[R] polynomial fit

[Karim Elsawy]

Hi
I would like to fit a function H = F(x,y,z) but I do not know the
analytical expression
of H, is there a way to get the best 3d polynomial (in x,y,z) which fits
H
e.g
H<-seq(2,200,len=50)
x<-seq(1,50,len=50)
y<-seq(50,300,len=50)
x<-seq(30,80,len=50)

so it is  a sort of fitting a 4 dimensional surface to a regular grid

any suggestions are very much appreciated
best regards
Karim