Question

I have a module which does some non constrained minimization. I’d like to keep its’ interface as simple as possible, so the best choice would be to reduce it to a single function something like: min_of( F ).

But as soon as it is brutal computation, i would have to deal with at least two constants: precision of minimization algorithm and maximum number of iterations, so it would not hang itself if target function doesn’t have local minimum at all.

Anyways, the next best choice is: min_of( F, Iterations, Eps ). It’s ok, but I don’t like it. I would like to still have another min_of( F ) defined something like this:

min_of( F ) ->
    min_of( F, 10000, 0.0001).

But without magic numbers.

I’m new to Erlang, so I don’t know how to deal with this properly. Should i define a macros, a variable or maybe a function returning a constant? Or even something else? I found Erlang quite expressive, so this question seems to be more of a good practice, than technical question.

Answer 1

You can define macros like this

-define(ITERATIONS, 10000).
-define(EPS, 0.0001).

and then use them as

min_of(F, ?ITERATIONS, ?EPS).