[Couenne] Error in _cmdno 308 / can't open C:\Users\...\Temp\at1988.sol

[Pietro Belotti]

Dear Tom,

I can reproduce this behavior. This seems due to an early
infeasibility detection which skips branch and bound altogether.
However, this also skips writing the .sol file, which, as you note,
should be done nonetheless, since the writing bit is placed
(erroneously) at the end of the BB procedure. I am fixing it now and
hope to commit the changes to the SVN repository soon.

Pietro

On Tue, Dec 2, 2014 at 12:52 PM, Tom Van Acker
<Tom.VanAcker at esat.kuleuven.be> wrote:
> Dear reader,
>
>
>
> I am programming a topology optimization for a meshed power system. The
> problem is a Mixed Integer Non Convex Quadratic Constraint Problem and to
> solve this I am using Couenne as a solver in AMPL. The solution to the
> problem allows several options of adjusting the topology. Certain topology
> adjustments could lead to an infeasible solution, in that case another
> topology adjustment should be tried. If I try to solve the problem using a
> topology adjustment that leads to an infeasible solution I get the following
> output in AMPL:
>
>
>
> Couenne 0.4.7 --  an Open-Source solver for Mixed Integer Nonlinear
> Optimization
>
> Mailing list: couenne at list.coin-or.org
>
> Instructions: http://www.coin-or.org/Couenne
>
> couenne:
>
> ANALYSIS TEST:  Couenne: Warning, tightened NLP is infeasible
>
> problem infeasible
>
> Error at _cmdno 308 executing "solve" command
>
> (file TOPOP.run, line 96, offset 3162):
>
> can't open C:\Users\tvanacke\AppData\Local\Temp\at1988.sol
>
>
>
> And after this error, the program is interrupted (after the solve; line),
> which it should not do. In a correct situation it should move on to another
> topology switching possibility (mode), as can be seen in the code. Is there
> any way to address this problem so the optimization can be continued?
>
>
>
> repeat                                                                    {
>
> if (mode == 3 and submode > 2)                        then {
>
>
>
>        drop {g in G}                                  GBC[g];
>
>        restore {g in G}                               GBO[g];
>
>
>
>        option                                         solver couenne;
>
>        option                                         lp_solver cplex;
>
>        solve;
>
>
>
>        let                                            mode := 4;
>
>        if solve_result_num < 100                      then {
>
>              let                                     submode := 999;
>
>              print
> '------------------------------------SUBOPTIMAL SOLUTION
> FOUND-------------------------------------';
>
>              display                                  Isc;
>
>              display                                 D;
>
>              display                                 OBJ2;
>
>              print
> '--------------------------------------------------------------------------------------------------';
>
>        }
>
> }
>
> if (mode == 2 and submode > 1)                        then {
>
>
>
>        drop {bi in BI}                                       BIBC[bi];
>
>        drop {bo in BO}                                       BOBC[bo];
>
>        restore {bi in BI}                                    BIBO[bi];
>
>        restore {bo in BO}                                    BOBO[bo];
>
>
>
>        option                                                solver couenne;
>
>        option                                                lp_solver
> cplex;
>
>        solve;
>
>
>
>        let                                                   mode := 3;
>
>        if solve_result_num < 100                      then {
>
>              let                                            mode := 4;
>
>              let                                            submode := 999;
>
>              print
> '------------------------------------SUBOPTIMAL SOLUTION
> FOUND-------------------------------------';
>
>              display                                        Isc;
>
>              display                                        D;
>
>              display                                        OBJ2;
>
>              print
> '--------------------------------------------------------------------------------------------------';
>
>        }
>
> }
>
>
>
> if mode == 1                                                then {
>
>
>
>        restore {g in G}                                      GBC[g];
>
>        restore {bi in BI}                                    BIBC[bi];
>
>        restore {bo in BO}                                    BOBC[bo];
>
>
>
>        option                                                solver couenne;
>
>        option                                                lp_solver
> cplex;
>
>        solve;
>
>
>
>        let                                                   mode := 2;
>
>        if solve_result_num < 100                             then {
>
>              let                                            submode := 999;
>
>              print
> '--------------------------------------OPTIMAL SOLUTION
> FOUND--------------------------------------';
>
>              display                                        Isc;
>
>              display                                        D;
>
>              display                                        OBJ2;
>
>              print
> '--------------------------------------------------------------------------------------------------';
>
>        }
>
> }
>
>
>
> }
>
> while                                                       mode < 4;
>
>
>
> With kind regards,
>
>
>
> Tom Van Acker
>
> --
> Tom Van Acker
> Researcher – University of Leuven (KU Leuven)
> Department Electrical Engineering (ESAT) - Research group Electrical Energy
> (ELECTA)
> Kasteelpark Arenberg 10 – 3001 Heverlee – Belgium
>
> WORK: +32 16 37 93 06
> GSM: +32 (0)478 771 361 (mobile)
> Email: Tom.VanAcker at esat.kuleuven.be
>
>
>
>
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