KNITRO Options#
ampl: option solver knitro; # change the solver
ampl: option knitro_options 'option1=value1 option2=value2'; # specify options
ampl: solve; # solve the problem
Solver options obtained with $ knitro -=.
act_lpalg LP algorithm used in Active or SQP subproblems:
0 (default) = automatic choice
1 = primal
2 = dual
3 = barrier
act_lpdumpmps Dump LPs to MPS files in Active or SQP algorithm
act_lpfeastol Feasibility tolerance for LP subproblems
act_lppenalty Controls constraint penalization in LP subproblems
act_lppresolve Controls LP presolve in Active or SQP subproblems
act_parametric Use parametric LP in Active or SQP algorithm
act_qpalg QP subproblem alg used by Active or SQP algorithm
act_qppenalty Controls constraint penalization in QP subproblems
alg Algorithm (0=auto, 1=direct, 2=cg, 3=active,
4=sqp, 5=multi)
algorithm Synonym for alg
bar_conic_enable Special handling of conic constraints
bar_directinterval Frequency for trying to force direct steps
bar_feasible Emphasize feasibility
bar_feasmodetol Tolerance for entering stay feasible mode
bar_globalize Barrier globalization strategy
bar_initmu Initial value for barrier parameter (non-positive=auto)
bar_initpi_mpec Initial value for barrier MPEC penalty parameter
bar_initpt Barrier initial point strategy
bar_initshifttol Tolerance for shifting initial point
bar_linsys Barrier linear system form
bar_linsys_storage Barrier linear system storage
bar_maxcorrectors Maximum number of corrector steps
bar_maxcrossit Maximum number of crossover iterations
bar_maxmu Maximum value for barrier parameter
bar_maxrefactor Maximum number of KKT refactorizations allowed
bar_mpec_heuristic Whether to enable barrier MPEC heuristic
bar_murule Rule for updating the barrier parameter
bar_penaltycons Apply penalty method to constraints
bar_penaltyrule Rule for updating the penalty parameter
bar_refinement Whether to refine barrier solution
bar_relaxcons Whether to relax constraints
bar_slackboundpush Amount by which slacks are pushed inside bounds
bar_switchobj Objective for barrier switching alg
bar_switchrule Rule for barrier switching alg
bar_watchdog Enable watchdog heuristic for barrier algs?
bfgs_scaling Initial scaling for BFGS/L-BFGS Hessian
blas_numthreads Number of parallel threads for BLAS
blasoption Which BLAS/LAPACK library to use
blasoptionlib Name of dynamic BLAS/LAPACK library
bndrange Constraint/variable bound range
cg_maxit Maximum number of conjugate gradient iterations
cg_pmem Memory for incomplete Choleski
cg_precond Preconditioning method
cg_stoptol Stopping tolerance for CG subproblems
conic_numthreads Number of parallel threads for conic operations
convex Declare the problem as convex
cplexlibname Name of dynamic CPLEX library
cpuplatform Target CPU platform/architecture
debug Debugging level (0=none, 1=problem, 2=execution)
debugoptionsname Name for debug option file
delta Initial trust region radius
derivcheck Whether to use derivative checker
derivcheck_terminate Derivative checker type (1=error, 2=always)
derivcheck_tol Relative tolerance for derivative checker
derivcheck_type Derivative checker type (1=forward, 2=central)
feasible Enable feasible version
feasmodetol Tolerance for entering feasible mode
feastol Feasibility stopping tolerance
feastol_abs Absolute feasibility tolerance
feastolabs Absolute feasibility tolerance
findiff_estnoise Noise estimate for finite-difference gradients
findiff_numthreads Number of threads for finite-difference gradients
findiff_relstepsize Relative stepsize for finite-difference gradients
findiff_terminate Termination for finite-difference gradients
fstopval Stop based on obj. function value
ftol Stop based on small change in obj. function
ftol_iters Stop based on small change in obj. function
gradopt Gradient computation method
hessopt Hessian computation method
honorbnds Enforce satisfaction of the bounds
infeastol Infeasibility stopping tolerance
infeastol_iters Stop based on small change in feas. error
initpenalty Initial merit function penalty value
leastsquares Solve as a least-squares model
linesearch Which linesearch method to use
linesearch_maxtrials Maximum number of linesearch trial points
linsolver Which linear solver to use
linsolver_inexact Use inexact solver (experimental option)
linsolver_inexacttol Inexact solver tolerance (experimental option)
linsolver_maxitref Max iterative refinement steps
linsolver_nodeamalg Controls node amalgamation for linear solvers
linsolver_numthreads Number of parallel threads for linear solver
linsolver_ooc Use out-of-core option?
linsolver_ordering Ordering method for linear solvers
linsolver_pivottol Initial pivot tolerance for linear solvers
linsolver_scaling Scaling method for linear solvers
lmsize Number of limited-memory pairs stored for LBFGS
lpsolver Solver used with 'act_lpalg'. Should be 'internal',
'cplex', or 'xpress'. Default = 'internal'; cplex or
xpress must be suitably licensed. For lpsolver=...
to be useful, alg=2, 3, or 4 may also be needed.
Implicitly sets omitted keywords act_lpsolve and,
if appropriate, cplex_libname ot xpress_libname.
ma_maxtime_cpu Maximum CPU time when 'alg=multi', in seconds
ma_maxtime_real Maximum real time when 'alg=multi', in seconds
ma_outsub Enable subproblem output when 'alg=multi'
ma_terminate Termination condition when option 'alg=multi'
maxcgit deprecated, use 'cg_maxit'
maxcrossit deprecated, use 'bar_maxcrossit'
maxfevals Maximum number of function evaluations
maxit Maximum number of iterations
maxtime_cpu Maximum CPU time in seconds, per start point
maxtime_real Maximum real time in seconds, per start point
mip_branchrule MIP branching rule
mip_clique Add clique cuts
mip_cut_flowcover Add flow cover cuts
mip_cut_probing Add probing cuts
mip_cut_strategy Global MIP cut strategy
mip_cutfactor Limit on the number of cuts allowed in node subproblem (maximum number of cuts is mip_cutfactor times number of constraints in model)
mip_cutoff MIP objective cutoff value
mip_cutting_plane When to perform cutting plane procedure
mip_debug MIP debugging level (0=none, 1=all)
mip_gomory Add gomory cuts (0=none, 1=root)
mip_gub_branch Branch on GUBs (0=no, 1=yes)
mip_heuristic MIP heuristic search (deprecated, use mip_heuristic_strategy)
mip_heuristic_diving MIP diving heuristic
mip_heuristic_feaspump MIP feasibility pump heuristic
mip_heuristic_lns MIP LNS heuristic
mip_heuristic_localsearch MIP local search heuristic
mip_heuristic_maxit MIP heuristic iteration limit
mip_heuristic_misqp MIP MISQP heuristic
mip_heuristic_mpec MIP MPEC heuristic
mip_heuristic_strategy MIP heuristic strategy
mip_heuristic_terminate MIP heuristic termination
mip_implications Add logical implications (0=no, 1=yes)
mip_integer_tol Threshold for deciding integrality
mip_integral_gap_abs deprecated, use 'mip_opt_gap_abs'
mip_integral_gap_rel deprecated, use 'mip_opt_gap_rel'
mip_intvar_strategy Treatment of integer variables
mip_knapsack Add knapsack cuts
mip_liftproject Add lift and project cuts
mip_lpalg LP subproblem algorithm
mip_maxnodes Maximum nodes explored
mip_maxsepcons Maximum constraints to consider for the cut separation
mip_maxsolves Maximum subproblem solves
mip_maxtime_cpu Maximum CPU time in seconds for MIP
mip_maxtime_real Maximum real in seconds time for MIP
mip_method MIP method (0=auto, 1=BB, 2=HQG, 3=MISQP)
mip_mir Add mixed integer rounding cuts
mip_multistart Enable MIP multistart
mip_nodealg Standard node relaxation algorithm
mip_numthreads Number of threads for MIP
mip_opt_gap_abs Absolute optimality gap stop tolerance
mip_opt_gap_rel Relative optimality gap stop tolerance
mip_outinterval MIP output interval
mip_outlevel MIP output level
mip_outsub Enable MIP subproblem output
mip_pseudoinit Pseudo-cost initialization
mip_relaxable Are integer variables relaxable?
mip_restart Enable MIP restart
mip_rootalg Root node relaxation algorithm
mip_rounding MIP rounding rule
mip_selectdir MIP node selection direction
mip_selectrule MIP node selection rule
mip_skipfactor MIP number of nodes to skip for the next cut separation round
mip_strong_candlim Strong branching candidate limit
mip_strong_level Strong branching tree level limit
mip_strong_maxit Strong branching iteration limit
mip_terminate Termination condition for MIP
mip_zerohalf Add zero half cuts
ms_deterministic Use deterministic multistart
ms_enable Enable multistart
ms_initpt_cluster Clustering strategy for multistart
ms_maxbndrange Maximum unbounded variable range for multistart
ms_maxsolves Maximum Knitro solves for multistart
ms_maxtime_cpu Maximum CPU time for multistart, in seconds
ms_maxtime_real Maximum real time for multistart, in seconds
ms_num_to_save Feasible points to save from multistart
ms_numthreads Number of parallel threads for multi-start
ms_outsub Enable subproblem output for parallel multistart
ms_savetol Tol for feasible points being equal
ms_seed Seed for multistart random generator
ms_startptrange Maximum variable range for multistart
ms_terminate Termination condition for multistart
multistart Enable multistart
ncvx_qcqp_init Initialization strategy for nonconvex QCQPs
newpoint Use newpoint feature
numthreads Number of parallel threads
objno objective number: 0 = none, 1 = first (default),
2 = second (if _nobjs > 1), etc.
objrange Objective range
objrep Whether to replace
minimize obj: v;
with
minimize obj: f(x)
when variable v appears linearly
in exactly one constraint of the form
s.t. c: v >= f(x);
or
s.t. c: v == f(x);
Possible objrep values:
0 = no
1 = yes for v >= f(x) (default)
2 = yes for v == f(x)
3 = yes in both cases
optionsfile Name/location of Knitro options file if provided
opttol Optimality stopping tolerance
opttol_abs Absolute optimality tolerance
opttolabs Absolute optimality tolerance
out_csvinfo Create csv info file
out_csvname Name for csv info file
out_hints Print hints for parameter settings
out_jsoninfo Create json info file
out_jsonname Name for json info file
outappend Append to output files (0=no, 1=yes)
outdir Directory for output files
outlev Control printing level
outmode Where to direct output (0=screen, 1=file, 2=both)
outname Name for output file
par_blasnumthreads Number of parallel threads for BLAS
par_conicnumthreads Number of parallel threads for conic operations
par_lsnumthreads Number of parallel threads for linear solver
par_msnumthreads Number of parallel threads for multi-start
par_numthreads Number of parallel threads
pivot deprecated, use 'linsolver_pivottol'
presolve Enable Knitro presolver
presolve_dbg Knitro presolver debugging level
presolve_initpt Knitro presolver initial point handling
presolve_level Knitro presolver level
presolve_passes Knitro presolver pass limit
presolve_tol Knitro presolver tolerance
presolveop_redundant Constraint redundancy detection level
presolveop_substitution Substitution application level
presolveop_substitution_tol Substitution application tolerance
presolveop_substitution_zero_tol Substitution tolerance for zero rounding
presolveop_tighten Knitro presolve tightening operations
presolveop_varbnd_abs_max_val Variable bound tightening tolerance for maximal magnitude.
presolveop_varbnd_rel_min_change Variable bound tightening tolerance for minimal improvement.
qpcheck whether to check for a QP: deprecated
relax whether to ignore integrality: 0 (default) = no, 1 = yes
restarts Maximum number of restarts allowed
restarts_maxit Maximum number of iterations before restarting
scale Scaling option
scale_vars Variable scaling strategy
soc Second order correction options
storequadcoefs Store quadratic coefficients when solving QCQPs
strat_warm_start Enable warm-start strategy?
threads Number of parallel threads
timing Whether to report problem I/O and solve times:
0 (default) = no
1 = yes, on stdout
2 = yes, on stderr
3 = yes, on both stdout and stderr
tuner Enables Knitro Tuner
tuner_maxtime_cpu Maximum CPU time when 'tuner=on', in seconds
tuner_maxtime_real Maximum real time when 'tuner=on', in seconds
tuner_optionsfile Name/location of Tuner options file if provided
tuner_outsub Enable subproblem output when 'tuner=on'
tuner_terminate Termination condition when 'tuner=on'
version Report software version
wantsol Solution report without -AMPL: sum of
1 ==> write .sol file
2 ==> 1 ==> write .sol file
4 ==> print dual variable values
8 ==> do not print solution message
xpresslibname Name of dynamic Xpress library
xtol Stepsize stopping tolerance
xtol_iters Stop based on small change in variables