Re: [Help-glpk] Ordered sets in GMPL

[Andrew Makhorin]

> It would be better if not only the indexing set of a domain operation
> could be sorted but also the result set:
> set B := setof{(i,j) in A} sorted (x[i],x[j]);

> Both sorting orders (by index, by resultset) are useful.

> I just implemented this as a further value "sortresult" in struct DOMAIN,
> which I evaluate for O_SETOF in function eval_elemset(). A call to newly
> introduced sort_elemset() does the job.

The point is that the set is not the same as array, and formally it is
an unordered collection. In which context do you need a set to be ordered?

> Is the help list the right way to communicate ideas about enhancing
> GLPK?

Yes, it is. Help-glpk is a main list used to discuss all aspects of GLPK,
including development and porting.