CBC Options¶
ampl: option solver cbc; # change the solver
ampl: option cbc_options 'option1=value1 option2=value2'; # specify options
ampl: solve; # solve the problem
Solver options obtained with $ cbc -=.
CBCMP Optimizer Options for AMPL
--------------------------------------------
To set these options, assign a string specifying their values to the AMPL
option "cbcmp_options". For example:
ampl: option cbcmp_options 'mipgap=1e-6';
Options:
:cplexUse (cplexUse)
Whether to use Cplex!
off - Turn off
on - Turn on
:mixedIntegerRoundingCuts (mixedIntegerRoundingCuts)
Whether to use Mixed Integer Rounding cuts
off - disabled
on - enabled
root - enabled only on root node
ifmove - enabled in the tree if it moves the objective value
forceOn - enabled at every node
onglobal -
acc:sos2
Solver acceptance level for 'SOS2Constraint', default 2:
0 - Not accepted natively, automatic redefinition will be attempted
1 - Accepted but automatic redefinition will be used where possible
2 - Accepted natively and preferred
alg:basis (basis)
Whether to use or return a basis:
0 - No
1 - Use incoming basis (if provided)
2 - Return final basis
3 - Both (1 + 2 = default)
alg:perturbation (perturbation)
Whether to perturb the problem
off - Turn off
on - Turn on
alg:relax (relax)
0*/1: Whether to relax integrality of variables.
bar:bscale (bscale)
Whether to scale in barrier (and ordering speed)
off -
on -
off1 -
on1 -
off2 -
on2 -
bar:cholesky (cholesky)
Which cholesky algorithm
native -
dense -
fudgeLong_dummy -
wssmp_dummy -
UniversityOfFlorida_dummy -
Taucs_dummy -
Mumps_dummy -
Pardiso_dummy -
bar:crash (crash)
Whether to create basis for problem
off - Turn off
on - Turn on
bar:crossover (crossover)
Whether to get a basic solution with the simplex algorithm after the
barrier algorithm finished
on -
off -
maybe -
presolve -
bar:gammadelta (gamma(Delta))
Whether to regularize barrier
off -
on -
gamma -
delta -
onstrong -
gammastrong -
deltastrong -
bar:kkt (KKT)
Whether to use KKT factorization in barrier
off - Turn off
on - Turn on
cut:cliqueCuts (cliqueCuts)
Whether to use Clique cuts
off - disabled
on - enabled
root - enabled only on root node
ifmove - enabled in the tree if it moves the objective value
forceOn - enabled at every node
onglobal -
cut:cut (cutsOnOff)
Switches all cut generators on or off
off - disabled
on - enabled
root - enabled only on root node
ifmove - enabled in the tree if it moves the objective value
forceOn - enabled at every node
cut:flowcovercuts (flowCoverCuts)
Whether to use Flow Cover cuts
off - disabled
on - enabled
root - enabled only on root node
ifmove - enabled in the tree if it moves the objective value
forceOn - enabled at every node
onglobal -
cut:gmicuts (GMICuts)
Whether to use alternative Gomory cuts
off -
on -
root -
ifmove -
forceOn -
endonly -
long -
longroot -
longifmove -
forceLongOn -
longendonly -
cut:gomorycuts (gomoryCuts)
Whether to use Gomory cuts
off -
on -
root -
ifmove -
forceOn -
onglobal -
forceandglobal -
forceLongOn -
long -
cut:knapsackcuts (knapsackCuts)
Whether to use Knapsack cuts
off -
on -
root -
ifmove -
forceOn -
onglobal -
forceandglobal -
cut:lagomorycuts (lagomoryCuts)
Whether to use Lagrangean Gomory cuts
off -
endonlyroot -
endcleanroot -
root -
endonly -
endclean -
endboth -
onlyaswell -
cleanaswell -
bothaswell -
onlyinstead -
cleaninstead -
bothinstead -
onlyaswellroot -
cleanaswellroot -
bothaswellroot -
cut:latwomircuts (latwomirCuts)
Whether to use Lagrangean TwoMir cuts
off -
endonlyroot -
endcleanroot -
endbothroot -
endonly -
endclean -
endboth -
onlyaswell -
cleanaswell -
bothaswell -
onlyinstead -
cleaninstead -
bothinstead -
cut:liftandprojectcuts (liftAndProjectCuts)
Whether to use Lift and Project cuts
off - disabled
on - enabled
root - enabled only on root node
ifmove - enabled in the tree if it moves the objective value
forceOn - enabled at every node
cut:probingCuts (probingCuts)
Whether to use Probing cuts
off -
on -
root -
ifmove -
forceOn -
onglobal -
forceonglobal -
forceOnBut -
forceOnStrong -
forceOnButStrong -
strongRoot -
cut:reduce2andsplitcts (reduce2AndSplitCuts)
Whether to use Reduce-and-Split cuts - style 2
off -
on -
root -
longOn -
longRoot -
cut:reduceandsplitcuts (reduceAndSplitCuts)
Whether to use Reduce-and-Split cuts
off - disabled
on - enabled
root - enabled only on root node
ifmove - enabled in the tree if it moves the objective value
forceOn - enabled at every node
cut:residualcapacitycuts (residualCapacityCuts)
Whether to use Residual Capacity cuts
off - disabled
on - enabled
root - enabled only on root node
ifmove - enabled in the tree if it moves the objective value
forceOn - enabled at every node
cut:twomircuts (twoMirCuts)
Whether to use Two phase Mixed Integer Rounding cuts
off -
on -
root -
ifmove -
forceOn -
onglobal -
forceandglobal -
forceLongOn -
cut:zeroHalfCuts (zeroHalfCuts)
Whether to use zero half cuts
off - disabled
on - enabled
root - enabled only on root node
ifmove - enabled in the tree if it moves the objective value
forceOn - enabled at every node
onglobal -
cvt:bigM (cvt:bigm, cvt:mip:bigM, cvt:mip:bigm)
Default value of big-M for linearization of logical constraints. Not
used by default. Use with care (prefer tight bounds). Should be smaller
than (1.0 / [integrality tolerance])
cvt:mip:eps (cvt:cmp:eps)
Tolerance for strict comparison of continuous variables for MIP. Ensure
larger than the solver's feasibility tolerance.
cvt:plapprox:domain (plapprox:domain, plapproxdomain)
For piecewise-linear approximated functions, both arguments and result
are bounded to +-[pladomain]. Default 1e6.
cvt:plapprox:reltol (plapprox:reltol, plapproxreltol)
Relative tolerance for piecewise-linear approximation. Default 0.01.
cvt:pre:all
0/1*: Set to 0 to disable most presolve in the flat converter.
cvt:pre:eqbinary
0/1*: Preprocess reified equality comparison with a binary variable.
cvt:pre:eqresult
0/1*: Preprocess reified equality comparison's boolean result bounds.
cvt:quadcon (passquadcon)
0*/1: Multiply out and pass quadratic constraint terms to the solver,
vs. linear approximation.
cvt:quadobj (passquadobj)
0*/1: Multiply out and pass quadratic objective terms to the solver, vs.
linear approximation.
cvt:sos (sos)
0/1*: Whether to honor declared suffixes .sosno and .ref describing SOS
sets. Each distinct nonzero .sosno value designates an SOS set, of type
1 for positive .sosno values and of type 2 for negative values. The .ref
suffix contains corresponding reference values used to order the
variables.
cvt:sos2 (sos2)
0/1*: Whether to honor SOS2 constraints for nonconvex piecewise-linear
terms, using suffixes .sos and .sosref provided by AMPL.
double:allowableGap (allowableGap)
Stop when gap between best possible and best less than this (default 0).
double:artificialCost (artificialCost)
Costs >= this treated as artificials in feasibility pump (default 0).
double:cutoff (cutoff)
Bound on the objective value for all solutions (default 1e+50).
double:dextra3 (dextra3)
Extra double parameter 3 (default 0).
double:dextra4 (dextra4)
Extra double parameter 4 (default 0).
double:dextra5 (dextra5)
Extra double parameter 5 (default 0).
double:dualBound (dualBound)
Initially algorithm acts as if no gap between bounds exceeds this value
(default 1e+10).
double:dualTolerance (dualTolerance)
For an optimal solution no dual infeasibility may exceed this value
(default 1e-07).
double:fixOnDj (fixOnDj)
Try heuristic based on fixing variables with reduced costs greater than
this (default -1).
double:fractionforBAB (fractionforBAB)
Fraction in feasibility pump (default 0.5).
double:increment (increment)
A valid solution must be at least this much better than last integer
solution (default 1e-05).
double:infeasibilityWeight (infeasibilityWeight)
Each integer infeasibility is expected to cost this much (default 0).
double:integerTolerance (integerTolerance)
For a feasible solution no integer variable may be more than this away
from an integer value (default 1e-07).
double:objectiveScale (objectiveScale)
Scale factor to apply to objective (default 1).
double:preTolerance (preTolerance)
Tolerance to use in presolve (default 1e-08).
double:primalTolerance (primalTolerance)
For a feasible solution no primal infeasibility, i.e., constraint
violation, may exceed this value (default 1e-07).
double:primalWeight (primalWeight)
Initially algorithm acts as if it costs this much to be infeasible
(default 1e+10).
double:psi (psi)
Two-dimension pricing factor for Positive Edge criterion (default -0.5).
double:pumpCutoff (pumpCutoff)
Fake cutoff for use in feasibility pump (default 0).
double:pumpIncrement (pumpIncrement)
Fake increment for use in feasibility pump (default 0).
double:ratioGap (ratioGap)
Stop when gap between best possible and best known is less than this
fraction of larger of two (default 0).
double:reallyObjectiveScale (reallyObjectiveScale)
Scale factor to apply to objective in place (default 1).
double:rhsScale (rhsScale)
Scale factor to apply to rhs and bounds (default 1).
double:seconds (seconds)
maximum seconds (default 1e+08).
double:tightenFactor (tightenFactor)
Tighten bounds using this times largest activity at continuous solution
(default -1).
double:zeroTolerance (zeroTolerance)
Kill all coefficients whose absolute value is less than this value
(default 1e-20).
int:cppGenerate (cppGenerate)
Generates C++ code (default -1).
int:cutDepth (cutDepth)
Depth in tree at which to do cuts (default -1).
int:cutLength (cutLength)
Length of a cut (default -1).
int:decompose (decompose)
Whether to try decomposition (default 0).
int:denseThreshold (denseThreshold)
Threshold for using dense factorization (default -1).
int:depthMiniBab (depthMiniBab)
Depth at which to try mini branch-and-bound (default -1).
int:diveOpt (diveOpt)
Diving options (default -1).
int:diveSolves (diveSolves)
Diving solve option (default 100).
int:dualize (dualize)
Solves dual reformulation (default 3).
int:expensiveStrong (expensiveStrong)
Whether to do even more strong branching (default 0).
int:experiment (experiment)
Whether to use testing features (default 0).
int:extra1 (extra1)
Extra integer parameter 1 (default -1).
int:extra2 (extra2)
Extra integer parameter 2 (default -1).
int:extra3 (extra3)
Extra integer parameter 3 (default -1).
int:extra4 (extra4)
Extra integer parameter 4 (default -1).
int:extraVariables (extraVariables)
Allow creation of extra integer variables (default 0).
int:forceSolution (forceSolution)
Whether to use given solution as crash for BAB (default -1).
int:hOptions (hOptions)
Heuristic options (default 0).
int:hotStartMaxIts (hotStartMaxIts)
Maximum iterations on hot start (default 100).
int:idiotCrash (idiotCrash)
Whether to try idiot crash (default -1).
int:logLevel (logLevel)
Level of detail in Coin branch and Cut output (default 1).
int:maxFactor (maxFactor)
Maximum number of iterations between refactorizations (default 200).
int:maxIterations (maxIterations)
Maximum number of iterations before stopping (default 2147483647).
int:maxNodes (maxNodes)
Maximum number of nodes to do (default 2147483647).
int:maxSavedSolutions (maxSavedSolutions)
Maximum number of solutions to save (default -1).
int:maxSolutions (maxSolutions)
Maximum number of feasible solutions to get (default -1).
int:mipOptions (mipOptions)
Dubious options for mip (default 1057).
int:moreMipOptions (moreMipOptions)
More dubious options for mip (default -1).
int:moreSpecialOptions (moreSpecialOptions)
Yet more dubious options for Simplex - see ClpSimplex.hpp (default -1).
int:moreTune (moreTune)
Yet more dubious ideas for feasibility pump (default 0).
int:multipleRootPasses (multipleRootPasses)
Do multiple root passes to collect cuts and solutions (default 0).
int:numberAnalyze (numberAnalyze)
Number of analysis iterations (default -1).
int:outputFormat (outputFormat)
Which output format to use (default 2).
int:passCuts (passCuts)
Number of rounds that cut generators are applied in the root node
(default 20).
int:passFeasibilityPump (passFeasibilityPump)
How many passes to do in the Feasibility Pump heuristic (default 20).
int:passPresolve (passPresolve)
How many passes in presolve (default 5).
int:passTreeCuts (passTreeCuts)
Number of rounds that cut generators are applied in the tree (default
1).
int:pertValue (pertValue)
Method of perturbation (default 50).
int:pOptions (pOptions)
Dubious print options (default 0).
int:preOpt (preOpt)
Presolve options (default -1).
int:pumpTune (pumpTune)
Dubious ideas for feasibility pump (default 1003).
int:randomCbcSeed (randomCbcSeed)
Random seed for Cbc (default -1).
int:randomSeed (randomSeed)
Random seed for Clp (default 1234567).
int:slogLevel (slogLevel)
Level of detail in (LP) Solver output (default 1).
int:slowcutpasses (slowcutpasses)
Maximum number of rounds for slower cut generators (default 10).
int:slpValue (slpValue)
Number of slp passes before primal (default -1).
int:smallFactorization (smallFactorization)
Threshold for using small factorization (default -1).
int:specialOptions (specialOptions)
Dubious options for Simplex - see ClpSimplex.hpp (default -1).
int:sprintCrash (sprintCrash)
Whether to try sprint crash (default -1).
int:strategy (strategy)
Switches on groups of features (default 1).
int:strongBranching (strongBranching)
Number of variables to look at in strong branching (default 5).
int:substitution (substitution)
How long a column to substitute for in presolve (default 3).
int:testOsi (testOsi)
Test OsiObject stuff (default -1).
int:trustPseudoCosts (trustPseudoCosts)
Number of branches before we trust pseudocosts (default 5).
int:tunePreProcess (tunePreProcess)
Dubious tuning parameters for preprocessing (default -1).
int:verbose (verbose)
Switches on longer help on single ? (default 0).
int:vubheuristic (vubheuristic)
Type of VUB heuristic (default -1).
lim:time (timelim, timelimit)
Limit on solve time (in seconds; default: no limit).
lp:dualpivot (dualPivot)
Dual pivot choice algorithm
automatic -
dantzig -
partial -
steepest -
PEsteepest -
PEdantzig -
lp:pfi (PFI)
Whether to use Product Form of Inverse in simplex
off - Turn off
on - Turn on
lp:primalpivot (primalPivot)
Primal pivot choice algorithm
auto!matic -
exact -
dantzig -
partial -
steepest -
change -
sprint -
PEsteepest -
PEdantzig -
mip:combine2Solutions (combine2Solutions)
Whether to use crossover solution heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:combineSolutions (combineSolutions)
Whether to use combine solution heuristic
off -
on -
both -
before -
onquick -
bothquick -
beforequick -
mip:constraintfromCutoff (constraintfromCutoff)
Whether to use cutoff as constraint
off -
on -
variable -
forcevariable -
conflict -
mip:costStrategy (costStrategy)
How to use costs for branching priorities
off -
priorities -
columnOrder -
01first -
01last -
length -
singletons -
nonzero -
generalForce -
mip:dins (Dins)
Whether to try Distance Induced Neighborhood Search
off -
on -
both -
before -
often -
mip:divingcoefficient (DivingCoefficient)
Whether to try Coefficient diving heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:divingfractional (DivingFractional)
Whether to try Fractional diving heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:divingguided (DivingGuided)
Whether to try Guided diving heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:divinglinesearch (DivingLineSearch)
Whether to try Linesearch diving heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:divingpseudocost (DivingPseudoCost)
Whether to try Pseudocost diving heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:divingsome (DivingSome)
Whether to try Diving heuristics
off - disabled
on - use every node in the tree
both -
before -
mip:divingvectorlength (DivingVectorLength)
Whether to try Vectorlength diving heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:dwHeuristic (dwHeuristic)
Whether to try Dantzig Wolfe heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:feasibilitypumpfeasibilityPump
Whether to try the Feasibility Pump heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:greedyheuristic (greedyHeuristic)
Whether to use a greedy heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:heuristics (heuristicsOnOff)
Switches most primal heuristics on or off
off - Turn off
on - Turn on
mip:localtreesearch (localTreeSearch)
Whether to use local tree search when a solution is found
off - Turn off
on - Turn on
mip:naiveheuristics (naiveHeuristics)
Whether to try some stupid heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:nodestrategy (nodeStrategy)
What strategy to use to select the next node from the branch and cut
tree
hybrid -
fewest -
depth -
upfewest -
downfewest -
updepth -
downdepth -
mip:pivotandcomplement (pivotAndComplement)
Whether to try Pivot and Complement heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:pivotandfix (pivotAndFix)
Whether to try Pivot and Fix heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:proximitysearch (proximitySearch)
Whether to do proximity search heuristic
off -
on -
both -
before -
10 -
100 -
300 -
mip:randomizedrounding (randomizedRounding)
Whether to try randomized rounding heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:rens (Rens)
Whether to try Relaxation Enforced Neighborhood Search
off -
on -
both -
before -
200 -
1000 -
10000 -
dj -
djbefore -
usesolution -
mip:rins (Rins)
Whether to try Relaxed Induced Neighborhood Search
off -
on -
both -
before -
often -
mip:round (round)
Whether to round integer variables to integral values before returning
the solution, and whether to report that the solver returned noninteger
values for integer values: sum of
1 ==> Round nonintegral integer variables
2 ==> Modify solve_result
4 ==> Modify solve_message
Default = 0. Modifications that were or would be made are reported in
solve_result and solve_message only if the maximum deviation from
integrality exceeded mip:round_reptol.
mip:round_reptol (round_reptol)
Tolerance for reporting rounding of integer variables to integer values;
see "mip:round". Default = 1e-9.
mip:roundingheuristic (roundingHeuristic)
Whether to use simple (but effective) Rounding heuristic
off - disabled
on - use every node in the tree
both -
before -
mip:vndvariableneighborhoodsearch (VndVariableNeighborhoodSearch)
Whether to try Variable Neighborhood Search
off -
on -
both -
before -
intree -
obj:no (objno)
Objective to optimize:
0 - None
1 - First (default, if available)
2 - Second (if available), etc.
pre:autoScale
Whether to scale objective, rhs and bounds of problem if they look odd:
off - Turn off
on - Turn on
pre:biasLU
Whether factorization biased towards U:
UU -
UX -
LX -
LL -
pre:factorization (factorization)
Which factorization to use
normal -
dense -
simple -
osl -
pre:preprocess (preprocess)
Whether to use integer preprocessing
off -
on -
save -
equal -
sos -
trysos -
equalall -
strategy -
aggregate -
forcesos -
stopaftersaving -
pre:presolve (presolve)
Whether to presolve problem
on -
off -
more -
file -
pre:scaling (scaling)
Whether to scale problem
off -
equilibrium -
geometric -
automatic -
dynamic -
rowsonly -
pre:sparsefactor (sparseFactor)
Whether factorization treated as sparse
off - Turn off
on - Turn on
tech:debug (debug)
0*/1: whether to assist testing & debugging, e.g., by outputting
auxiliary information.
tech:exportfile (writeprob, writemodel)
Specifies the name of a file where to export the model before solving
it. This file name can have extension ".lp()", ".mps", etc. Default = ""
(don't export the model).
tech:justexportfile (justwriteprob, justwritemodel)
Specifies the name of a file where to export the model, do not solve
it.This file name can have extension ".lp()", ".mps", etc. Default = ""
(don't export the model).
tech:messages (messages)
Controls if Clpnnnn is printed
off - Turn off
on - Turn on
tech:optionfile (optionfile, option:file)
Name of solver option file. (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:outlev (outlev)
0*-4: Whether to write log lines (chatter) to stdout and to file.
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.
tech:writegraph (writegraph, exportgraph)
File to export conversion graph. Format: JSON Lines.