Implementation of optimal Galerkin and Collocation approximations of PDEs with Random Coefficients

Implementation of optimal Galerkin and Collocation approximations of PDEs with Random Coefficients

Back, F. Nobile, L. Tamellini and R. Tempone. Implementation of optimal Galerkin and Collocation approximations of PDEs with Random Coefficients, in ESAIM Proceedings, vol. 33, p. 10-21, 2011.

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Back, F. Nobile, L. Tamellini and R. Tempone
Uncertainty Quantification / PDEs with random data / elliptic equations / multivariate polynomial approximation / Best M-Terms approximation / Stochastic Galerkin methods / Smolyak approximation / Sparse grids, Stochastic Collocation methods
2011
In this work we first focus on the Stochastic Galerkin approximation of the solution u of an elliptic stochastic PDE. We rely on sharp estimates for the decay of the coefficients of the spectral expansion of u on orthogonal polynomials to build a sequence of polynomial subspaces that features better convergence properties compared to standard polynomial subspaces such as Total Degree or Tensor Product.
We consider then the Stochastic Collocation method, and use the previous estimates to introduce a new effective class of Sparse Grids, based on the idea of selecting a priori the most profitable hierarchical surpluses, that, again, features better convergence properties compared to standard Smolyak or tensor product grids.