If the regression function is in right MATLAB notation
f(x) = (a+b*x.*z)./(1+c*x) % see dots between x and z and before /!,
the coefficients a, b and c may be found by the application of the function LMFnlsq from File Exchange, see
www.mathworks.com/matlabcentral/fileexchange/17534
for a nonlinear regression. The problem may be tranformed into linear one in unknown coefficients:
f(x).*(1+c*x) = a+b*x.*z
The solution of this problem by a linear regression, a0, b0, c0 can serve as a good initial guess for the nonlinear regression of the original nonlinear problem.
