Originally posted by: SX1E_esma_sema

Hi all,

I am reading that within CPLEX we are able to assign priorities to variables for branching but i do not see how to do it in the interactive optimizer. For instance, my problem consists of two set of binary variables Ai and Bj for all i=1..n and j=1..m. I would like to give higher priority for all variables A and lower ones for B. Is that possible ? and how to specify the priorities, in a file ?

Best regards

Sema 

The easiest thing probably is to have the interactive create an order file and then look at that file. To create an order file in the interactive do

CPLEX> read mip.lp
CPLEX> set mip order 1
CPLEX> write order.ord

This creates a priority order in file order.ord. The file looks somewhat like this:

NAME          mip.lp   Priority Order
    x1                          182
    x2                            1
    x3                           61
    x4                           59
    x5                           19

In the column you have the variable names, in the right column are the priorities for the variables.

To load the order from a file just do

CPLEX> read order.ord

Note that the variable names in the order file and the currently loaded problem must match.

Originally posted by: SX1E_esma_sema

Thank you very much