Re: Ang. Re: [Gretl-devel] Bug in help file

On Thu, 13 Sep 2007, Sven Schreiber wrote: I agree with a few extra remarks. The gamma function is not terribly useful, by itself. Its logarithm is. One possibility would be to remove the gamma() function altogether and have users use exp(lngamma(x)) if they need to. Of course this would be quite expensive computationally, but in my experience it is extremely rare to use the gamma function instead of its logarithm in iterative computations. Similar considerations hold for the beta function. The backward compatibility issue could be mitigated by officially deprecating the use of the gamma function, for instance producing a warning each time it is used, with an eye to removing it in a year's time or so. As for the more general point about namespaces: a possible source of confusion could come from using functions as function parameters. In the future, it's not unlikely that we may add a "function" type to the possible parameter type that may be fed into user-written functions. For instance, numerical integration. Imagine you have something like function numint(function f, scalar a, scalar b) scalar dx = 0.01*(b-a) scalar ret = 0 scalar x0 = a + 0.5*dx loop 100 --quiet ret += f(x0) * dx x0 += dx end loop return scalar ret end function Thanks to Allin's foresight, the fact that user-defined functions in gretl are "strongly typed" does help quite a lot here, but still I imagine that the code to handle a case like this would be quite complex. Riccardo (Jack) Lucchetti Dipartimento di Economia Università Politecnica delle Marche r.lucchetti(a)univpm.it http://www.econ.univpm.it/lucchetti