An Adaptive Pruning Algorithm for the Discrete L-Curve Criterion

Per Christian Hansen, Toke Koldborg Jensen, Giuseppe Rodriguez

AbstractWe describe a robust and adaptive implementation of the L-curve criterion, i.e., for locating the corner of a discrete L-curve consisting of a log-log plot of corresponding residual and solution norms of regularized solutions from a method with a discrete regularization parameter (such as truncated SVD or regularizing CG iterations). Our algorithm needs no pre-defined parameters, and in order to capture the global features of the curve in an adaptive fashion, we use a sequence of pruned L-curves that correspond to considering the curves at different scales. We compare our new algorithm to existing algoritms and demonstrate its robustness by numerical examples.
KeywordsDiscrete ill-posed problems, L-curve criterion, regularization, parameter-choice method.
TypeTechnical report
Year2004
PublisherInformatics and Mathematical Modelling, Technical University of Denmark, DTU
AddressRichard Petersens Plads, Building 321, DK-2800 Kgs. Lyngby
SeriesIMM-Technical Report-2004-18
NoteThis work was supported in part by grant no. 21-03-0574 from the Danish Natural Science Research Foundation, and by COFIN grant no. 2002014121 from MIUR (Italy)
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IMM Group(s)Scientific Computing