52 J.Zhao Appl.Math.Comput.92 (1998:49 58 i<i. i=j. (7) (au-∑laly)/ln.i>i月 i.j=1: Set LB=lg,=B(L)∈R"m Then all elements g;can be obtained from the following: (8) Since LyLT=C+LaLg let Lw=比∈E”“ be low triangular. Hence i<j. +- i=1 (c+∑gag-∑Crn)/r元 i>1: i=1:n.j=1:n (9) From the above discussion.the triangular factor of G can be obtained pro- vided that submatrices L.L and L have been formed.i.e.. 4=(位) and =(日)》 Using the factorization expression G=LiL