Re: [Help-glpk] un reduced filed

[Andrew Makhorin]

> Right.  I'm aware that I don't need to specify them, but they're in the 
> LP output of another like program, with which I've recently become 
> acquainted.  I'm asking why does GLPK leaves them in?  Aren't they 
> superfluous.

The only case in which a zero coefficient may appear is an empty row
(otherwise, it would be impossible to include such row due to syntactic
restrictions of cplex lp format). 

> In a similar vein, is it possible to presolve *without* solving?  

Currently not, because an internal lp instance produced by the lp
preprocessor is not available on api level. If you would like to hack
it, see the routine preprocess_and_solve_lp in file glpapi06.c; the
internal lp object is created by a call to npp_build_prob.