KB000025

AIMMS Knowledge Base Article – KB000025

 

MIP solver does not use initial solution

 

Summary

You can initialize the solution of a MIP when solving it with CPLEX, GUROBI, MOSEK or CBC.

Symptoms

You have an initial solution, but the solver does not seem to use it.

Cause

There are several causes for this problem:

  • The solver you use does not support the use of an initial solution. Currently only CPLEX, GUROBI, MOSEK and CBC support this.
  • The relevant option does not have the correct settings. 
  • You didn’t assign the initial solution to the variables.

Resolution

Make sure that you use a solver that supports the use of initial solutions (CPLEX, GUROBI, MOSEK or CBC). You can contact AIMMS if you have doubts.

Furthermore, make sure that the following option (Settings – Project Options…) is set:

CPLEX 9.1 and lower: Specific solvers – CPLEX X.X – MIP – MIP Start Values -> Yes
CPLEX 10.0 and higher: Specific solvers – CPLEX X.X – General – Advanced start -> Use advanced basis
GUROBI X.X: Specific solvers – GUROBI X.X – MIP – MIP Start -> Yes
MOSEK X.X: Specific solvers – MOSEK X.X – MIP – MIP Start -> Yes
CBC X.X: Specific solvers – CBC X.X – MIP – MIP Start -> On

Assign the values of your solution to the decision variables in your project and solve the model.

More information

For more information, please contact us at support@aimms.com.  

 

Last reviewed: 03-10-2011