[Symphony] bicriteria example?

[Ted Ralphs]

Something does seem to be broken with the bicriteria solve capability.
We'll take a look at it and get back to you.

Cheers,

Ted

On Mon, May 3, 2010 at 4:09 PM, Ross Anderson <rpanderson at gmail.com> wrote:
> Hi all,
> I'm attempting to reproduce the bicriteria example found in many of the
> presentations (like the Advanced DIMACS06 tutorial). Here's the problem
> reproduced:
> vmax [8x1, x2],
> subject to 7x1 + x2 <= 56,
> 28x1 + 9x2 <= 252,
> 3x1 + 7x2 <= 105,
> x1, x2 >= 0
>
> Here's my MPS file:
>
> NAME          BICRIT
> ROWS
>  N  COST
>  L  LIM1
>  L  LIM2
>  L  LIM3
> COLUMNS
>     XONE      COST                -8   LIM1                 7
>     XONE      LIM2                 28  LIM3                 3
>     XTWO      COST                -1   LIM1                 1
>     XTWO      LIM2                 9   LIM3                 7
> RHS
>     RHS1      LIM1                 56  LIM2                252
>     RHS1      LIM3                105
> BOUNDS
>  LI BND1      XONE                 0
>  LI BND1      XTWO                 0
> ENDATA
>
>
> and the tutorial code:
>
> #include "symphony.h"
>
> int main(int argc, char **argv)
> {
>
>    sym_environment *env = sym_open_environment();
>    sym_parse_command_line(env, argc, argv);
>    sym_load_problem(env);
>
>    sym_set_obj2_coeff(env, 1,1);
>    sym_mc_solve(env);
>
>    sym_close_environment(env);
>
>    return(0);
>
> }
>
>
> The solver screen outputs  XONE      8.000  (implying XTWO is 0), which is
> the outcome for \theta in (-infty, 1.333). How do I go about finding the
> other ranges? I also tried passing mc_find_supported_solutions 1 in a
> parameter file - no change.
>
> Thank you.
>
> _______________________________________________
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>
>



-- 
Dr. Ted Ralphs
Associate Professor, Lehigh University
(610) 628-1280
ted 'at' lehigh 'dot' edu
coral.ie.lehigh.edu/~ted