Re: [Help-glpk] GLPK reading <LP-file> problem

[Andrew Makhorin]

On Fri, 2017-06-16 at 09:07 -0500, Shuo Xu wrote:
> well, this is not the case I was trying to talk. 
> 
> My problem is that if c and A are highly sparse. 
> 
> (I see your source code is using a net-structure to analyze (read
> write )the A structure. 
> 
> the net you built to analyze the structure of A and c is not a
> complete net to re-create the original A and c from LP-file. 
> 
> 
> And, we are trying to use GLPK to write and read LP-files, because we
> are trying to make our cases exchangeable between different
> researchers. 

> And, most solvers are supporting LP file without problem, such as CBC,
> LP_solve, Cplex, AMPL, GAMS, and SCIP. 
> 

On using other packages you will encounter the same issue, because, as I
mentioned earlier, cplex lp format doesn't allow encoding lp/mip in a
general form. AFAIK, for example, cplex changes the instance on writing
it to a file if it has double-bounded rows. If you need maximum
portability, it is better to use the free mps format (it is supported by
all packages you named) rather than the cplex lp format.