Multilevel randomized quasi-Monte Carlo estimator for nested integration

  • Bartuska, Arved (KAUST)
  • Carlon, Andre (RWTH Aachen)
  • Espath, Luis (University of Nottingham)
  • Krumscheid, Sebastian (KIT)
  • Tempone, Raul (KAUST)

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Nested integration problems arise in various scientific and engineering applications, including Bayesian experimental design, financial risk assessment, and uncertainty quantification. These nested integrals are computationally challenging, particularly in high-dimensional settings. Although widely used for single integrals, traditional Monte Carlo (MC) methods can be inefficient when encountering complexities of nested integration. In this talk, we discuss a novel multilevel estimator, combining deterministic and randomized quasi-MC methods to handle nested integration problems efficiently. In this context, the inner number of samples and the discretization accuracy of the inner integrand evaluation constitute the level. We provide a comprehensive theoretical analysis of the estimator, deriving error bounds that demonstrate significant reductions in bias and variance compared with standard methods. The proposed estimator is particularly effective in scenarios where the integrand is evaluated approximately, as it adapts to different levels of resolution without compromising precision.