Sets the absolute tolerance for objective function f(x).
Equivalent in C API: nlopt_set_ftol_abs
Params: tol = value of tolerance, default determined by enum defaultTol
auto opt = Opt(Algorithm.auglag, 2); opt.setFTolAbs(1e-4); assert(opt.getResult() > 0);
See Implementation
Sets the absolute tolerance for objective function f(x).
Equivalent in C API: nlopt_set_ftol_abs