MIP Search Strategy

Type : Selection

Range : The settings listed below

Default : Automatic

This option sets the search strategy for a mixed integer program (MIP). Possible values are:

  • Automatic

  • Apply branch-and-cut

  • Apply dynamic search

For many models, dynamic search finds feasible and optimal solutions more quickly than the conventional branch-and-cut algorithm.

An important drawback of the dynamic search algorithm is that it cannot be used in combination with some callbacks! The branch, candidate, cut, heuristic callback procedures will not be executed if ‘Apply dynamic search’ is chosen. However, the callback procedures for incumbent, iterations and status change are still executed.

By default, CPLEX chooses whether to apply dynamic search or conventional branch-and-cut based on characteristics of the model and the presence (or absence) of callbacks. If a callback procedure is present then CPLEX will choose the conventional branch-and-cut if the value of this option is ‘Automatic’.

If the value of this option equals ‘Apply branch-and-cut’ then CPLEX will use only 1 thread if the option Global Thread Limit equals its default value of 0. To let CPLEX use multiple threads you have to set the Global Thread Limit to a value strictly larger than 1.

Note

  • You might want to decrease the value of the general solvers option Progress Time Interval if the progress window is no longer updated while solving your MIP model.

  • If dynamic search is used then AIMMS might become less responsive especially while solving the root node of the branch-and-bound tree.

  • The iterations callback procedure (if any) will be called less frequently in case dynamic search is used.

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