ThelargescalelinearsystemswithM-matricesoftenappearinawidevarietyofareasofphysical,fluiddynamicsandeconomicsciences.Itisreportedin[1]thattheconvergencerateoftheIMGSmethod,withthepreconditionerI+S_α,issuperiortothatofthebasicSORiterativemethodfortheM-matrix.ThispaperconsidersthepreconditionedJacobi(PJ)methodwiththepreconditionerP=I+S_α+S_β,andprovestheoreticallythattheconvergencerateofthePJmethodisbetterthanthatofthebasicAORmethod.Numericalexamplesareprovidedtoillustratethemainresultsobtained.
