Restarted FOM Augmented with Ritz Vectors for Shifted Linear Systems

(整期优先)网络出版时间:2006-01-11
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TherestartedFOMmethodpresentedbySimoncini[7]accordingtothenaturalcollinearityofallresidualsisanefficientmethodforsolvingshiftedsystems,whichgeneratesthesameKrylovsubspacewhentheshiftsarehandledsimultaneously.However,restartingslowsdowntheconvergence.WepresentapracticalmethodforsolvingtheshiftedsystemsbyaddingsomeRitzvectorsintotheKrylovsubspacetoformanaugmentedKrylovsubspace.NumericalexperimentsillustratethattheaugmentedFOMapproach(restartedversion)canconvergemorequicklythantherestartedFOMmethod.