I need to fit a model to a function of two variables which I have stored in a large CSV table. It's of the form f(r,z) = t, where r,z,and t are the first, second and sixth columns of the table respectively. I can load the table OK using Import[...]. I've defined my model like this:
model = A*r^2 + B*r*z+C*z^2+D
What I can't figure out is how to tell mathematica which data column is which, and that A,B,C,D are the parameters of the model I am trying to find. Can someone please walk me through it?