SolverBase

(class from pyomo.contrib.solver.base)

class pyomo.contrib.solver.base.SolverBase(**kwds)[source]

Bases: ABC

This base class defines the methods required for all solvers:

available: Determines whether the solver is able to be run,
combining both whether it can be found on the system and if the license is valid.
solve: The main method of every solver
version: The version of the solver
is_persistent: Set to false for all non-persistent solvers.

Additionally, solvers should have a config attribute that inherits from one of SolverConfig, BranchAndBoundConfig, PersistentSolverConfig, or PersistentBranchAndBoundConfig.

__init__(**kwds) → None[source]

Methods

`__init__`(**kwds)
`available`()	Test if the solver is available on this system.
`is_persistent`()
`solve`(model, **kwargs)	Solve a Pyomo model.
`version`()

Attributes

CONFIG

Member Documentation

enum Availability(value)[source]

Bases: IntEnum

Class to capture different statuses in which a solver can exist in order to record its availability for use.

as_integer_ratio()

Return integer ratio.

Return a pair of integers, whose ratio is exactly equal to the original int and with a positive denominator.

>>> (10).as_integer_ratio()
(10, 1)
>>> (-10).as_integer_ratio()
(-10, 1)
>>> (0).as_integer_ratio()
(0, 1)

bit_count()

Number of ones in the binary representation of the absolute value of self.

Also known as the population count.

>>> bin(13)
'0b1101'
>>> (13).bit_count()
3

bit_length()

Number of bits necessary to represent self in binary.

>>> bin(37)
'0b100101'
>>> (37).bit_length()
6

conjugate(): Returns self, the complex conjugate of any int.

classmethod from_bytes(bytes, byteorder='big', *, signed=False)

Return the integer represented by the given array of bytes.

bytes: Holds the array of bytes to convert. The argument must either support the buffer protocol or be an iterable object producing bytes. Bytes and bytearray are examples of built-in objects that support the buffer protocol.
byteorder: The byte order used to represent the integer. If byteorder is ‘big’, the most significant byte is at the beginning of the byte array. If byteorder is ‘little’, the most significant byte is at the end of the byte array. To request the native byte order of the host system, use sys.byteorder as the byte order value. Default is to use ‘big’.
signed: Indicates whether two’s complement is used to represent the integer.

to_bytes(length=1, byteorder='big', *, signed=False)

Return an array of bytes representing an integer.

length: Length of bytes object to use. An OverflowError is raised if the integer is not representable with the given number of bytes. Default is length 1.
byteorder: The byte order used to represent the integer. If byteorder is ‘big’, the most significant byte is at the beginning of the byte array. If byteorder is ‘little’, the most significant byte is at the end of the byte array. To request the native byte order of the host system, use sys.byteorder as the byte order value. Default is to use ‘big’.
signed: Determines whether two’s complement is used to represent the integer. If signed is False and a negative integer is given, an OverflowError is raised.

denominator: the denominator of a rational number in lowest terms

imag: the imaginary part of a complex number

numerator: the numerator of a rational number in lowest terms

real: the real part of a complex number

abstract available() → bool[source]

Test if the solver is available on this system.

Nominally, this will return True if the solver interface is valid and can be used to solve problems and False if it cannot.

Note that for licensed solvers there are a number of “levels” of available: depending on the license, the solver may be available with limitations on problem size or runtime (e.g., ‘demo’ vs. ‘community’ vs. ‘full’). In these cases, the solver may return a subclass of enum.IntEnum, with members that resolve to True if the solver is available (possibly with limitations). The Enum may also have multiple members that all resolve to False indicating the reason why the interface is not available (not found, bad license, unsupported version, etc).

Returns:: available – An enum that indicates “how available” the solver is. Note that the enum can be cast to bool, which will be True if the solver is runable at all and False otherwise.
Return type:: SolverBase.Availability

is_persistent() → bool[source]

Returns:: is_persistent – True if the solver is a persistent solver.
Return type:: bool

abstract solve(model: BlockData, **kwargs) → Results[source]

Solve a Pyomo model.

Parameters:

model (BlockData) – The Pyomo model to be solved
**kwargs – Additional keyword arguments (including solver_options - passthrough options; delivered directly to the solver (with no validation))

Returns:

results – A results object

Return type:

Results

Keyword Arguments:

tee (TextIO_or_Logger, default=False) – tee accepts bool, io.TextIOBase, or logging.Logger (or a list of these types). True is mapped to sys.stdout. The solver log will be printed to each of these streams / destinations.
working_dir (Path, optional) – The directory in which generated files should be saved. This replaces the keepfiles option.
load_solutions (Bool, default=True) – If True, the values of the primal variables will be loaded into the model.
raise_exception_on_nonoptimal_result (Bool, default=True) – If False, the solve method will continue processing even if the returned result is nonoptimal.
symbolic_solver_labels (Bool, default=False) – If True, the names given to the solver will reflect the names of the Pyomo components. Cannot be changed after set_instance is called.
timer (optional) – A timer object for recording relevant process timing data.
threads (NonNegativeInt, optional) – Number of threads to be used by a solver.
time_limit (NonNegativeFloat, optional) – Time limit applied to the solver (in seconds).
solver_options (dict, optional) – Options to pass to the solver.

abstract version() → Tuple[source]

Returns:: version – A tuple representing the version
Return type:: tuple