Title
Effect of the separated approximation of input data in the accuracy of the resulting PGD solution
Abstract
The proper generalized decomposition (PGD) requires separability of the input data (e.g. physical properties, source term, boundary conditions, initial state). In many cases the input data is not expressed in a separated form and it has to be replaced by some separable approximation. These approximations constitute a new error source that, in some cases, may dominate the standard ones (discretization, truncation...) and control the final accuracy of the PGD solution. In this work the relation between errors in the separated input data and the errors induced in the PGD solution is discussed. Error estimators proposed for homogenized problems and oscillation terms are adapted to asses the behaviour of the PGD errors resulting from approximated input data. The PGD is stable with respect to error in the separated data, with no critical amplification of the perturbations. Interestingly, we identified a high sensitiveness of the resulting accuracy on the selection of the sampling grid used to compute the separated data. The separation has to be performed on the basis of values sampled at integration points: sampling at the nodes defining the functional interpolation results in an important loss of accuracy. For the case of a Poisson problem separated in the spatial coordinates (a complex diffusivity function requires a separable approximation), the final PGD error is linear with the truncation error of the separated data. This relation is used to estimate the number of terms required in the separated data, that has to be in good agreement with the truncation error accepted in the PGD truncation (tolerance for the stoping criteria in the enrichment procedure). A sensible choice for the prescribed accuracy of the PGD solution has to be kept within the limits set by the errors in the separated input data.
Year
DOI
Venue
2015
10.1186/s40323-015-0052-6
Adv. Model. and Simul. in Eng. Sciences
Keywords
Field
DocType
Proper generalized decomposition, Error assessment, Separable functions
Truncation error,Truncation,Boundary value problem,Discretization,Interpolation,Separable space,Algorithm,Sampling (statistics),Mathematics,Estimator
Journal
Volume
Issue
ISSN
2
1
2213-7467
Citations 
PageRank 
References 
1
0.41
3
Authors
5
Name
Order
Citations
PageRank
Sergio Zlotnik131.17
Pedro Díez252.26
David Martínez González311411.19
E Cueto4356.79
A. Huerta553.76