Math 232  LU factorization of a matrix    Jan 17, 2001

A0=A
A0 =
     2    -2     3
     6    -7    14
     4    -8    30
L=eye(3)
L =
     1     0     0
     0     1     0
     0     0     1
A1=A0; A1(2,:)=A0(2,:) - 3*A0(1,:)
A1 =
     2    -2     3
     0    -1     5
     4    -8    30
L(2,1)=3
L =
     1     0     0
     3     1     0
     0     0     1
A2=A1; A2(3,:)=A1(3,:)-2*A1(1,:)
A2 =
     2    -2     3
     0    -1     5
     0    -4    24
L(3,1)=2
L =
     1     0     0
     3     1     0
     2     0     1
U=A2; U(3,:)=A2(3,:)-4*A2(2,:)
U =
     2    -2     3
     0    -1     5
     0     0     4
L(3,2)=4
L =
     1     0     0
     3     1     0
     2     4     1
A
A =
     2    -2     3
     6    -7    14
     4    -8    30
L*U
ans =
     2    -2     3
     6    -7    14
     4    -8    30

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