Re: [Gretl-devel] c code question

On Mon, 16 Oct 2017, > oleg_komashko(a)ukr.net wrote: > Thank you, Allin > Also, does it contain > elementary functions > in complex argument e.g. > exp(), log(), etc as in libc? > I can't tell on the future, > what I want to do now > is to make gradient and Hessian > for real functions of real arguments > with imaginary steps inside: > e.g. for gradient: > Im(f(x+i*delta_x)-f(x))/delata_x > > It is very exact, but very slow > if it is not coded in c > Due to the nature of complex numbers > delta_x = $macheps for any real x > The precision does not depends on x > That's why it is so exact I fail to see how this approach can give more precise results than the mechanism we have now. ------------------------------------------------------- Riccardo (Jack) Lucchetti Dipartimento di Scienze Economiche e Sociali (DiSES) Università Politecnica delle Marche (formerly known as Università di Ancona) r.lucchetti@univpm.ithttp://www2.econ.univpm.it/servizi/hpp/lucchetti ------------------------------------------------------- _______________________________________________ Gretl-devel mailing list Gretl-devel@lists.wfu.eduhttp://lists.wfu.edu/mailman/listinfo/gretl-devel