eprintid: 1712 rev_number: 6 eprint_status: archive userid: 46 dir: disk0/00/00/17/12 datestamp: 2013-09-13 09:51:09 lastmod: 2013-09-16 12:03:00 status_changed: 2013-09-13 09:51:09 type: article metadata_visibility: no_search creators_name: Gnecco, Giorgio creators_name: Sanguineti, Marcello creators_id: giorgio.gnecco@imtlucca.it creators_id: title: Accuracy of suboptimal solutions to kernel principal component analysis ispublished: pub subjects: QA75 divisions: CSA full_text_status: none keywords: Principal component analysis (PCA); Kernel methods; Suboptimal solutions; Primal and dual problems; Lagrangian; Regularized optimization problems abstract: For Principal Component Analysis in Reproducing Kernel Hilbert Spaces (KPCA), optimization over sets containing only linear combinations of all n-tuples of kernel functions is investigated, where n is a positive integer smaller than the number of data. Upper bounds on the accuracy in approximating the optimal solution, achievable without restrictions on the number of kernel functions, are derived. The rates of decrease of the upper bounds for increasing number n of kernel functions are given by the summation of two terms, one proportional to n −1/2 and the other to n −1, and depend on the maximum eigenvalue of the Gram matrix of the kernel with respect to the data. Primal and dual formulations of KPCA are considered. The estimates provide insights into the effectiveness of sparse KPCA techniques, aimed at reducing the computational costs of expansions in terms of kernel units. date: 2009 date_type: published publication: Computational Optimization and Applications volume: 42 number: 2 publisher: Springer pagerange: 265-287 id_number: 10.1007/s10589-007-9108-y refereed: TRUE issn: 0926-6003 official_url: http://dx.doi.org/10.1007/s10589-007-9108-y citation: Gnecco, Giorgio and Sanguineti, Marcello Accuracy of suboptimal solutions to kernel principal component analysis. Computational Optimization and Applications, 42 (2). pp. 265-287. ISSN 0926-6003 (2009)