SCIP Options#
ampl: option solver scip; # change the solver
ampl: option scip_options 'option1=value1 option2=value2'; # specify options
ampl: solve; # solve the problem
Solver options obtained with $ scip -=.
SCIP Optimizer Options for AMPL
--------------------------------------------
To set these options, assign a string specifying their values to the AMPL
option "scip_options". For example:
ampl: option scip_options 'mipgap=1e-6';
Options:
acc:_all
Solver acceptance level for all constraints and expressions. Value
meaning: as described in the specific acc:... options.
Can be useful to disable all reformulations (acc:_all=2), or force
linearization (acc:_all=0.)
acc:_expr
Solver acceptance level for all expressions, default 1:
0 - Not accepted, all expressions will be treated as flat constraints,
or redefined
1 - Accepted. See the individual acc:... options
acc:abs
Solver acceptance level for 'AbsConstraint' as flat constraint, 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
acc:and (acc:forall)
Solver acceptance level for 'AndConstraint' as flat constraint, default
1:
0 - Not accepted natively, automatic redefinition will be attempted
1 - Accepted but automatic redefinition will be used where possible
2 - Accepted natively and preferred
acc:cos
Solver acceptance level for 'CosConstraint' as flat constraint, default
1:
0 - Not accepted natively, automatic redefinition will be attempted
1 - Accepted but automatic redefinition will be used where possible
2 - Accepted natively and preferred
acc:exp
Solver acceptance level for 'ExpConstraint' as either constraint or
expression, default 4:
0 - Not accepted natively, automatic redefinition will be attempted
1 - Accepted as constraint but automatic redefinition will be used
where possible
2 - Accepted as constraint natively and preferred
3 - Accepted as expression but automatic redefinition will be used
where possible
4 - Accepted as expression natively and preferred
acc:indeq (acc:indlineq)
Solver acceptance level for 'IndicatorConstraintLinEQ' as flat
constraint, default 1:
0 - Not accepted natively, automatic redefinition will be attempted
1 - Accepted but automatic redefinition will be used where possible
2 - Accepted natively and preferred
acc:indge (acc:indlinge)
Solver acceptance level for 'IndicatorConstraintLinGE' as flat
constraint, default 1:
0 - Not accepted natively, automatic redefinition will be attempted
1 - Accepted but automatic redefinition will be used where possible
2 - Accepted natively and preferred
acc:indle (acc:indlinle)
Solver acceptance level for 'IndicatorConstraintLinLE' as flat
constraint, default 1:
0 - Not accepted natively, automatic redefinition will be attempted
1 - Accepted but automatic redefinition will be used where possible
2 - Accepted natively and preferred
acc:lineq
Solver acceptance level for 'LinConEQ' as flat constraint, 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
acc:linge
Solver acceptance level for 'LinConGE' as flat constraint, 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
acc:linle
Solver acceptance level for 'LinConLE' as flat constraint, 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
acc:linrange (acc:linrng)
Solver acceptance level for 'LinConRange' as flat constraint, 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
acc:log
Solver acceptance level for 'LogConstraint' as flat constraint, 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
acc:or (acc:exists)
Solver acceptance level for 'OrConstraint' as flat constraint, 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
acc:pow
Solver acceptance level for 'PowConstraint' as flat constraint, 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
acc:quadcone
Solver acceptance level for 'QuadraticConeConstraint' as flat
constraint, default 1:
0 - Not accepted natively, automatic redefinition will be attempted
1 - Accepted but automatic redefinition will be used where possible
2 - Accepted natively and preferred
acc:quadeq
Solver acceptance level for 'QuadConEQ' as flat constraint, 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
acc:quadge
Solver acceptance level for 'QuadConGE' as flat constraint, 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
acc:quadle
Solver acceptance level for 'QuadConLE' as flat constraint, 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
acc:quadrange (acc:quadrng)
Solver acceptance level for 'QuadConRange' as flat constraint, 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
acc:sin
Solver acceptance level for 'SinConstraint' as flat constraint, 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
acc:sos1
Solver acceptance level for 'SOS1Constraint' as flat constraint, 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
acc:sos2
Solver acceptance level for 'SOS2Constraint' as flat constraint, default
1:
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:concurrent (concurrent)
0/1: whether to solve the problem using concurrent solvers
0 - No concurrent solvers are used to solve the problem (default)
1 - Concurrent solvers are used to solve the problem.
alg:method (method, lpmethod)
LP algorithm for solving initial LP relaxations:
s - automatic simplex (default)
p - primal simplex
d - dual simplex
b - barrier
c - barrier with crossover
alg:relax (relax)
0*/1: Whether to relax integrality of variables.
alg:remethod (remethod, relpmethod)
LP algorithm for resolving LP relaxations if a starting basis exists:
s - automatic simplex (default)
p - primal simplex
d - dual simplex
b - barrier
c - barrier with crossover
branch:preferbinary (preferbinary)
0/1: whether branching on binary variables should be preferred
0 - Binary variables should not be preferred on branching (default)
1 - Binary variables should be preferred on branching.
cut:dircutoffdistweight (dircutoffdistweight)
Weight of directed cutoff distance in cut score calculation (default:
0.0)
cut:efficacyweight (efficacyweight)
Weight of efficacy in cut score calculation (default: 1.0)
cut:intsupportweight (intsupportweight)
Weight of integral support in cut score calculation (default: 0.1)
cut:maxcuts (maxcuts)
Maximal number of cuts separated per separation round (0: disable local
separation; default: 100)
cut:maxcutsroot (maxcutsroot)
Maximal number of separated cuts at the root node (0: disable root node
separation; default: 5000)
cut:maxrounds
Maximal number of separation rounds per node (default: -1: unlimited)
cut:maxroundsroot
Maximal number of separation rounds in the root node (default: -1:
unlimited)
cut:maxstallrounds
Maximal number of consecutive separation rounds without objective or
integrality improvement in local nodes (-1: no additional restriction;
default: 1)
cut:maxstallroundsroot
Maximal number of consecutive separation rounds without objective or
integrality improvement in the root node (-1: no additional restriction;
default: 10)
cut:minactivityquot
Minimum cut activity quotient to convert cuts into constraints during a
restart (0.0: all cuts are converted; default: 0.8)
cut:minefficacy
Minimal efficacy for a cut to enter the LP (default: 0.0001)
cut:minefficacyroot
Minimal efficacy for a cut to enter the LP in the root node (default:
0.0001)
cut:minortho (minortho)
Minimal orthogonality for a cut to enter the LP (default: 0.9)
cut:minorthoroot (minorthoroot)
Minimal orthogonality for a cut to enter the LP in the root node
(default: 0.1)
cut:objparalweight (objparalweight)
Weight of objective parallelism in cut score calculation (default: 0.1)
cut:poolfreq
Separation frequency for the global cut pool (-1: disable global cut
pool; 0: only separate pool at the root; default: 10)
cut:settings
0/1/2/3: sets cuts settings
0 - Sets cuts default (default)
1 - Sets cuts aggressive
2 - Sets cuts fast
3 - Sets cuts off.
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:expcones (expcones)
0*/1: Recognize exponential cones.
cvt:mip:eps (cvt:cmp:eps, cmp:eps)
Tolerance for strict comparison of continuous variables for MIP. Applies
to <, >, and != operators. Also applies to negation of conditional
comparisons: b==1 <==> x<=5 means that with b==0, x>=5+eps. Default:
1e-4.
cvt:names (names, modelnames)
Whether to read or generate variable / constraint / objective names:
0 - No names
1 - (Default) Only provide names if at least one of .col / .row name
files was written by AMPL (AMPL: `option [<solver>_]auxfiles rc;`)
2 - Read names from AMPL, but create generic names if not provided
3 - Create generic names.
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:pre:unnest
0/1*: Inline nested expressions, currently Ands/Ors.
cvt:prod (cvt:pre:prod)
Product preprocessing flags. Sum of a subset of the following bits:
1 - Quadratize higher-order products in the following order: integer
terms first, then real-valued ones; in each group, smaller-range terms
first.
2 - Logicalize products of 2 binary terms. Logicalizing means that the
product is converted to a conjunction. If the solver does not support it
natively (see acc:and), the conjunction is linearized.
4 - Logicalize products of >=3 binary terms.
Default: 1+4. That is, 2-term binary products which are not part of a
higher-order binary product, are not logicalized by default.
Bits 2 or 4 imply bit 1.
cvt:quadcon (passquadcon)
Convenience option. Set to 0 to disable quadratic constraints. Synonym
for acc:quad..=0. Currently this disables out-multiplication of
quadratic terms, then they are linearized.
cvt:quadobj (passquadobj)
0*/1: Multiply out and pass quadratic objective terms to the solver, vs.
linear approximation.
cvt:socp (socpmode, socp)
Second-Order Cone recognition mode:
0 - Do not recognize SOCP forms
1 - Recognize from non-quadratic expressions only (sqrt, abs)
2 - Recognize from quadratic and non-quadratic SOCP forms. Helpful if
the solver does not recognize non-standard forms
Recognized SOCP forms can be further converted to (SOCP-standardized)
quadratic constraints, see cvt:socp2qc. Default: 2.
cvt:socp2qc (socp2qcmode, socp2qc)
Mode to convert recognized SOCP forms to SOCP-standardized quadratic
constraints:
0 - Do not convert
1 - Convert if no other cone types found, and not all original
quadratics could be recognized as SOC, in particular if the
objective is quadratic
2 - Always convert
Such conversion can be necessary if the solver does not accept a mix of
conic and quadratic constraints/objectives. Default: 1.
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.
cvt:uenc:negctx:max (uenc:negctx:max, uenc:negctx)
If cvt:uenc:ratio applies, max number of constants in comparisons
x==const in negative context (equivalently, x!=const in positive
context) to skip UEnc(x). Default 1.
cvt:uenc:ratio (uenc:ratio)
Min ratio (ub-lb)/Nvalues to skip unary encoding for a variable x, where
Nvalues is the number of constants used in conditional comparisons
x==const. Instead, indicator constraints (or big-Ms) are used, if
uenc:negctx also applies. Default 0.
est:completiontype
Approximation of search tree completion:
a - auto (default)
g - gap
w - tree weight
m - monotone regression
r - regression forest
s - ssg
est:method
Tree size estimation method:
c - completion
e - ensemble
g - time series forecasts on either gap
l - leaf frequency
o - open nodes
w - tree weight (default)
s - ssg
t - tree profile
b - wbe
heu:settings
0/1/2/3: sets heuristics settings
0 - Sets heuristics default (default)
1 - Sets heuristics aggressive
2 - Sets heuristics fast
3 - Sets heuristics off.
lim:absgap (absgap, mip:gapabs, mipgapabs)
Solving stops, if the absolute gap = |primalbound - dualbound| is below
the given value (default: 0.0)
lim:autorestartnodes
If solve exceeds this number of nodes for the first time, an automatic
restart is triggered (default: -1: no automatic restart)
lim:bestsol
Solving stops, if the given number of solution improvements were found
(default: -1: no limit)
lim:gap (gap, mip:gap, mipgap)
Solving stops, if the relative gap = |primal -
dual|/MIN(|dual|,|primal|) is below the given value, the gap is
'Infinity', if primal and dual bound have opposite signs (default: 0.0)
lim:maxorigsol
Maximal number of solutions candidates to store in the solution storage
of the original problem (default: 10)
lim:maxsol
Maximal number of solutions to store in the solution storage (default:
100)
lim:memory (memory)
#maximal memory usage in MB; reported memory usage is lower than real
memory usage! (default: 8796093022207.0)
lim:nodes
Maximal number of nodes to process (default: -1: no limit)
lim:restarts
Solving stops, if the given number of restarts was triggered (default:
-1: no limit)
lim:softtime (softtime)
Soft time limit which should be applied after first solution was found
(default: -1.0: disabled)
lim:solutions
Solving stops, if the given number of solutions were found (default: -1:
no limit)
lim:stallnodes
Solving stops, if the given number of nodes was processed since the last
improvement of the primal solution value (default: -1: no limit)
lim:time (timelim, timelimit, time_limit)
Limit on solve time (in seconds; default: 1e+20).
lim:totalnodes
Maximal number of total nodes (incl. restarts) to process (default: -1:
no limit)
lp:alwaysgetduals (alwaysgetfarkasduals, alwaysgetduals)
0/1: whether the Farkas duals should always be collected when an LP is
found to be infeasible
0 - The Farkas duals should not always be collected when an LP is found
to be infeasible (default)
1 - The Farkas duals should always be collected when an LP is found to
be infeasible.
lp:presolving
0/1: whether presolving of LP solver should be used
0 - Presolving of LP solver should not be used
1 - Presolving of LP solver should be used (default).
lp:pricing (pricing)
Pricing strategy:
l - lpi default (default)
a - auto
f - full pricing
p - partial
s - steepest edge pricing
q - quickstart steepest edge pricing
d - devex pricing
lp:solvedepth
Maximal depth for solving LP at the nodes (default: -1: no depth limit)
lp:solvefreq
Frequency for solving LP at the nodes (-1: never; 0: only root LP;
default: 1)
lp:threads
Number of threads used for solving the LP (default: 0: automatic)
mip:bestbound (bestbound, return_bound)
Whether to return suffix .bestbound for the best known MIP dual bound on
the objective value:
0 - No (default)
1 - Yes.
The suffix is on the objective and problem and is -Infinity for
minimization problems and +Infinity for maximization problems if there
are no integer variables or if a dual bound is not available.
mip:return_gap (return_mipgap)
Whether to return mipgap suffixes or include mipgap values (|objectve -
.bestbound|) in the solve_message: sum of
1 - Return .relmipgap suffix (relative to |obj|)
2 - Return .absmipgap suffix (absolute mipgap)
4 - Suppress mipgap values in solve_message.
Default = 0. The suffixes are on the objective and problem. Returned
suffix values are +Infinity if no integer-feasible solution has been
found, in which case no mipgap values are reported in the solve_message.
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.
misc:allowstrongdualreds (allowstrongdualreds)
0/1: whether strong dual reductions should be allowed in propagation and
presolving
0 - Strong dual reductions should not be allowed in propagation and
presolving
1 - Strong dual reductions should be allowed in propagation and
presolving (default).
misc:allowweakdualreds (allowweakdualreds)
0/1: whether weak dual reductions should be allowed in propagation and
presolving
0 - Weak dual reductions should not be allowed in propagation and
presolving
1 - Weak dual reductions should be allowed in propagation and presolving
(default).
misc:scaleobj (scaleobj)
0/1: whether the objective function should be scaled so that it is
always integer
0 - The objective function should not be scaled so that it is always
integer
1 - The objective function should be scaled so that it is always integer
(default).
nlp:disable
0/1: whether the NLP relaxation should be always disabled (also for
NLPs/MINLPs)
0 - NLP relaxation should not be always disabled (default)
1 - NLP relaxation should be always disabled.
nod:childsel
Child selection rule:
d - down
u - up
p - pseudo costs
i - inference
l - lp value
r - root LP value difference
h - hybrid inference/root LP value difference (default)
num:checkfeastolfac (checkfeastolfac)
Feasibility tolerance factor; for checking the feasibility of the best
solution (default: 1.0)
num:dualfeastol (dualfeastol)
Feasibility tolerance for reduced costs in LP solution (default: 1e-07)
num:epsilon (epsilon)
Absolute values smaller than this are considered zero (default: 1e-09)
num:feastol (feastol)
Feasibility tolerance for constraints (default: 1e-06)
num:infinity (infinity)
Values larger than this are considered infinity (default: 1e+20)
num:lpfeastolfactor (lpfeastolfactor)
Factor w.r.t. primal feasibility tolerance that determines default (and
maximal) primal feasibility tolerance of LP solver (default: 1.0)
num:sumepsilon (sumepsilon)
Absolute values of sums smaller than this are considered (default:
1e-06)
obj:multi (multiobj)
Whether to use multi-objective optimization:
0 - Single objective, see option obj:no (default)
1 - Multi-objective, solver's native handling if available
2 - Multi-objective, force emulation
When obj:multi>0 and several objectives are present, suffixes
.objpriority, .objweight, .objreltol, and .objabstol on the objectives
are relevant. Objectives with greater .objpriority values (integer
values) have higher priority. Objectives with the same .objpriority are
weighted by .objweight, according to the option obj:multi:weight.
Objectives with positive .objabstol or .objreltol are allowed to be
degraded by lower priority objectives by amounts not exceeding the
.objabstol (absolute) and .objreltol (relative) limits.
Note that with solver's native handling (when obj:multi=1 and
supported), some solvers might have special rules for the tolerances,
especially for LP, and not allow quadratic objectives. See the solver
documentation.
obj:multi:weight (multiobjweight, obj:multi:weights, multiobjweights)
How to interpret each objective's weight sign:
1 - relative to the sense of the 1st objective
2 - relative to its own sense (default)
With the 1st option (legacy behaviour), negative .objweight for
objective i would make objective i's sense the opposite of the model's
1st objective. Otherwise, it would make objective i's sense the opposite
to its sense defined in the model.
obj:no (objno)
Objective to optimize:
0 - None
1 - First (default, if available)
2 - Second (if available), etc.
par:maxnthreads (maxnthreads)
Maximum number of threads used during parallel solve (default: 8)
par:minnthreads (minnthreads)
Minimum number of threads used during parallel solve (default: 1)
par:mode (mode)
0/1: Parallel optimisation mode
0 - Opportunistic
1 - Deterministic (default)
pre:abortfac (abortfac)
Abort presolve, if at most this fraction of the problem was changed in
last presolve round (default: 0.0008)
pre:clqtablefac (clqtablefac)
Limit on number of entries in clique table relative to number of problem
nonzeros (default: 2.0)
pre:donotaggr (donotaggr)
0/1: whether aggregation of variables should be forbidden
0 - Aggregation of variables should not be forbidden (default)
1 - Aggregation of variables should be forbidden.
pre:donotmultaggr (donotmultaggr)
0/1: whether multi-aggregation of variables should be forbidden
0 - Multi-aggregation of variables should not be forbidden (default)
1 - Multi-aggregation of variables should be forbidden.
pre:immrestartfac (immrestartfac)
Fraction of integer variables that were fixed in the root node
triggering an immediate restart with preprocessing (default: 0.1)
pre:maxrestarts
Maximal number of restarts (default: -1: unlimited)
pre:maxrounds
Maximal number of presolving rounds (default: -1: unlimited; 0: off)
pre:restartfac (restartfac)
Fraction of integer variables that were fixed in the root node
triggering a restart with preprocessing after root node evaluation
(default: 0.025)
pre:restartminred (restartminred)
Minimal fraction of integer variables removed after restart to allow for
an additional restart (default: 0.1)
pre:settings
0/1/2/3: sets presolvings settings
0 - Sets presolvings default (default)
1 - Sets presolvings aggressive
2 - Sets presolvings fast
3 - Sets presolvings off.
pre:subrestartfac (subrestartfac)
Fraction of integer variables that were globally fixed during the
solving process triggering a restart with preprocessing (default: 1.0)
pro:abortoncutoff
0/1: whether propagation should be aborted immediately (setting this to
0 could help conflict analysis to produce more conflict constraints)
0 - Propagation should not be aborted immediately
1 - Propagation should be aborted immediately (default).
pro:maxrounds
Maximal number of propagation rounds per node (-1: unlimited; 0: off;
default: 100)
pro:maxroundsroot
Maximal number of propagation rounds in the root node (-1: unlimited; 0:
off; default: 1000)
ran:lpseed (lpseed)
Random seed for LP solver, e.g. for perturbations in the simplex
(default: 0: LP default)
ran:permutationseed (permutationseed)
Seed value for permuting the problem after reading/transformation
(default: 0: no permutation)
ran:permuteconss (permuteconss)
0/1: whether the order of constraints should be permuted (depends on
permutationseed)?
0 - Order of constraints should not be permuted
1 - Order of constraints should be permuted (default).
ran:permutevars (permutevars)
0/1: whether the order of variables should be permuted (depends on
permutationseed)?
0 - Order of variables should not be permuted (default)
1 - Order of variables should be permuted.
ran:randomseedshift (randomseedshift)
Global shift of all random seeds in the plugins and the LP random seed
(default: 0)
sol:chk:fail (chk:fail, checkfail)
Fail on MP solution check violations, with solve result 150.
sol:chk:feastol (sol:chk:eps, chk:eps, chk:feastol)
Absolute tolerance to check objective values, variable and constraint
bounds. Default 1e-6.
sol:chk:feastolrel (sol:chk:epsrel, chk:epsrel, chk:feastolrel)
Relative tolerance to check objective values, variable and constraint
bounds. Default 1e-6.
sol:chk:infeas (chk:infeas, checkinfeas)
Check even infeasible solution condidates, whenever solver reports them.
sol:chk:inttol (sol:chk:inteps, sol:inteps, chk:inttol)
Solution checking tolerance for variables' integrality. Default 1e-5.
sol:chk:mode (solcheck, checkmode, chk:mode)
Solution checking mode. Sum of a subset of the following bits:
1 - Check variable bounds and integrality.
2 - Check original model constraints, as well as any non-linear
expression values reported by the solver.
4 - Check intermediate auxiliary constraints (i.e., those which were
reformulated further).
8 - Check final auxiliary constraints sent to solver.
16 - Check objective values.
32, 64, 128, 256, 512 - similar, but non-linear expressions are
recomputed (vs using their values reported by the solver.)
*Experimental.* This is an idealistic check, because it does not
consider possible tolerances applied by the solver when computing
expression values.
Default: 1+2+512.
sol:chk:prec (chk:prec, chk:precision)
AMPL solution_precision option when checking: number of significant
digits.
sol:chk:round (chk:round, chk:rnd)
AMPL solution_round option when checking: round to this number of
decimals after comma (before comma if negative.)
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".
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:logfile (logfile)
Log file name.
tech:optionfile (optionfile, option:file)
Name of an AMPL 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",
e.g., "lim:iter=500".
tech:optionnativeread (optionnativeread, tech:param:read, param:read)
Filename of SCIP parameter file (as path).The suffix on a parameter file
should be .set.
tech:outlev (outlev)
0*/1: Whether to write SCIP log lines (chatter) to stdout and to file.
tech:outlev-native (outlev-native)
0*/1/2/3/4/5: Whether to write SCIP log lines (chatter) to stdout and to
file (native output level of SCIP).
tech:timing (timing, tech:report_times, report_times)
0*/1/2: Whether to print and return timings for the run, all times are
wall times. If set to 1, return the solution times in the problem
suffixes 'time_solver', 'time_setup' and 'time', 'time'=
time_solver+time_setup+time_output is a measure of the total time spent
in the solver driver. If set to 2, return more granular times, including
'time_read', 'time_conversion' and 'time_output'.
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 (cvt:writegraph, writegraph, exportgraph)
File to export conversion graph. Format: JSON Lines.