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

GMP::Instance::SetCallbackTime

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

Arguments

GMP

An element in AllGeneratedMathematicalPrograms.

callback

A reference to a procedure in the set AllIdentifiers.

Return Value

The procedure returns 1 on success, or 0 otherwise.

Note

  • 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, COPT, 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.

See also

The routines GMP::Instance::Generate, GMP::Instance::SetCallbackAddCut, GMP::Instance::SetCallbackAddLazyConstraint, GMP::Instance::SetCallbackBranch, GMP::Instance::SetCallbackCandidate, GMP::Instance::SetCallbackHeuristic, GMP::Instance::SetCallbackIncumbent and GMP::Instance::SetCallbackStatusChange.