6- 42  Cholleskyֽ⡣
⣺Enterȷϡ
>> A=[4 -1 -1;-1 4.25 2.75;1 2.75 3.5]
A =
    4.0000   -1.0000   -1.0000
   -1.0000    4.2500    2.7500
    1.0000    2.7500    3.5000
>> R=chol(A)
R =
    2.0000   -0.5000   -0.5000
        0    2.0000    1.2500
        0        0    1.2990
>> R'
ans =
    2.0000         0         0
   -0.5000    2.0000         0
   -0.5000    1.2500    1.2990
>> A=[0 4 0;3 0 1;0 1 3]
A =
     0     4     0
     3     0     1
     0     1     3
>> R=chol(A)
??? Error using ==> chol
Matrix must be positive definite.
>>
