ILOG CPLEX 11.0 Parameters Reference Manual > > Alphabetic List of Parameters > MIP emphasis switch

C Name

CPX_PARAM_MIPEMPHASIS

C++ Name

MIPEmphasis

Java Name

MIPEmphasis

.NET Name

MIPEmphasis

InteractiveOptimizer

emphasis mip

Identifier

2058

Description

Controls trade-offs between speed, feasibility, optimality, and moving bounds in MIP.

With the default setting of BALANCED, CPLEX works toward a rapid proof of an optimal solution, but balances that with effort toward finding high quality feasible solutions early in the optimization.

When this parameter is set to FEASIBILITY, CPLEX frequently will generate more feasible solutions as it optimizes the problem, at some sacrifice in the speed to the proof of optimality.

When set to OPTIMALITY, less effort may be applied to finding feasible solutions early.

With the setting BESTBOUND, even greater emphasis is placed on proving optimality through moving the best bound value, so that the detection of feasible solutions along the way becomes almost incidental.

When the parameter is set to HIDDENFEAS, the MIP optimizer works hard to find high quality feasible solutions that are otherwise very difficult to find, so consider this setting when the FEASIBILITY setting has difficulty finding solutions of acceptable quality.

Values

Value 
Symbol 
Meaning 
CPX_MIPEMPHASIS_BALANCED 
Balance optimality and feasibility; default 
CPX_MIPEMPHASIS_FEASIBILITY 
Emphasize feasibility over optimality 
CPX_MIPEMPHASIS_OPTIMALITY 
Emphasize optimality over feasibility  
CPX_MIPEMPHASIS_BESTBOUND 
Emphasize moving best bound  
CPX_MIPEMPHASIS_HIDDENFEAS 
Emphasize finding hidden feasible solutions