Cplex 7.5 is a maintenance release only. There are no new or changed parameters.
The following parameters have been removed as of version 7.1:
Parameters nodefiledir and nodefilelim have been replaced by new parameters workdir and workmem.
Permits use of disk for temporary storage of the Barrier Cholesky factorization. This can allow solution of larger models on a given computer.
Specifies whether or not the original model should be compressed after presolve is performed.
Specifies the name of an existing directory into which Cplex may store temporary files. Used for MIP node files and by the new out-of-core Barrier capability.
Specifies an upper limit on the amount of main memory that Cplex can use for working files.
Optimality tolerance for the network simplex method.
Feasibility tolerance for the network simplex method.
Network simplex pricing algorithm.
This is now an upper limit on the size of the branch and cut tree. Formerly, it specified the maximum size in main memory.
Parameters can now be set interactively after interrupting Cplex with a Control-C.
Solution quality statistics available from Cplex can now be written to the GAMS listing file.
The GAMS license file now includes information on the various separately licensed Cplex options. The Cplex license manager is no longer used to control access to GAMS/Cplex.
This new Cplex parameter is now used to select the algorithm to be used for LP problems. The default LP method has been changed to dual simplex.
The default for this parameter has been changed to yes.
Possible values for this parameter now include auto which is the default. This is equivalent to no if names have been loaded into Cplex and yes if not.
The default for this parameter has been changed to automatic. As of Cplex 7.0, the automatic setting affects only the barrier method. It is equivalent to off for the other methods.
This new Cplex parameter determines whether primal reductions, dual reductions, or both, are performed during preprocessing.
This parameter is no longer available. Its purpose was to allow the use of presolve for the final LP of a MIP. As of Cplex 7.0, presolve is always used for the final LP.
This new Cplex parameter determines whether a switch of algorithms will be made when undoing perturbations and/or shifts that may occur during execution of the primal or dual simplex algorithms.
This new Cplex parameter is used to determine which crossover method to use at the end of a barrier run.
The default for this paramter is now automatic which provides the best performance for most models.
This parameter is no longer supported in GAMS/Cplex. Its functionality has been improved on, and replaced by, the periodic heuristic controlled by Cplex parameter heurfreq.
The default value for this parameter has been changed from no node file to node file in memory and compressed. This should have a minimal effect on speed with a reduction in memory usage when large trees are generated.
The default value for this parameter has been changed from 1e+75 to 128. This will cause a decrease in memory usage when large trees are generated.
This parameter has been removed. Use parameter barcrossalg instead.
This new Cplex parameter specifies whether feasibility or optimality should be emphasized as the algorithm proceeds.
This new Cplex parameter controls whether presolve will be performed at the nodes of the branch and bound tree.
This parameter has a new setting of 3 which performs additional analysis beyond levels 1 and 2.
This new Cplex parameter limits the number of passes that Cplex will perform when generating cutting planes on a MIP model.
This new Cplex parameter limits the number of constraints that can be aggregated for generating flow cover and mixed integer rounding cuts.
This new Cplex parameter determines whether or not flow path cuts should be generated for the problem.
This new Cplex parameter determines whether or not mixed integer rounding cuts should be generated for the problem.
This new Cplex parameter determines whether or not disjunctive cuts will be generated for the problem.
This new Cplex parameter limits the number of passes that Cplex will perform when generating Gomory cuts on a MIP model.
This new Cplex parameter limits the number of candidate variables that Cplex will examine when generating Gomory cuts on a MIP model.