VarData

(class from pyomo.core.base.var)

class pyomo.core.base.var.VarData(component=None)

Bases: ComponentData, NumericValue

This class defines the data for a single variable.

__init__(component=None)

Methods

__init__([component])
clear()
clear_suffix_value(suffix_or_name[, expand])	Set the suffix value for this component data
cname(*args, **kwds)	DEPRECATED.
copy(src)
fix([value, skip_validation])	Fix the value of this variable (treat as nonvariable)
free()	Alias for unfix()
get_suffix_value(suffix_or_name[, default])	Get the suffix value for this component data
get_units()	Return the units for this variable entry.
getname([fully_qualified, name_buffer, ...])	Return a string with the component name and index
has_lb()	Returns False when the lower bound is None or negative infinity
has_ub()	Returns False when the upper bound is None or positive infinity
index()	Returns the index of this ComponentData instance relative to the parent component index set.
is_binary()	Returns True when the domain is restricted to Binary values.
is_component_type()	Return True if this class is a Pyomo component
is_constant()	Returns False because this is not a constant in an expression.
is_continuous()	Returns True when the domain is a continuous real range
is_expression_type([expression_system])	Return True if this numeric value is an expression
is_fixed()	Returns True if this variable is fixed, otherwise returns False.
is_indexed()	Return true if this component is indexed
is_integer()	Returns True when the domain is a contiguous integer range.
is_logical_type()	Return True if this class is a Pyomo Boolean object.
is_named_expression_type()	Return True if this numeric value is a named expression
is_numeric_type()	Return True if this class is a Pyomo numeric object
is_parameter_type()	Return False unless this class is a parameter object
is_potentially_variable()	Returns True because this is a variable.
is_reference()	Return True if this object is a reference.
is_relational()	DEPRECATED.
is_variable_type()	Returns True because this is a variable.
model()	Return the model of the component that owns this data.
parent_block()	Return the parent of the component that owns this data.
parent_component()	Returns the component associated with this object.
polynomial_degree()	Return the polynomial degree of the expression.
pprint([ostream, verbose, prefix])	Print component information
set_suffix_value(suffix_or_name, value[, expand])	Set the suffix value for this component data
set_value(val[, skip_validation])	Set the current variable value.
setlb(val)	Set the lower bound for this variable after validating that the value is fixed (or None).
setub(val)	Set the upper bound for this variable after validating that the value is fixed (or None).
to_string([verbose, labeler, smap, ...])	Return a string representation of the expression tree.
type()	DEPRECATED.
unfix()	Unfix this variable (treat as variable in solver interfaces)

Attributes

active	Return the active attribute
bounds	Returns (or set) the tuple (lower bound, upper bound).
ctype	Return the class type for this component
domain	Return (or set) the domain for this variable.
fixed	Return (or set) the fixed indicator for this variable.
lb	Return (or set) the numeric value of the variable lower bound.
local_name	Get the component name only within the context of the immediate parent container.
lower	Return (or set) an expression for the variable lower bound.
name	Get the fully qualified component name.
stale	The stale status for this variable.
ub	Return (or set) the numeric value of the variable upper bound.
upper	Return (or set) an expression for the variable upper bound.
value	Return (or set) the value for this variable.

Member Documentation

clear_suffix_value(suffix_or_name, expand=True)

Set the suffix value for this component data

cname(*args, **kwds)

DEPRECATED.

Deprecated since version 5.0: The cname() method has been renamed to getname(). The preferred method of obtaining a component name is to use the .name property, which returns the fully qualified component name. The .local_name property will return the component name only within the context of the immediate parent container.

fix(value=NOTSET, skip_validation=False)

Fix the value of this variable (treat as nonvariable)

This sets the fixed indicator to True. If value is provided, the value (and the skip_validation flag) are first passed to set_value().

free()

Alias for unfix()

get_suffix_value(suffix_or_name, default=None)

Get the suffix value for this component data

get_units()

Return the units for this variable entry.

getname(fully_qualified=False, name_buffer=None, relative_to=None)

Return a string with the component name and index

has_lb()

Returns False when the lower bound is None or negative infinity

has_ub()

Returns False when the upper bound is None or positive infinity

index()

Returns the index of this ComponentData instance relative to the parent component index set. None is returned if this instance does not have a parent component, or if - for some unknown reason - this instance does not belong to the parent component’s index set.

is_binary()

Returns True when the domain is restricted to Binary values.

is_component_type()

Return True if this class is a Pyomo component

is_constant()

Returns False because this is not a constant in an expression.

is_continuous()

Returns True when the domain is a continuous real range

is_expression_type(expression_system=None)

Return True if this numeric value is an expression

is_fixed()

Returns True if this variable is fixed, otherwise returns False.

is_indexed()

Return true if this component is indexed

is_integer()

Returns True when the domain is a contiguous integer range.

is_logical_type()

Return True if this class is a Pyomo Boolean object.

Boolean objects include constants, variables, or logical expressions.

is_named_expression_type()

Return True if this numeric value is a named expression

is_numeric_type()

Return True if this class is a Pyomo numeric object

is_parameter_type()

Return False unless this class is a parameter object

is_potentially_variable()

Returns True because this is a variable.

is_reference()

Return True if this object is a reference.

is_relational()

DEPRECATED.

Return True if this numeric value represents a relational expression.

Deprecated since version 6.4.3: is_relational() is deprecated in favor of is_expression_type(ExpressionType.RELATIONAL)

is_variable_type()

Returns True because this is a variable.

model()

Return the model of the component that owns this data.

parent_block()

Return the parent of the component that owns this data.

parent_component()

Returns the component associated with this object.

polynomial_degree()

Return the polynomial degree of the expression.

Returns:

None

pprint(ostream=None, verbose=False, prefix='')

Print component information

Note that this method is generally only reachable through ComponentData objects in an IndexedComponent container. Components, including unindexed Component derivatives and both scalar and indexed IndexedComponent derivatives will see Component.pprint()

set_suffix_value(suffix_or_name, value, expand=True)

Set the suffix value for this component data

set_value(val, skip_validation=False)

Set the current variable value.

Set the value of this variable. The incoming value is converted to a numeric value (i.e., expressions are evaluated). If the variable has units, the incoming value is converted to the correct units before storing the value. The final value is checked against both the variable domain and bounds, and an exception is raised if the value is not valid. Domain and bounds checking can be bypassed by setting the skip_validation argument to True.

setlb(val)

Set the lower bound for this variable after validating that the value is fixed (or None).

setub(val)

Set the upper bound for this variable after validating that the value is fixed (or None).

to_string(verbose=None, labeler=None, smap=None, compute_values=False)

Return a string representation of the expression tree.

Parameters:

• verbose (bool) – If True, then the string representation consists of nested functions. Otherwise, the string representation is an infix algebraic equation. Defaults to False.

• labeler – An object that generates string labels for non-constant in the expression tree. Defaults to None.

• smap – A SymbolMap instance that stores string labels for non-constant nodes in the expression tree. Defaults to None.

• compute_values (bool) – If True, then fixed expressions are evaluated and the string representation of the resulting value is returned.

Returns:

A string representation for the expression tree.

type()

DEPRECATED.

Return the class type for this component

Deprecated since version 5.7: Component.type() method has been replaced by the .ctype property.

unfix()

Unfix this variable (treat as variable in solver interfaces)

This sets the fixed indicator to False.

property active

Return the active attribute

property bounds

Returns (or set) the tuple (lower bound, upper bound).

This returns the current (numeric) values of the lower and upper bounds as a tuple. If there is no bound, returns None (and not +/-inf)

property ctype

Return the class type for this component

property domain

Return (or set) the domain for this variable.

property fixed

Return (or set) the fixed indicator for this variable.

Alias for is_fixed() / fix() / unfix().

property lb

Return (or set) the numeric value of the variable lower bound.

property local_name

Get the component name only within the context of the immediate parent container.

property lower

Return (or set) an expression for the variable lower bound.

This returns a (not potentially variable) expression for the variable lower bound. This represents the tighter of the current domain and the constant or expression assigned to lower. Note that the expression will NOT automatically reflect changes to either the domain or the bound expression (e.g., because of assignment to either lower or domain).

property name

Get the fully qualified component name.

property stale

The stale status for this variable.

Variables are “stale” if their current value was not updated as part of the most recent model update. A “model update” can be one of several things: a solver invocation, loading a previous solution, or manually updating a non-stale Var value.

Return type:

bool

Notes

Fixed Var objects will be stale after invoking a solver (as their value was not updated by the solver).

Updating a stale Var value will not cause other variable values to be come stale. However, updating the first non-stale Var value after a solve or solution load will cause all other variables to be marked as stale

property ub

Return (or set) the numeric value of the variable upper bound.

property upper

Return (or set) an expression for the variable upper bound.

This returns a (not potentially variable) expression for the variable upper bound. This represents the tighter of the current domain and the constant or expression assigned to upper. Note that the expression will NOT automatically reflect changes to either the domain or the bound expression (e.g., because of assignment to either upper or domain).

property value

Return (or set) the value for this variable.