Procedure GMP::Instance::SetCallbackTime(GMP, callback)


The procedure GMP::Instance::SetCallbackTime installs a callback procedure that is called after a specified number of (elapsed) seconds. By default this callback procedure is called every two seconds.

     GMP,            ! (input) a generated mathematical program
     callback        ! (input) an AIMMS procedure


An element in AllGeneratedMathematicalPrograms.
A reference to a procedure in the set AllIdentifiers.

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 CallbackTime 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 CallbackTime callback procedure is supported by CPLEX, GUROBI, CBC, ODH-CPLEX, XA, CP OPTIMIZER, CONOPT, KNITRO, SNOPT and IPOPT.
  • The number of (elapsed) seconds is determined by the general solvers option Progress Time Interval. This option also specifies the interval for updating the Progress Window during a solve. As a consequence, the information passed to this callback procedure will be the same as the information displayed in the Progress Window (except for small differences for the solving time).
  • The time callback will be called less often if CPLEX uses dynamic search as the MIP Search Strategy instead of branch-and-cut. In that case the interval between two successive calls might sometimes be larger than the interval as specified by the option Progress Time Interval.