... definition ofBwe haveBϕ(k)= bu(k)1,and consequently,bu(k)= Bϕ(k)− F.In view of this, rewriting (19) in the formϕ(k+1)− ϕ(k)τ+ ϕ(k)+ bu(k)= 0 (20)232DANG QUANG A, LE TUNG SONwe ... computational complexity ofO(MNlog2N).We perform some limited experiments in MATLAB for testing the convergence of theiterative process (17)—(19) in dependence on iterative parameterτand ... 54—59(Russian).[5] Dang Quang A, Approximate method for solving an elliptic problem with discontinuouscoefficients, Journal of Comput. and Appl. Math. 51 (1994) 193—203.[6] Dang Quang A, Boundary...