#
# GAMS - General Algebraic Modeling System Python API
#
# Copyright (c) 2023 GAMS Development Corp. <support@gams.com>
# Copyright (c) 2023 GAMS Software GmbH <support@gams.com>
#
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# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#
from __future__ import annotations
import itertools
from enum import Enum
from typing import Any
from typing import TYPE_CHECKING
import gams.transfer as gt
import pandas as pd
from gams.core.gdx import GMS_DT_EQU
from gams.transfer._internals import EQU_TYPE
from gams.transfer._internals import TRANSFER_TO_GAMS_EQUATION_SUBTYPES
import gamspy as gp
import gamspy._algebra.condition as condition
import gamspy._algebra.expression as expression
import gamspy._algebra.operable as operable
import gamspy._symbols.implicits as implicits
import gamspy._validation as validation
from gamspy._symbols.symbol import Symbol
if TYPE_CHECKING:
from gamspy import Set, Variable, Container
from gamspy._algebra.operation import Operation
from gamspy._algebra.expression import Expression
eq_types = ["=e=", "=l=", "=g="]
non_regular_map = {
"nonbinding": "=n=",
"external": "=x=",
"cone": "=c=",
"boolean": "=b=",
}
[docs]class EquationType(Enum):
REGULAR = "REGULAR"
NONBINDING = "NONBINDING"
EXTERNAL = "EXTERNAL"
CONE = "CONE"
BOOLEAN = "BOOLEAN"
[docs] @classmethod
def values(cls):
"""Convenience function to return all values of enum"""
return list(cls._value2member_map_.keys())
def __str__(self) -> str:
return self.value
[docs]class Equation(gt.Equation, operable.Operable, Symbol):
"""
Represents an Equation symbol in GAMS.
https://www.gams.com/latest/docs/UG_Equations.html
Parameters
----------
container : Container
name : str
type : str
domain : List[Set | str], optional
definition: Expression, optional
records : Any, optional
domain_forwarding : bool, optional
description : str, optional
uels_on_axes: bool
definition_domain: list, optional
is_miro_output : bool
Examples
--------
>>> import gamspy as gp
>>> m = gp.Container()
>>> i = gp.Set(m, "i", records=['i1','i2'])
>>> a = gp.Parameter(m, "a", [i], records=[['i1',1],['i2',2]])
>>> v = gp.Variable(m, "v", domain=[i])
>>> e = gp.Equation(m, "e", domain=[i])
>>> e[i] = a[i] <= v[i]
"""
@classmethod
def _constructor_bypass(
cls,
container: Container,
name: str,
type: str | EquationType = "regular",
domain: list[Set | str] | None = None,
records: Any | None = None,
description: str = "",
):
# create new symbol object
obj = Equation.__new__(
cls,
container,
name,
type,
domain,
records=records,
description=description,
)
# set private properties directly
type = cast_type(type)
obj.type = EQU_TYPE[type]
obj._gams_type = GMS_DT_EQU
obj._gams_subtype = TRANSFER_TO_GAMS_EQUATION_SUBTYPES[type]
obj._requires_state_check = False
obj._container = container
container._requires_state_check = True
obj._name = name
obj._domain = domain
obj._domain_forwarding = False
obj._description = description
obj._records = None
obj._modified = True
# add to container
container.data.update({name: obj})
# gamspy attributes
obj._is_dirty = False
obj._is_frozen = False
obj.where = condition.Condition(obj)
obj.container._add_statement(obj)
# create attributes
obj._l, obj._m, obj._lo, obj._up, obj._s = obj._init_attributes()
obj._stage = obj._create_attr("stage")
obj._range = obj._create_attr("range")
obj._slacklo = obj._create_attr("slacklo")
obj._slackup = obj._create_attr("slackup")
obj._slack = obj._create_attr("slack")
obj._infeas = obj._create_attr("infeas")
# miro support
obj._is_miro_output = False
return obj
def __new__(
cls,
container: Container,
name: str,
type: str | EquationType = "regular",
domain: list[Set | str] | None = None,
definition: Variable | Operation | Expression | None = None,
records: Any | None = None,
domain_forwarding: bool = False,
description: str = "",
uels_on_axes: bool = False,
is_miro_output: bool = False,
definition_domain: list | None = None,
):
if not isinstance(container, gp.Container):
raise TypeError(
f"Container must of type `Container` but found {container}"
)
if not isinstance(name, str):
raise TypeError(f"Name must of type `str` but found {name}")
try:
symbol = container[name]
if isinstance(symbol, cls):
return symbol
raise TypeError(
f"Cannot overwrite symbol `{name}` in container"
" because it is not an Equation object)"
)
except KeyError:
return object.__new__(cls)
def __init__(
self,
container: Container,
name: str,
type: str | EquationType = "regular",
domain: list[Set | str] | None = None,
definition: Variable | Operation | Expression | None = None,
records: Any | None = None,
domain_forwarding: bool = False,
description: str = "",
uels_on_axes: bool = False,
is_miro_output: bool = False,
definition_domain: list | None = None,
):
# miro support
self._is_miro_output = is_miro_output
# domain handling
if domain is None:
domain = []
if isinstance(domain, (gp.Set, gp.Alias, str)):
domain = [domain]
# does symbol exist
has_symbol = False
if isinstance(getattr(self, "container", None), gp.Container):
has_symbol = True
if has_symbol:
type = cast_type(type)
if self.type != type.casefold():
raise TypeError(
"Cannot overwrite symbol in container unless equation"
f" types are equal: `{self.type}` !="
f" `{type.casefold()}`"
)
if any(
d1 != d2
for d1, d2 in itertools.zip_longest(self.domain, domain)
):
raise ValueError(
"Cannot overwrite symbol in container unless symbol"
" domains are equal"
)
if self.domain_forwarding != domain_forwarding:
raise ValueError(
"Cannot overwrite symbol in container unless"
" 'domain_forwarding' is left unchanged"
)
# reset some properties
self._requires_state_check = True
self.container._requires_state_check = True
if description != "":
self.description = description
previous_state = self.container.miro_protect
self.container.miro_protect = False
self.records = None
self.modified = True
# only set records if records are provided
if records is not None:
self.setRecords(records, uels_on_axes=uels_on_axes)
self.container.miro_protect = previous_state
else:
type = cast_type(type)
self._is_dirty = False
self._is_frozen = False
name = validation.validate_name(name)
if is_miro_output:
name = name.lower()
previous_state = container.miro_protect
container.miro_protect = False
super().__init__(
container,
name,
type,
domain,
domain_forwarding=domain_forwarding,
description=description,
uels_on_axes=uels_on_axes,
)
if is_miro_output:
container._miro_output_symbols.append(self.name)
validation.validate_container(self, self.domain)
self.where = condition.Condition(self)
self.container._add_statement(self)
self._definition_domain = definition_domain
self._init_definition(definition)
# create attributes
self._l, self._m, self._lo, self._up, self._s = (
self._init_attributes()
)
self._stage = self._create_attr("stage")
self._range = self._create_attr("range")
self._slacklo = self._create_attr("slacklo")
self._slackup = self._create_attr("slackup")
self._slack = self._create_attr("slack")
self._infeas = self._create_attr("infeas")
if records is not None:
self.setRecords(records, uels_on_axes=uels_on_axes)
else:
self.container._run()
container.miro_protect = previous_state
def __hash__(self):
return id(self)
def __getitem__(self, indices: tuple | str):
domain = validation.validate_domain(self, indices)
return implicits.ImplicitEquation(
self, name=self.name, type=self.type, domain=domain # type: ignore # noqa: E501
)
def __setitem__(
self,
indices: tuple | str | implicits.ImplicitSet,
assignment: Expression,
):
domain = validation.validate_domain(self, indices)
self._set_definition(assignment, domain)
self._is_dirty = True
if not self.container.delayed_execution:
self.container._run()
def __eq__(self, other): # type: ignore
return expression.Expression(self, "=e=", other)
def _init_attributes(self) -> tuple:
level = self._create_attr("l")
marginal = self._create_attr("m")
lower = self._create_attr("lo")
upper = self._create_attr("up")
scale = self._create_attr("scale")
return level, marginal, lower, upper, scale
def _create_attr(self, attr_name):
return implicits.ImplicitParameter(
self,
name=f"{self.name}.{attr_name}",
records=self.records,
domain=self.domain,
)
def _init_definition(
self,
assignment: Variable | Operation | Expression | None = None,
) -> None:
if assignment is None:
self._definition = None # type: ignore
return None
domain = (
self._definition_domain if self._definition_domain else self.domain
)
self._set_definition(assignment, domain)
def _set_definition(self, assignment, domain):
# In case of an MCP equation without any equality, add the equality
if not any(eq_type in assignment.gamsRepr() for eq_type in eq_types):
assignment = assignment == 0
if self.type in non_regular_map:
assignment.replace_operator(non_regular_map[self.type])
statement = expression.Expression(
implicits.ImplicitEquation(
self,
name=self.name,
type=self.type,
domain=domain,
),
"..",
assignment,
)
self.container._add_statement(statement)
self._definition = statement
@property
def l(self): # noqa: E741, E743
"""
Level
Returns
-------
ImplicitParameter
"""
return self._l
@l.setter
def l(self, value: int | float | Expression):
self._l[...] = value
@property
def m(self):
"""
Marginal
Returns
-------
ImplicitParameter
"""
return self._m
@m.setter
def m(self, value: int | float | Expression):
self._m[...] = value
@property
def lo(self):
"""
Lower bound
Returns
-------
ImplicitParameter
"""
return self._lo
@lo.setter
def lo(self, value: int | float | Expression):
self._lo[...] = value
@property
def up(self):
"""
Upper bound
Returns
-------
ImplicitParameter
"""
return self._up
@up.setter
def up(self, value: int | float | Expression):
self._up[...] = value
@property
def scale(self):
"""
Scale
Returns
-------
ImplicitParameter
"""
return self._s
@scale.setter
def scale(self, value: int | float | Expression):
self._s[...] = value
@property
def stage(self):
"""
Stage
Returns
-------
ImplicitParameter
"""
return self._stage
@stage.setter
def stage(self, value: int | float | Expression):
self._stage[...] = value
@property
def range(self):
"""
Range
Returns
-------
ImplicitParameter
"""
return self._range
@property
def slacklo(self):
"""
Slack lower bound
Returns
-------
ImplicitParameter
"""
return self._slacklo
@property
def slackup(self):
"""
Slack upper bound
Returns
-------
ImplicitParameter
"""
return self._slackup
@property
def slack(self):
"""
Slack
Returns
-------
ImplicitParameter
"""
return self._slack
@property
def infeas(self):
"""
Infeasability
Returns
-------
ImplicitParameter
"""
return self._infeas
@property
def records(self):
"""
Records of the Equation
Returns
-------
DataFrame
"""
if not self._is_dirty:
return self._records
self.container._run()
return self._records
@records.setter
def records(self, records):
if records is not None:
if not isinstance(records, pd.DataFrame):
raise TypeError("Symbol 'records' must be type DataFrame")
# set records
self._records = records
self._requires_state_check = True
self.modified = True
self.container._requires_state_check = True
self.container.modified = True
if self._records is not None:
if self.domain_forwarding: # pragma: no cover
self._domainForwarding()
# reset state check flags for all symbols in the container
for symbol in self.container.data.values():
symbol._requires_state_check = True
[docs] def setRecords(self, records: Any, uels_on_axes: bool = False) -> None:
super().setRecords(records, uels_on_axes)
self.container._run()
@property
def type(self):
"""
The type of equation;
3. 'regular' -- equal, less than or greater than
4. 'nonbinding', 'N', or '=N=' -- nonbinding relationship
5. 'cone', 'C', or '=C=' -- cone equation
6. 'external', 'X', or '=X=' -- external equation
7. 'boolean', 'B', or '=B=' -- boolean equation
Returns
-------
str
The type of equation
"""
return self._type
@type.setter
def type(self, eq_type: str | EquationType):
given_type = cast_type(eq_type)
gt.Equation.type.fset(self, given_type)
[docs] def gamsRepr(self) -> str:
"""
Representation of this Equation in GAMS language.
Returns
-------
str
"""
return self.name
[docs] def getStatement(self) -> str:
"""
Statement of the Equation declaration
Returns
-------
str
"""
output = f"Equation {self.name}"
if self.domain:
output += self._get_domain_str()
if self.description:
output += ' "' + self.description + '"'
output += ";"
return output
def cast_type(type: str | EquationType) -> str:
if isinstance(type, str):
if type.lower() not in [
"eq",
"geq",
"leq",
"regular",
"nonbinding",
"external",
"cone",
"boolean",
]:
raise ValueError(
"Allowed equation types:"
f" {EquationType.values()} but found {type}."
)
# assign eq by default
if type.upper() == "REGULAR":
type = "eq"
elif isinstance(type, EquationType):
# assign eq by default
type = "eq" if type == EquationType.REGULAR else str(type)
return type
