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lp_get(++ParamName, ?Value)

Obtain the value of a global parameter for the external solver.
ParamName
Atom
Value
Variable, integer, float or atom

Calling Modes

Description

The external solvers have a number of global (i.e. not specific to a particular problem) parameters that affect the way they work. These can be queried using this predicate.

The Value returned is either an integer, float or atom, depending on the parameter. Refer to the solver documentation for details. The names of the parameters are derived from the names of the parameters in the external solver. For CPLEX, take the parameter name from the CPLEX manual (or cplex.h), remove the CPX_PARAM_ prefix and convert the rest to lower case, e.g. 

        CPX_PARAM_NODELIM becomes nodelim.
For XPRESS-MP, take the parameter name from the manual (or xpresso.h), remove the N_ prefix (if present) and convert the rest to lower case, e.g. 
	MAXNOD or N_MAXNOD becomes maxnod.
The following parameter names are additional aliases that work for either solver:
crash
CPX_PARAM_CRAIND (CPLEX) or N_ICRASH (XPRESS-MP) -integer
feasibility_tol
CPX_PARAM_EPRHS (CPLEX) or N_ZTOLZE (XPRESS-MP) - float
integrality
CPX_PARAM_EPINT (CPLEX) or N_ZTOLIS (XPRESS-MP) - float
iteration_limit
CPX_PARAM_ITLIM (CPLEX) or N_ITRLIM (XPRESS-MP) -integer
mip_display
CPX_PARAM_MIPDISPLAY (CPLEX) or N_IFMSG (XPRESS-MP) -integer
mip_interval
CPX_PARAM_MIPINTERVAL (CPLEX) or N_ITRLOG (XPRESS-MP) -integer
node_limit
CPX_PARAM_NODELIM (CPLEX) or N_MAXNOD (XPRESS-MP) -integer
objdifference
CPX_PARAM_OBJDIF (CPLEX) or N_ADDCUT (XPRESS-MP) - float
refactor
CPX_PARAM_REINV (CPLEX) or N_INVFRQ (XPRESS-MP) -integer
scrind
CPX_PARAM_SCRIND (CPLEX) or N_PRTMSG (XPRESS-MP) -integer
subalgorithm
CPX_PARAM_SUBALG (CPLEX) or N_IALG (XPRESS-MP) - integer
In addition, the following pseudo-parameters are supported
optimizer
Returns the name of the external solver, currently 'cplex' or 'xpress'.
optimizer_version
Returns an integer derived from the version of the external solver.
presolve
Returns the default presolve setting for solver setup, i.e. the presolve setting that a solver state would be given if it was not directly specified during setup in lp_setup or lp_demon_setup. The value is 1 if the default is to have presolve on, and 0 if off. Note that this is a change from previous versions of eplex, where this parameter is directly connected to the external solver's own global presolve setting.

See Also

lp_set / 2