.6. .
[[.1], . 262-265; [.2], .69-73; [.3], . 95-98]
- , = *.
1. = LL*, L , lij = 0, i < j.
Ax = f; x = f.
:
.
, . :
:
= LL*:
1. . , 䒺 . . .
2. , = 0 ( ). , - LL*.
1 , .
2. = LDL*, L , D - , , . :
. lkk = 0, k<n, = LDL* .
, L*x = z, Dz = y, Ly = f,
3. = LDL*, L , D - . , dii , ' 1. :
, , . lkk = 0, k<n, .
.
, = LDU, L U ; D .
, , :
k = 1, , n
j = k+1, , n
j;
k;
, Ax = LDUx = f Ux = z, Dz = y, Ly = f,
.
(p+1+q) -,
aki = 0 i - k > p (p ) k - i > q (q ).
i - k > p mki = 0, k - i > q lki = 0.
.
[.1], , . . .: , 1987.
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[.2] , . . .: . 1989.
[.3] . . .. . 1986.