IBM ILOG CPLEX CP Optimizer Options for AMPL
To set these options, assign a string specifying their values to the AMPL option ilogcp_options. For example:
ampl: option ilogcp_options 'optimalitytolerance=1e-6 searchtype=restart';
Options
- alldiffinferencelevel
Inference level for alldiff constraints. Possible values:
- default
- low
- basic
- medium
- extended
The default value is default, which allows the inference strength of all alldiff constraints to be controlled via defaultinferencelevel.
- branchlimit
- Limit on the number of branches made before terminating a search. Default = no limit.
- choicepointlimit
- Limit on the number of choice points created before terminating a search. Default = no limit.
- constraintaggregation
- 0 or 1 (default 1): Whether to aggregate basic constraints.
- countsolutions
- 0 or 1 (default 0): Whether to count the number of solutions and return it in the .nsol problem suffix.
- debugexpr
- 0 or 1 (default 0): Whether to print debugging information for expression trees.
- defaultinferencelevel
Inference level for constraints that have inference level set to default. Possible values:
The default value is basic.
- distributeinferencelevel
Inference level for aggregated numberof (IloDistribute) constraints. Possible values:
- default
- low
- basic
- medium
- extended
The default value is default, which allows the inference strength of all aggregated numberof constraints to be controlled via defaultinferencelevel.
- dumpfile
- Specifies the name of a file where to dump the model before solving it. This file name must have extension .cpo. Default = "" (don’t dump the model).
- dynamicprobing
Use probing during search. Possible values:
The default value is auto.
- dynamicprobingstrength
- Effort dedicated to dynamic probing as a factor of the total search effort. Default = 0.03.
- elementinferencelevel
Inference level for element (IloElement) constraints. Possible values:
- default
- low
- basic
- medium
- extended
The default value is default, which allows the inference strength of all element constraints to be controlled via defaultinferencelevel.
- exportfile
- Specifies the name of a file where to export the model before solving it. This file name must have extension .cpo. Default = "" (don’t export the model).
- faillimit
- Limit on the number of failures allowed before terminating a search. Default = no limit.
- failuredirectedsearchemphasis
- Specifies the number of workers that use failure-directed search once it has started. The value does not have to be integer. For example, value 1.5 means that first worker spends 100% of the time by failure-directed search, second worker 50% and remaining workers 0%. Default = auto (depends on actual performance of the failure-directed search).
- logperiod
- Specifies how often the information in the search log is displayed.
- logverbosity
Verbosity of the search log. Possible values:
The default value is quiet.
- mipdisplay
Frequency of displaying branch-and-bound information (for optimizing integer variables):
0 (default) – never
1 – each integer feasible solution
2 – every mipinterval nodes
3 – every mipinterval nodes plus information on LP relaxations (as controlled by display)
4 – same as 2, plus LP relaxation info.
5 – same as 2, plus LP subproblem info.
- mipinterval
- Frequency of node logging for mipdisplay 2 or 3. Default = 0.
- multiobj
- 0 or 1 (default 0): Whether to use multi-objective optimization. If set to 1 multi-objective optimization is performed using lexicographic method with the first objective treated as the most important, then the second objective and so on.
- multipointnumberofsearchpoints
- Number of solutions for the multi-point search algorithm. Default = 30.
- objno
Objective to optimize:
0 – none
1 – first (default, if available)
2 – second (if available), etc.
- optimalitytolerance
- Absolute tolerance on the objective value. Default = 0.
- optimizer
Specifies which optimizer to use. Possible values:
auto | CP Optimizer if the problem has nonlinear objective/constraints or logical constraints, CPLEX otherwise |
cp | CP Optimizer |
cplex | CPLEX Optimizer |
The default value is auto.
- outlev
- Synonym for logverbosity.
- propagationlog
Level of propagation trace reporting. Possible values:
The default value is quiet.
- randomseed
- Seed for the random number generator. Default = 0.
- relativeoptimalitytolerance
- Relative tolerance on the objective value. Default = 1e-4.
- restartfaillimit
- Number of failures allowed before restarting search. Default = 100.
- restartgrowthfactor
- Increase of the number of allowed failures before restarting search. Default = 1.05.
- searchtype
Type of search used for solving a problem. Possible values:
- auto
- depthfirst
- restart
- multipoint
The default value is auto.
- solutionlimit
- Limit on the number of feasible solutions found before terminating a search. Leaving the solution limit unspecified will make the optimizer search for an optimal solution if there is an objective function or for a feasible solution otherwise.
- solutionstub
- Stub for solution files. If solutionstub is specified, found solutions are written to files (solutionstub & '1' & '.sol') … (solutionstub & Current.nsol & '.sol'), where Current.nsol holds the number of returned solutions. That is, file names are obtained by appending 1, 2, … Current.nsol to solutionstub.
- temporalrelaxation
- 0 or 1 (default 1): Whether to use temporal relaxation.
- timelimit
- Limit on the CPU time spent solving before terminating a search. Default = no limit.
- timemode
Specifies how the time is measured in CP Optimizer. Possible values:
The default value is cputime.
- timing
- 0 or 1 (default 0): Whether to display timings for the run.
- usenumberof
- 0 or 1 (default 1): Whether to aggregate numberof expressions by use of IloDistribute constraints.
- version
- Single-word phrase: report version details before solving the problem.
- wantsol
In a stand-alone invocation (no -AMPL on the command line), what solution information to write. Sum of
1 – write .sol file
2 – primal variables to stdout
4 – dual variables to stdout
8 – suppress solution message
- warninglevel
- Specifies the highest warning level to be displayed, all warnings higher than this level are masked. CP Optimizer warning levels run from 1 to 4, so setting this option to 0 turns off all warnings. Warnings issued may indicate potential errors or inefficiencies in your model. Default = 2.
- workers
- Number of workers to run in parallel to solve a problem. In addition to numeric values this option accepts the value auto since CP Optimizer version 12.3. Default = auto.