Re: [Help-glpk] Complexity of MILP

[Jeffrey Kantor]

Hi Esma,

Since this is an MILP, it's likely that the execution time is dominated by the branch and bound search for an integer optimal solution. Branching, and deciding which branches to search first, depend on the values of solutions at intermediate nodes in the search.  There can be a large change in execution time due to even small changes in parameter values or problem structure. So what you observed is not unusual.

How many integer variables were in these different problems?

On Tue, Sep 18, 2012 at 5:23 AM, esma mehiaoui <address@hidden> wrote:

Hello everyone,

 

I am befog in front of the execution times that i get when i run my MILP formulation.

 

For instance:

 

When i run the program with 3581 constraints and 1440 variables i get 9.87 sec for the response time.

 

When i run the program with 5482 constraints and 2080 variables i get 42.91 sec as execution time.

 

And when i run the program with 7383 constraints and 2720 variables i get 13.89 sec.

 

Could someone help me to find an explanation ?

 

Kind regards

 

Asma

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