Variables

Summary

`pyomo.core.kernel.variable.variable`([...])	A decision variable
`pyomo.core.kernel.variable.variable_tuple`(...)	A tuple-style container for objects with category type IVariable
`pyomo.core.kernel.variable.variable_list`(...)	A list-style container for objects with category type IVariable
`pyomo.core.kernel.variable.variable_dict`(...)	A dict-style container for objects with category type IVariable

Member Documentation

class pyomo.core.kernel.variable.variable(domain_type=None, domain=None, lb=None, ub=None, value=None, fixed=False)[source]

Bases: IVariable

A decision variable

Decision variables are used in objectives and constraints to define an optimization problem.

Parameters:

domain_type – Sets the domain type of the variable. Must be one of RealSet or IntegerSet. Can be updated later by assigning to the domain_type property. The default value of None is equivalent to RealSet, unless the domain keyword is used.
domain – Sets the domain of the variable. This updates the domain_type, lb, and ub properties of the variable. The default value of None implies that this keyword is ignored. This keyword can not be used in combination with the domain_type keyword.
lb – Sets the lower bound of the variable. Can be updated later by assigning to the lb property on the variable. Default is None, which is equivalent to -inf.
ub – Sets the upper bound of the variable. Can be updated later by assigning to the ub property on the variable. Default is None, which is equivalent to +inf.
value – Sets the value of the variable. Can be updated later by assigning to the value property on the variable. Default is None.
fixed (bool) – Sets the fixed status of the variable. Can be updated later by assigning to the fixed property or by calling the fix() method. Default is False.

Examples

>>> import pyomo.kernel as pmo
>>> # A continuous variable with infinite bounds
>>> x = pmo.variable()
>>> # A binary variable
>>> x = pmo.variable(domain=pmo.Binary)
>>> # Also a binary variable
>>> x = pmo.variable(domain_type=pmo.IntegerSet, lb=0, ub=1)

property domain: Set the domain of the variable. This method updates the domain_type property and overwrites the lb and ub properties with the domain bounds.