Procedure GMP::Instance::SetCallbackIterations(GMP, callback, value)


The procedure GMP::Instance::SetCallbackIterations installs a callback procedure that is called after a specified number of iterations.

     GMP,            ! (input) a generated mathematical program
     callback,       ! (input) an AIMMS procedure
     [value]         ! (optional) number of iterations



An element in AllGeneratedMathematicalPrograms.


A reference to a procedure in the set AllIdentifiers.


A scalar value indicating after which number of iterations the callback procedure should be called. The default value is 0.

Return Value

The procedure returns 1 on success, or 0 otherwise.


  • The callback procedure should have exactly one argument; a scalar input element parameter into the set AllSolverSessions.

  • The CallbackIterations callback procedure should have a return value of

    • 0, if you want the solution process to stop, or

    • 1, if you want the solution process to continue.

  • To remove the callback the empty element should be used as the callback argument.

  • The number of iterations can also be set by the CallbackIterations suffix of the symbolic mathematical program, but will be overruled if the value is not equal to 0.

  • During a MIP solve, the iterations callback will be called irregularly by CPLEX, Gurobi and ODH-CPLEX (especially during the MIP phase).

  • The iterations callback will be called less often if CPLEX uses dynamic search as the MIP Search Strategy instead of branch-and-cut.

  • This procedure is not supported by COPT.