简介:ThepaperconsiderstheKrylov-LanczosandtheEckhoffapproximationsforrecoveringabivariatefunctionusinglimitednumberofitsFouriercoefficients.Theseapproximationsarebasedoncertaincorrectionsassociatedwithjumpsinthepartialderivativesoftheapproximatedfunction.ApproximationoftheexactjumpsisaccomplishedbysolutionofsystemsoflinearequationsalongtheideaofEckhoff.AsymptoticbehaviorsoftheapproximatejumpsandtheEckhoffapproximationarestudied.Exactconstantsoftheasymptoticerrorsarecomputed.Numericalexperimentsvalidatetheoreticalinvestigations.