ID Title Due Dates

D6.1-MR

Activity reports (included in annual report D0.2-TR)

M24, M36, M48, M60

D6.2-S

Software release of URANIE

M48, M60

D6.3-B

Benchmarking analysis report (bottlenecks and breakthroughs)

M12, M24, M36, M48, M60

7. Collaborations

  • WP1: Modeling improvements to reduce uncertainty

  • WP2: Multi-fidelity models for UQ (T6.3)

  • WP4: Shared interest in stochastic methods and uncertainty integration

  • WP5: Optimization under uncertainty

  • WP7: Benchmarking analysis and integration