[List of options](@id option-definitions)

[presolve](@id option-presolve)

• Presolve: "off", "choose" or "on"
• Type: string
• Default: "choose"

[solver](@id option-solver)

• LP/QP solver: "choose", "simplex", "ipm", "ipx", "hipo", "pdlp", "qpasm" or "hipdlp",
• Type: string
• Default: "choose"

[parallel](@id option-parallel)

• Parallel: "off", "choose" or "on"
• Type: string
• Default: "choose"

[threads](@id option-threads)

• Maximum number of threads used by HiGHS (0: automatic)
• Type: integer
• Range: {0, 2147483647}
• Default: 0

[run_crossover](@id option-run-crossover)

• Run IPM crossover: "off", "choose" or "on"
• Type: string
• Default: "on"

[time_limit](@id option-time-limit)

• Time limit (seconds)
• Type: double
• Range: [0, inf]
• Default: inf

[ranging](@id option-ranging)

• Compute cost, bound, RHS and basic solution ranging: "off" or "on"
• Type: string
• Default: "off"

[infinite_cost](@id option-infinite-cost)

• Limit on |cost coefficient|: values greater than or equal to this will be treated as infinite
• Type: double
• Range: [1e+15, inf]
• Default: 1e+20

[infinite_bound](@id option-infinite-bound)

• Limit on |constraint bound|: values greater than or equal to this will be treated as infinite
• Type: double
• Range: [1e+15, inf]
• Default: 1e+20

[small_matrix_value](@id option-small-matrix-value)

• Lower limit on |matrix entries|: values less than or equal to this will be treated as zero
• Type: double
• Range: [1e-12, inf]
• Default: 1e-09

[large_matrix_value](@id option-large-matrix-value)

• Upper limit on |matrix entries|: values greater than or equal to this will be treated as infinite
• Type: double
• Range: [1, inf]
• Default: 1e+15

[kkt_tolerance](@id option-kkt-tolerance)

• If changed from its default value, this tolerance is used for all feasibility and optimality (KKT) measures
• Type: double
• Range: [1e-10, inf]
• Default: 1e-07

[primal_feasibility_tolerance](@id option-primal-feasibility-tolerance)

• Primal feasibility tolerance
• Type: double
• Range: [1e-10, inf]
• Default: 1e-07

[dual_feasibility_tolerance](@id option-dual-feasibility-tolerance)

• Dual feasibility tolerance
• Type: double
• Range: [1e-10, inf]
• Default: 1e-07

[primal_residual_tolerance](@id option-primal-residual-tolerance)

• Primal residual tolerance
• Type: double
• Range: [1e-10, inf]
• Default: 1e-07

[dual_residual_tolerance](@id option-dual-residual-tolerance)

• Dual residual tolerance
• Type: double
• Range: [1e-10, inf]
• Default: 1e-07

[optimality_tolerance](@id option-optimality-tolerance)

• Optimality tolerance
• Type: double
• Range: [1e-10, inf]
• Default: 1e-07

[objective_bound](@id option-objective-bound)

• Objective bound for termination of the dual simplex solver
• Type: double
• Range: [-inf, inf]
• Default: inf

[objective_target](@id option-objective-target)

• Objective target for termination of the MIP solver
• Type: double
• Range: [-inf, inf]
• Default: -inf

[random_seed](@id option-random-seed)

• Random seed used in HiGHS
• Type: integer
• Range: {0, 2147483647}
• Default: 0

[user_objective_scale](@id option-user-objective-scale)

• Exponent of power-of-two objective scaling for model
• Type: integer
• Range: {-2147483647, 2147483647}
• Default: 0

[user_bound_scale](@id option-user-bound-scale)

• Exponent of power-of-two bound scaling for model
• Type: integer
• Range: {-2147483647, 2147483647}
• Default: 0

[simplex_strategy](@id option-simplex-strategy)

• Strategy for simplex solver 0 => Choose; 1 => Dual (serial); 2 => Dual (SIP); 3 => Dual (PAMI); 4 => Primal
• Type: integer
• Range: {0, 4}
• Default: 1

[simplex_scale_strategy](@id option-simplex-scale-strategy)

• Simplex scaling strategy: off / choose / equilibration (default) / forced equilibration / max value (0/1/2/3/4)
• Type: integer
• Range: {0, 4}
• Default: 2

[simplex_dual_edge_weight_strategy](@id option-simplex-dual-edge-weight-strategy)

• Strategy for simplex dual edge weights: Choose / Dantzig / Devex / Steepest Edge (-1/0/1/2)
• Type: integer
• Range: {-1, 2}
• Default: -1

[simplex_primal_edge_weight_strategy](@id option-simplex-primal-edge-weight-strategy)

• Strategy for simplex primal edge weights: Choose / Dantzig / Devex / Steepest Edge (-1/0/1/2)
• Type: integer
• Range: {-1, 2}
• Default: -1

[simplex_iteration_limit](@id option-simplex-iteration-limit)

• Iteration limit for simplex solver when solving LPs, but not subproblems in the MIP solver
• Type: integer
• Range: {0, 2147483647}
• Default: 2147483647

[simplex_update_limit](@id option-simplex-update-limit)

• Limit on the number of simplex UPDATE operations
• Type: integer
• Range: {0, 2147483647}
• Default: 5000

[simplex_max_concurrency](@id option-simplex-max-concurrency)

• Maximum level of concurrency in parallel simplex
• Type: integer
• Range: {1, 8}
• Default: 8

[output_flag](@id option-output-flag)

• Enables or disables solver output
• Type: boolean
• Default: "true"

[log_to_console](@id option-log-to-console)

• Enables or disables console logging
• Type: boolean
• Default: "true"

[log_file](@id option-log-file)

• Log file
• Type: string
• Default: ""

[write_model_to_file](@id option-write-model-to-file)

• Write the model to a file
• Type: boolean
• Default: "false"

[write_presolved_model_to_file](@id option-write-presolved-model-to-file)

• Write the presolved model to a file
• Type: boolean
• Default: "false"

[write_solution_to_file](@id option-write-solution-to-file)

• Write the primal and dual solution to a file
• Type: boolean
• Default: "false"

[write_solution_style](@id option-write-solution-style)

• Style of solution file (raw = computer-readable, pretty = human-readable): -1 => HiGHS old raw (deprecated); 0 => HiGHS raw; 1 => HiGHS pretty; 2 => Glpsol raw; 3 => Glpsol pretty; 4 => HiGHS sparse raw
• Type: integer
• Range: {-1, 4}
• Default: 0

[glpsol_cost_row_location](@id option-glpsol-cost-row-location)

• Location of cost row for Glpsol file: -2 => Last; -1 => None; 0 => None if empty, otherwise data file location; 1 <= n <= num_row => Location n; n > num_row => Last
• Type: integer
• Range: {-2, 2147483647}
• Default: 0

[read_solution_file](@id option-read-solution-file)

• Read solution file
• Type: string
• Default: ""

[read_basis_file](@id option-read-basis-file)

• Read basis file
• Type: string
• Default: ""

[write_model_file](@id option-write-model-file)

• Write model file
• Type: string
• Default: ""

[solution_file](@id option-solution-file)

• Write solution file
• Type: string
• Default: ""

[write_basis_file](@id option-write-basis-file)

• Write basis file
• Type: string
• Default: ""

[write_presolved_model_file](@id option-write-presolved-model-file)

• Write presolved model file
• Type: string
• Default: ""

[write_iis_model_file](@id option-write-iis-model-file)

• Write IIS model file
• Type: string
• Default: ""

[mip_detect_symmetry](@id option-mip-detect-symmetry)

• Whether MIP symmetry should be detected
• Type: boolean
• Default: "true"

[mip_allow_restart](@id option-mip-allow-restart)

• Whether MIP restart is permitted
• Type: boolean
• Default: "true"

[mip_max_nodes](@id option-mip-max-nodes)

• MIP solver max number of nodes
• Type: integer
• Range: {0, 2147483647}
• Default: 2147483647

[mip_max_stall_nodes](@id option-mip-max-stall-nodes)

• MIP solver max number of nodes where estimate is above cutoff bound
• Type: integer
• Range: {0, 2147483647}
• Default: 2147483647

[mip_max_start_nodes](@id option-mip-max-start-nodes)

• MIP solver max number of nodes when completing a partial MIP start
• Type: integer
• Range: {0, 2147483647}
• Default: 500

[mip_improving_solution_save](@id option-mip-improving-solution-save)

• Whether improving MIP solutions should be saved
• Type: boolean
• Default: "false"

[mip_improving_solution_report_sparse](@id option-mip-improving-solution-report-sparse)

• Whether improving MIP solutions should be reported in sparse format
• Type: boolean
• Default: "false"

[mip_improving_solution_file](@id option-mip-improving-solution-file)

• File for reporting improving MIP solutions: not reported for an empty string ""
• Type: string
• Default: ""

[mip_root_presolve_only](@id option-mip-root-presolve-only)

• Whether MIP presolve is only applied at the root node
• Type: boolean
• Default: "false"

[mip_lifting_for_probing](@id option-mip-lifting-for-probing)

• Level of lifting for probing that is used
• Type: integer
• Range: {-1, 2147483647}
• Default: -1

[mip_max_leaves](@id option-mip-max-leaves)

• MIP solver max number of leaf nodes
• Type: integer
• Range: {0, 2147483647}
• Default: 2147483647

[mip_max_improving_sols](@id option-mip-max-improving-sols)

• Limit on the number of improving solutions found to stop the MIP solver prematurely
• Type: integer
• Range: {1, 2147483647}
• Default: 2147483647

[mip_lp_age_limit](@id option-mip-lp-age-limit)

• Maximal age of dynamic LP rows before they are removed from the LP relaxation in the MIP solver
• Type: integer
• Range: {0, 32767}
• Default: 10

[mip_pool_age_limit](@id option-mip-pool-age-limit)

• Maximal age of rows in the MIP solver cutpool before they are deleted
• Type: integer
• Range: {0, 1000}
• Default: 30

[mip_pool_soft_limit](@id option-mip-pool-soft-limit)

• Soft limit on the number of rows in the MIP solver cutpool for dynamic age adjustment
• Type: integer
• Range: {1, 2147483647}
• Default: 10000

[mip_pscost_minreliable](@id option-mip-pscost-minreliable)

• Minimal number of observations before MIP solver pseudo costs are considered reliable
• Type: integer
• Range: {0, 2147483647}
• Default: 8

[mip_min_cliquetable_entries_for_parallelism](@id option-mip-min-cliquetable-entries-for-parallelism)

• Minimal number of entries in the MIP solver cliquetable before neighbourhood queries of the conflict graph use parallel processing
• Type: integer
• Range: {0, 2147483647}
• Default: 100000

[mip_feasibility_tolerance](@id option-mip-feasibility-tolerance)

• MIP integrality tolerance
• Type: double
• Range: [1e-10, inf]
• Default: 1e-06

[mip_heuristic_effort](@id option-mip-heuristic-effort)

• Effort spent for MIP heuristics
• Type: double
• Range: [0, 1]
• Default: 0.05

[mip_heuristic_run_feasibility_jump](@id option-mip-heuristic-run-feasibility-jump)

• Use the feasibility jump heuristic
• Type: boolean
• Default: "true"

[mip_heuristic_run_rins](@id option-mip-heuristic-run-rins)

• Use the RINS heuristic
• Type: boolean
• Default: "true"

[mip_heuristic_run_rens](@id option-mip-heuristic-run-rens)

• Use the RENS heuristic
• Type: boolean
• Default: "true"

[mip_heuristic_run_root_reduced_cost](@id option-mip-heuristic-run-root-reduced-cost)

• Use the rootReducedCost heuristic
• Type: boolean
• Default: "true"

[mip_heuristic_run_zi_round](@id option-mip-heuristic-run-zi-round)

• Use the ZI Round heuristic
• Type: boolean
• Default: "false"

[mip_heuristic_run_shifting](@id option-mip-heuristic-run-shifting)

• Use the Shifting heuristic
• Type: boolean
• Default: "false"

[mip_allow_cut_separation_at_nodes](@id option-mip-allow-cut-separation-at-nodes)

• Whether cut separation at nodes other than the root node is permitted
• Type: boolean
• Default: "true"

[mip_rel_gap](@id option-mip-rel-gap)

• Tolerance on relative gap, |ub-lb|/|ub|, to determine whether optimality has been reached for a MIP instance
• Type: double
• Range: [0, inf]
• Default: 0.0001

[mip_abs_gap](@id option-mip-abs-gap)

• Tolerance on absolute gap of MIP, |ub-lb|, to determine whether optimality has been reached for a MIP instance
• Type: double
• Range: [0, inf]
• Default: 1e-06

[mip_min_logging_interval](@id option-mip-min-logging-interval)

• MIP minimum logging interval
• Type: double
• Range: [0, inf]
• Default: 5

[mip_lp_solver](@id option-mip-lp-solver)

• MIP LP solver: "choose", "simplex", "ipm", "ipx" or "hipo"
• Type: string
• Default: "choose"

[mip_ipm_solver](@id option-mip-ipm-solver)

• MIP IPM solver: "choose", "ipx" or "hipo"
• Type: string
• Default: "choose"

[ipm_optimality_tolerance](@id option-ipm-optimality-tolerance)

• IPM optimality tolerance
• Type: double
• Range: [1e-12, inf]
• Default: 1e-08

[mip_search_simulate_concurrency](@id option-mip-search-simulate-concurrency)

• Simulate MIP search concurrency on a single thread
• Type: boolean
• Default: "false"

[ipm_iteration_limit](@id option-ipm-iteration-limit)

• Iteration limit for IPM solver
• Type: integer
• Range: {0, 2147483647}
• Default: 2147483647

[hipo_system](@id option-hipo-system)

• HiPO Newton system: "choose", "augmented" or "normaleq"
• Type: string
• Default: "choose"

[hipo_parallel_type](@id option-hipo-parallel-type)

• HiPO parallelism: "tree", "node" or "both"
• Type: string
• Default: "both"

[hipo_ordering](@id option-hipo-ordering)

• HiPO matrix reordering: "choose", "metis", "amd" or "rcm"
• Type: string
• Default: "choose"

[hipo_block_size](@id option-hipo-block-size)

• Block size for dense linear algebra within HiPO
• Type: integer
• Range: {0, 2147483647}
• Default: 128

[pdlp_iteration_limit](@id option-pdlp-iteration-limit)

• Iteration limit for PDLP solver
• Type: integer
• Range: {0, 2147483647}
• Default: 2147483647

[pdlp_scaling_mode](@id option-pdlp-scaling-mode)

• Scaling mode for PDLP solver (default = 5): 1 => Ruiz; 2 => L2; 4 => PC
• Type: integer
• Range: {0, 7}
• Default: 5

[pdlp_ruiz_iterations](@id option-pdlp-ruiz-iterations)

• Number of Ruiz scaling iteraitons for PDLP solver
• Type: integer
• Range: {0, 2147483647}
• Default: 10

[pdlp_restart_strategy](@id option-pdlp-restart-strategy)

• Restart strategy for PDLP solver: 0 => off; 1 => fixed; 2 => adaptive; 3 => Halpern
• Type: integer
• Range: {0, 3}
• Default: 2

[pdlp_cupdlpc_restart_method](@id option-pdlp-cupdlpc-restart-method)

• Restart mode for cuPDLP-C solver: 0 => none; 1 => GPU (default); 2 => CPU
• Type: integer
• Range: {0, 2}
• Default: 1

[pdlp_step_size_strategy](@id option-pdlp-step-size-strategy)

• Step size strategy for PDLP solver: 0 => fixed; 1 => adaptive; 2 => Malitsky-Pock; 3 => PID
• Type: integer
• Range: {0, 3}
• Default: 1

[pdlp_optimality_tolerance](@id option-pdlp-optimality-tolerance)

• PDLP optimality tolerance
• Type: double
• Range: [1e-10, inf]
• Default: 1e-07

[qp_allow_hot_start](@id option-qp-allow-hot-start)

• Allow the active set QP solver to hot start
• Type: boolean
• Default: "false"

[qp_iteration_limit](@id option-qp-iteration-limit)

• Iteration limit for the active set QP solver
• Type: integer
• Range: {0, 2147483647}
• Default: 2147483647

[qp_nullspace_limit](@id option-qp-nullspace-limit)

• Nullspace limit for the active set QP solver
• Type: integer
• Range: {0, 2147483647}
• Default: 4000

[qp_regularization_value](@id option-qp-regularization-value)

• Regularization value added to the Hessian in the active set QP solver
• Type: double
• Range: [0, inf]
• Default: 1e-07

[iis_strategy](@id option-iis-strategy)

• Strategy for IIS calculation: 0 => Light test; 1 => Try dual ray; 2 => Try elastic LP; 4 => Prioritise columns; 8 => Find true IIS; 16 => Find relaxation IIS for MIP
• Type: integer
• Range: {0, 31}
• Default: 0

[iis_time_limit](@id option-iis-time-limit)

• Time limit for computing IIS (seconds)
• Type: double
• Range: [0, inf]
• Default: inf

[blend_multi_objectives](@id option-blend-multi-objectives)

• Blend multiple objectives or apply lexicographically
• Type: boolean
• Default: "true"