简介:ThispaperdevelopsaclaseofquadratureformulawithfirstderivativesItisdemonstratedthatitsdegreeofaccuracyisnotlessthan2k+1forasetofdistinctnodes{x0,x1,...,xn}overinterval[a,b],andjustonly2k+1forequallyspacednodes.FarovercomingtheshortcomingofinvolvingagreatnumberofmanualcomputationsfortheintegrationrulesoftheHermitianinterpolationformula,somesimpleformulasforcomputingautomaticallyβi,γiandE[f]bycomputeraregiven,especiallyforequallyspacednodes.
简介:Considersolvinganoverdeterminedsystemoflinearalgebraicequationsbyboththeleastsquaresmethod(LS)andthetotalleastsquaresmethod(TLS).Extensivepublishedcomputationalevidenceshowsthatwhentheoriginalsystemisconsistent.oneoftenobtainsmoreaccuratesolutionsbyusingtheTLSmethodratherthantheLSmethod.ThesenumericalobservationscontrastwithexistinganalyticperturbationtheoriesfortheLSandTLSmethodswhichshowthattheupperboundsfortheLSsolutionarealwayssmallerthanthecorrespondingupperboundsfortheTLSsolutions.InthispaperwederiveanewupperboundfortheTLSsolutionandindicatewhentheTLSmethodcanbemoreaccuratethantheLSmethod.Manyappliedproblemsinsignalprocessingleadtooverdeterminedsystemsoflinearequationswherethematrixandrighthandsidearedeterminedbytheexperimentalobservations(usuallyintheformofalimeseries).Itoftenhappensthatasthenumberofcolumnsofthematrixbecomeslarger,thera
简介:
简介:Inthispaper,analmostP-stabletwo-stepsixth-orderHybridmethodwithphase-lagoforderinfinityandaclassexpliciteighth-orderObreckoffmethodswithphase-lagoforder10-24aredevelopedforthenumericalintegrationofthespecialsecond-orderperiodicinitial-valueproblems.Thesemethodshavetheadvantageofhigheralgebraicorderandconsiderablysmallerphase-tagcomparedwithsomemethodsin[1-6].Numericalexamplesindicatethatthesenewmethodsaremoreaccuratethanmethodsdevelopedby[1-6].
简介:Inthispaper,ahighaccuracyfinitevolumeelementmethodispresentedfortwo-pointboundaryvalueproblemofsecondorderordinarydifferentialequation,whichdiffersfromthehighordergeneralizeddifferencemethods.Itisprovedthatthemethodhasoptimalorderer-rorestimateO(h3)inH1norm.Finally,twoexamplesshowthatthemethodiseffective.