ILOG CPLEX users can vary parameters by means of the set command. This command is used to set ILOG CPLEX parameters to values different from their default values. The procedure for setting a parameter is similar to that of other commands. Commands can be carried out incrementally or all in one line from the ILOG CPLEX prompt. Whenever a parameter is set to a new value, ILOG CPLEX inserts a comment in the log file that indicates the new value.

To see the parameters that can be changed, type:

set

The parameters that can be changed are displayed with a prompt, like this:

Available Parameters: advance set indicator for advanced starting information barrier set parameters for barrier optimization clocktype set type of clock used to measure time defaults set all parameter values to defaults logfile set file to which results are printed lpmethod set method for linear optimization mip set parameters for mixed integer optimization network set parameters for network optimizations output set extent and destinations of outputs preprocessing set parameters for preprocessing qpmethod set method for quadratic optimization read set problem read parameters sifting set parameters for sifting optimization simplex set parameters for primal and dual simplex optimizations threads set default parallel thread count timelimit set time limit in seconds workdir set directory for working files workmem set memory available for working storage (in megabytes) Parameter to set:

If you press the <return> key without entering a parameter name, the following message is displayed:

No parameters changed.

Resetting Defaults

After making parameter changes, it is possible to reset all parameters to default values by issuing one command:

set defaults

This resets all parameters to their default values, except for the name of the log file.

The general syntax for the set command is:

set parameter option new_value

The current values of the parameters can be displayed with the command:

display settings all

A list of parameters with settings that differ from the default values can be displayed with the command:

display settings changed

For a description of all parameters and their default values, see the Parameter Table in the ILOG CPLEX Reference Manual. For examples of how to set parameters, see the ILOG CPLEX User's Manual.

ILOG CPLEX also accepts customized system parameter settings via a parameter specification file. See the ILOG CPLEX User's Manual for a description of the parameter specification file and its use.