Options#

Options class to set GAMS options for the model.

Attributes:

cns: str | None

Default cns solver

dnlp: str | None

Default dnlp solver

emp: str | None

Default emp solver

lp: str | None

Default lp solver

mcp: str | None

Default mcp solver

minlp: str | None

Default minlp solver

mip: str | None

Default mip solver

miqcp: str | None

Default miqcp solver

mpec: str | None

Default mpec solver

nlp: str | None

Default nlp solver

qcp: str | None

Default qcp solver

rminlp: str | None

Default rminlp solver

rmip: str | None

Default rmip solver

rmiqcp: str | None

Default rmiqcp solver

rmpec: str | None

Default rmpec solver

allow_suffix_in_equation: bool | None

Flag to allow variables with suffixes in model algebra

allow_suffix_in_limited_variables: bool | None

Flag to allow domain limited variables with suffixes in model

basis_detection_threshold: float | None

Basis detection threshold

compile_error_limit: int = 1

Compile time error limit

domain_violation_limit: int | None

Domain violation limit

cutoff: float | None

Within a branch-and-bound based solver, the parts of the tree with an objective value worse than the cutoff value are ignored. Note that this may speed up the initial phase of the branch and bound algorithm (before the first integer solution is found). However, the true optimum may be beyond the cutoff value. In this case the true optimum will be missed and moreover, no solution will be found. Observe that this option is specified in absolute terms.

default_point: int | None

This option determines the point that is passed to the solver as a basis. By default, the levels and marginals from the current basis are passed to the solver. In some circumstances (mostly during debugging), it can be useful to pass a standard default input point, i.e. with all levels set to 0 or lower bound.

Option 0 Pass user defined levels and marginals to solver
Option 1 Pass default levels and marginals to solver
Option 2 Pass default marginals to solver

generate_name_dict: bool | None

If this option is set, it will instruct GAMS to make the GAMS names of variables and equations that have been generated by the solve statement available to the solver. In many solver links, these names are registered with the solver and hence messages from the solver that involve variables and equations (e.g. an infeasible row or duplicate columns) can be easily interpreted by the user. However, the dictionary comes at a price. Generating the names and calculating and storing the map takes time and space. In addition, GAMS names take up space in the solver. Thus, if the user needs very fast generation and does not need names, setting dictFile to zero is a good option.

enable_scaling: bool | None

This option determines whether GAMS will employ user-specified variable and equation scaling factors. It must be set to True if scaling factors are to be used.

enable_prior: bool | None

Instructs the solver to use the priority branching information passed by GAMS through variable suffix values variable.prior. If and how priorities are used is solver-dependent.

infeasibility_tolerance: float | None

This option sets the tolerance for marking an equation infeasible in the equation listing. By default, 1.0e-13.

try_partial_integer_solution: bool | None

Signals the solver to make use of a partial or near-integer-feasible solution stored in current variable values to get a quick integer-feasible point. The exact form of implementation depends on the solver and may be partly controlled by solver settings or options. See the solver manuals for details.

try_linear_solution: bool | None

Examine empirical NLP model to see if there are any NLP terms active. If there are none the default LP solver will be used. If this option is set to True, empirical NLP models will be examined to determine if there are any active NLP terms. If there are none, the default LP solver will be used. The procedure also checks to see if QCP and DNLP models can be reduced to an LP; MIQCP and MINLP can be solved as a MIP; RMIQCP and RMINLP can be solved as an RMIP.

job_time_limit: float | None

Elapsed time limit (seconds)

job_heap_limit: float | None

Maximum Heap size allowed (MB)

hold_fixed_variables: bool | None

Treat fixed variables as constants

integer_variable_upper_bound: int | None

Set mode for default upper bounds on integer variables

iteration_limit: int | None

Iteration limit of solver

keep_temporary_files: bool = False

Controls keeping or deletion of process directory and scratch files

listing_file: str | None

Listing file name

loadpoint: str | None

Path to the loadpoint GDX file that contains starting point records.

log_file: str | None

Log file name

variable_listing_limit: int

Maximum number of columns listed in one variable block

equation_listing_limit: int

Maximum number of rows listed in one equation block

min_improvement_threshold: float | None

For a branch-and-bound based solver, each new feasible solution must be at least the value of min_improvement_threshold better than the current best feasible solution. Note that this may speed up the search, but may cause some solutions, including optimal ones, to be missed. If a model has been solved with a nonzero min_improvement_threshold, then the optimal solution will be within the min_improvement_threshold or less of the found solution. Observe that the option min_improvement_threshold is specified in absolute terms, therefore non-negative values are appropriate for both minimization and maximization models.

node_limit: int | None

Node limit in branch and bound tree

absolute_optimality_gap: float | None

Absolute Optimality criterion solver default

relative_optimality_gap: float | None

Relative Optimality criterion solver default

memory_tick_interval: float | None

Wait interval between memory monitor checks: ticks = milliseconds

monitor_process_tree_memory: bool | None

Monitor the memory used by the GAMS process tree

profile: int | None

Execution profiling

profile_file: str

Write profile information to this file

profile_tolerance: float | None

Minimum time a statement must use to appear in profile generated output

reference_file: str | None

Symbol reference file

time_limit: float | None

Wall-clock time limit for solver

savepoint: Optional[Literal[0, 1, 2, 3, 4]] = None

Save solver point in GDX file

Option 0: No point GDX file is to be saved
Option 1: A point GDX file from the last solve is to be saved
Option 2: A point GDX file from every solve is to be saved
Option 3: A point GDX file from the last solve is to be saved in the scratch directory
Option 4: A point GDX file from every solve is to be saved in the scratch directory

seed: int | None

Random number seed

report_solution: Literal[0, 1, 2] = 2

Solution report print option

Option 0: Remove solution listings following solves
Option 1: Include solution listings following solves
Option 2: Suppress all solution information

show_os_memory: Literal[0, 1, 2] = 0

Show the memory usage reported by the Operating System instead of the internal counting

Option 0: Show memory reported by internal accounting
Option 1: Show resident set size reported by operating system
Option 2: Show virtual set size reported by operating system

solver_link_type: Optional[Literal[0, 1, 2, 3, 4, 5, 6, 7]] = None

Solver link option

Option 0: Model instance and entire GAMS state saved to scratch directory, GAMS exits (and vacates memory), and the solver script is called. After the solver terminates, GAMS restarts from the saved state and continues to executing
Option 1: Model instance saved to scratch directory, the solver is called from a shell while GAMS remains open
Option 2: Model instance saved to scratch directory, the solver is called with a spawn (if possible) or a shell (if spawn is not possible) while GAMS remains open - If this is not supported by the selected solver, it gets reset to 1 automatically
Option 3: Model instance saved to scratch directory, the solver starts the solution and GAMS continues
Option 4: Model instance saved to scratch directory, the solver starts the solution and GAMS waits for the solver to come back but uses same submission process as 3 (test mode)
Option 5: The model instance is passed to the solver in-memory - If this is not supported by the selected solver, it gets reset to 2 automatically
Option 6: The model instance is passed to the solver in-memory, the solver starts the solution and GAMS continues
Option 7: The model instance is passed to the solver in-memory, the solver starts the solution and GAMS waits for the solver to come back but uses same submission process as 6 (test mode)

merge_strategy: Optional[Literal[“replace”, “merge”, “clear”]] = None

Replace: The solution information for all equations and variables is merged into the existing solution information
Merge: The solution information for all equations appearing in the model is completely replaced by the new model results; variables are only replaced if they appear in the final model
Clear: The solution information for all equations appearing in the model is completely replaced; in addition, variables appearing in the symbolic equations but removed by conditionals will be removed

step_summary: bool | None

Summary of computing resources used by job steps

suppress_compiler_listing: bool = False

Compiler listing option

report_solver_status: bool | None

Solver Status file reporting option

threads: int | None

Number of processors to be used by a solver

write_listing_file: bool = True

Switch to write a Listing file

zero_rounding_threshold: float | None

The results of certain operations will be set to zero if abs(result) LE ZeroRes

report_underflow: bool | None

Report underflow as a warning when abs(results) LE ZeroRes and result set to zero

Methods

`export`(pf_file[, output])	Exports options to the pf_file.
`fromFile`(path)	Generates an Options object with the key-value pairs in a file.

enable_scaling: bool | None#

enable_prior: bool | None#

infeasibility_tolerance: float | None#

try_partial_integer_solution: bool | None#

try_linear_solution: bool | None#

min_improvement_threshold: float | None#

static fromFile(path: str) → Options[source]#

Generates an Options object with the key-value pairs in a file. The file in given path must consist of one key-value pair in each line.

Parameters:

pathstr: Path to the option file.

Returns:

Options

Raises:

ValidationError: In case the given path is not a file.

export(pf_file: str, output: TextIOWrapper | None = None) → None[source]#

Exports options to the pf_file. Each line contains a key-value pair.

Parameters:

pf_filestr
outputio.TextIOWrapper | None, optional