Problem 486. Surface Fit z(x,y)

Given three vectors x,y,z. Find four coefficients c = [cxx cxy cyy c00], such that z = cxx*x.^2+cxy*x.*y+cyy*y.^2+c00.

For example,

 x = [ 0  0  1  1  2  2  3  3]
 y = [ 0  1  0  1  0  1  0  1]
 z = [-4 -1 -3 -2  0 -1  5  2]

then

 z = x.^2-2*x.*y+3*y.^2-4

and

 c = [cxx cxy cyy c00] = [1 -2 3 -4]

Solve

Last solution submitted on Jun 13, 2018

Tim on 12 Mar 2012

The test suite does not allow for roundoff error.

AMITAVA BISWAS on 12 Mar 2012

good point, fixed, thanks