MPL for Windows Manual

Change CPLEX MIP Strategy2 Options

You can further change the MIP strategy options for CPLEX by choosing CPLEX parameters from the Options menu and then pressing the MIP Strategy2 tab. This will display the MIP strategy options for CPLEX in the dialog box as shown below:

Crossover Strategy

Chooses whether to employ Primal or Dual crossover when using Barrier for subproblems.

Use Advanced Starting Values

Used to indicate how the MIP advanced starting values are used at node 0. When set to On indicates that the values should be checked to see if they provide an integer feasible solution before starting optimization.

Reduced Cost Fixing

This option determines whether the reduced cost fixing strategy is to be applied. Reduce cost fixing sets integer values to bounds by considering reduced cost information at subproblems. This technique can significantly improve MIP performance, but can increase memory usage. By default, reduce cost fixing is On, but can be turned off as a memory-saving measure.

Scan For SOS

The Scan for SOS option, when set to On, initiates a scan for SOS Type 3 sets and invokes SOS Type 1 branching for these sets of variables. The automatic scan occurs immediately before CPLEX starts optimizing. An SOS Type 3 set results from each equality row with all binaries and +1 or -1 coefficients, and an RHS value of 1 - (number of -1 coefficients). SOS Type 3 sets are a special subset of SOS Type 1 sets which can be identified automatically by CPLEX. The default value for the Scan for SOS option is Off.

Rounding Heuristic

The Rounding heuristic option determines which heuristic should be applied to develop an initial integer solution.

Do not use heuristic	Do not use a rounding heuristic.

Automatic		The decision on using a heuristic will be 
			automatically determined by looking at the solution 
			to the initial relaxation of MIP.

Use heuristic		Rounding heuristic should be used.

Rounding Heuristic Frequency

The heuristic frequency options determines how often to apply the periodic heuristic. Setting the value to 0, the default, indicates that the periodic heuristic will not be applied at any nodes.

Start Algorithm

The Start algorithm option determines which LP algorithm should be used to solve the initial relaxation of the MIP.

Primal simplex		Use primal simplex (default).

Dual simplex		Use dual simplex.

Network simplex		Use network simplex.

Barrier w/crossover	Use barrier with crossover.

Dual/Barrier		Dual simplex to iteration limit, then barrier.

Barrier w/o crossover	Use barrier without crossover.

Sub Algorithm

The sub algorithm option sets the algorithm to be used on subproblems.

Primal simplex		Use primal simplex.

Dual simplex		Use dual simplex (default).

Network/Dual		Use network optimizer followed by dual simplex.

Barrier w/crossover	Use barrier with crossover.

Dual/Barrier		Use dual simplex to iteration limit, then barrier.

Barrier w/o crossover	Use barrier without crossover.