[AMPL 2888] Branch and bound in CPLEX

[Saber Jalilzadeh-Galaeh]

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Hi all,

I am using AMPL/CPLEX and working on a MIP problem.
When the problem is solved, I have this message:

 

CPLEX 10.1.1: optimal integer solution; objective 198
4558 MIP simplex iterations
0 branch-and-bound nodes

 

But I want to solve my problem using B & B while it did not.

Somebody know why?

 

 

Saber

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[Ali Baharev]

Hello,

It probably means CPLEX found the solution on the root node, no
branching was necessary.

How do you know that your problem is not solved?

Ali

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[Paul A. Rubin]

On Oct 19, 8:06 am, Saber Jalilzadeh-Galaeh <sbr_612...@...>
wrote:

> Hi all,
> I am using AMPL/CPLEX and working on a MIP problem.
> When the problem is solved, I have this message:
>  
> CPLEX 10.1.1: optimal integer solution; objective 198
> 4558 MIP simplex iterations
> 0 branch-and-bound nodes
>  
> But I want to solve my problem using B & B while it did not.
> Somebody know why?

No branching was required.  CPLEX applied some cuts at the root node
and got an integer-feasible solution, which is optimal.  Or perhaps no
cuts were required -- if the LP relaxation gave an integer-feasible
solution, you would be done.

/Paul

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