# ILOGCP Options¶

```
ampl: option solver ilogcp; # change the solver
ampl: option ilogcp_options 'option1=value1 option2=value2'; # specify options
ampl: solve; # solve the problem
```

Solver options obtained with `$ ilogcp -=`

.

```
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.
cppresolve
0 or 1 (default 1): Whether to activate presolve on the CP optimizer.
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:
low
basic
medium
extended
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:
auto
off
on
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:
quiet
terse
normal
verbose
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.
multipointnumberofsearchpoints
Number of solutions for the multi-point search algorithm. Default = 30.
obj:multi (multiobj)
0*/1: 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.
obj:no (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".
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
iterativediving
The default value is "auto".
sol:count (countsolutions)
0*/1: Whether to count the number of solutions and return it in the
".nsol" problem suffix.
sol:stub (solstub, 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".
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.
tech:debug (debug)
0*/1: whether to assist testing & debugging, e.g., by outputting
auxiliary information.
tech:optionfile (optionfile, option:file)
Name of solver option file to read (surrounded by 'single' or "double"
quotes if the name contains blanks). Lines that start with # are
ignored. Otherwise, each nonempty line should contain "name=value".
tech:timing (timing)
0*/1: Whether to display timings for the run.
tech:version (version)
Single-word phrase: report version details before solving the problem.
tech:wantsol (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.
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:
cputime
elapsedtime
The default value is "cputime".
usenumberof
0 or 1 (default 1): Whether to aggregate "numberof" expressions by use
of "IloDistribute" constraints.
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".
```