Mathlab and least square problem

[hytuoc]

Does anyone know how accurate is MATLAB in calculating least square solution?
Thanks!

 

[Dr Transport]

To what problem?

 

[hytuoc]

A=[1,1,1;-1,3,1;2,3,-2;1,3,2] A is 4X4

b=[4;0;1;2] ; b is 4X1

I calculated x^ (residual of x) to be [1.4127; -.0159; .8889]
r(x^) = b-A*x^ = [1.7143; 0.5714; 0; -1.1429]
Nul(A')=[-1.5;-.5;0;1]
so how accurate is MATLAB in calculating least square solution?

 

[hytuoc]

anyone know the answer to my question above?

 

[LeBrad]

Are you asking how does Matlab choose the solution when you give it an overdetermined system?