Number of input arguments of cfit,
sfit, or fittype object
nargs = numargs(fun)
nargs = numargs(fun) returns the number of
input arguments nargs of the cfit,
sfit, or fittype object
fun.
f = fittype('a*x^2+b*exp(n*x)');
nargs = numargs(f)
nargs =
4
args = argnames(f)
args =
'a'
'b'
'n'
'x'