Re: Can't get exact solution. Why ?

<eigen21@xxxxxxxxx> wrote in message
news:1140768240.033400.123560@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I'm using Compaq Visual fortran 6.1 (window XP platform)

My problem is simple

I hope to solve x of A*x = b

A = [ 4 2 0 0 0 0 ;
2 4 2 0 0 0 ;
0 2 4 2 0 0 ;
0 0 2 4 2 0 ;
0 0 0 2 4 2 ;
0 0 0 0 2 4 ] --> symmetric

b = [1;1;1;1;1;1]

In matCAD. I can get solution
x =
0.214
0.071
0.143
0.143
0.071
0.214


In Matlab, A is well conditioned wrt inversion and inv(A)*b =

2.142857142857143e-001
7.142857142857151e-002
1.428571428571428e-001
1.428571428571429e-001
7.142857142857140e-002
2.142857142857143e-001

more or less the same as MatCAD.


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