code digging

Hi,

would anyone plz tell me how can i arrange coeff. for orders above 3??have a problem in understanding of description of coeff.s in following script??i want to make an equation with 6 order but doesn't know how to find arrangement of coeff.s////

http://mathworks.com/matlabcentral/fileexchange/31636-2d-polynomial-fitting-with-svd/content/fit2dPolySVD.m