[Couenne] Couenne Result

[Stefan Vigerske]

Hi,

Couenne can only minimize, so I guess the AMPL link reformulates your 
maximization problem as minimization.
The best possible and best objective that Couenne report are negative, 
with the best possible not greater but lower than the best objective.

Stefan

On 10/18/2014 10:49 PM, Priscilla Lusie wrote:
> Hi,
> I'm having a problem running Couenne for a non linear problem. It is
> printing the 'best possible' value greater than the 'best objective' but
> comparing to the result of others solvers, the 'best objective' is wrong.
> The correct value is one of the 'best possible' value found.
> The optimal value is 38291,70938 (found with another solvers). When I run
> display Profit (objective function), Couenne prints the correct value
> (38291). What's wrong?
> The couenne result is:
> Cbc0010I After 5600 nodes, 195 on tree, -26661.508 best solution, best
> possible -39139.591 (86.86 seconds)
> Cbc0010I After 5700 nodes, 184 on tree, -26661.508 best solution, best
> possible -38988.877 (86.96 seconds)
> Cbc0010I After 5800 nodes, 165 on tree, -26661.508 best solution, best
> possible -38773.25 (87.05 seconds)
> Cbc0010I After 5900 nodes, 137 on tree, -26661.508 best solution, best
> possible -38501.2 (87.15 seconds)
> Cbc0010I After 6000 nodes, 89 on tree, -26661.508 best solution, best
> possible -38094.493 (87.21 seconds)
> Cbc0010I After 6100 nodes, 39 on tree, -26661.508 best solution, best
> possible -34536.558 (87.25 seconds)
> Cbc0001I Search completed - best objective -26661.50836015483, took 57960
> iterations and 6178 nodes (87.27 seconds)
> Cbc0035I Maximum depth 86, 0 variables fixed on reduced cost
>          "Finished"
>
> couenne: Optimal
>
> ampl: display Profit;
> Profit = 38291.9
>
>
> Thank's,
> Priscilla Lusie
>
>
>
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