1 core.variable_dict.VariableDict

core.variable_dict.VariableDict(
    name,
    keys,
    lb=None,
    ub=None,
    domain='continuous',
)

A dictionary-keyed collection of optimization variables.

Variables are indexed by string keys (e.g., product names, cities) rather than integer indices. Supports weighted sums, partial sums, and dict-like iteration.

1.1 Parameters

Name	Type	Description	Default
name	str	Base name for all variables. Individual variables are named "{name}[{key}]".	required
keys	Sequence[str]	Sequence of string keys.	required
lb	float | Mapping[str, float] | None	Lower bound — scalar (broadcast to all), or dict (per-key).	None
ub	float | Mapping[str, float] | None	Upper bound — scalar (broadcast to all), or dict (per-key).	None
domain	Literal['continuous', 'integer', 'binary']	Variable domain — 'continuous', 'integer', or 'binary'.	'continuous'

1.2 Example

foods = [“hamburger”, “chicken”, “pizza”, “salad”] buy = VariableDict(“buy”, foods, lb=0) buy[“hamburger”] # Variable(“buy[hamburger]”) buy.sum() # sum of all buy variables buy.prod({“hamburger”: 2.49, “chicken”: 2.89, …}) # weighted sum

1.3 Methods

Name	Description
get_variables	Return all Variable objects in key order.
items	Return (key, variable) pairs.
keys	Return the keys of this VariableDict.
prod	Weighted sum (inner product) of variables with coefficients.
sum	Sum of variables, optionally over a subset of keys.
to_dict	Extract variable values from a solution as a {key: value} dict.
values	Return the variables of this VariableDict.

1.3.1 get_variables

core.variable_dict.VariableDict.get_variables()

Return all Variable objects in key order.

1.3.2 items

core.variable_dict.VariableDict.items()

Return (key, variable) pairs.

1.3.3 keys

core.variable_dict.VariableDict.keys()

Return the keys of this VariableDict.

1.3.4 prod

core.variable_dict.VariableDict.prod(coefficients)

Weighted sum (inner product) of variables with coefficients.

1.3.4.1 Parameters

Name	Type	Description	Default
coefficients	Mapping[str, float] | Sequence[float]	Either a dict mapping keys to coefficients, or a sequence of coefficients in key order.	required

1.3.4.2 Returns

Name	Type	Description
	Expression	Expression representing the weighted sum.

1.3.4.3 Example

cost = {“hamburger”: 2.49, “chicken”: 2.89} buy.prod(cost) # 2.49buy[hamburger] + 2.89buy[chicken] + …

1.3.5 sum

core.variable_dict.VariableDict.sum(keys=None)

Sum of variables, optionally over a subset of keys.

1.3.5.1 Parameters

Name	Type	Description	Default
keys	Sequence[str] | None	If provided, sum only these keys. Otherwise sum all.	None

1.3.5.2 Returns

Name	Type	Description
	Expression	Expression representing the sum.

1.3.5.3 Example

buy.sum() # sum of all buy.sum([“hamburger”, “chicken”]) # partial sum

1.3.6 to_dict

core.variable_dict.VariableDict.to_dict(solution)

Extract variable values from a solution as a {key: value} dict.

This is a convenience wrapper around solution[variable_dict].

1.3.6.1 Parameters

Name	Type	Description	Default
solution	Solution	A :class:~optyx.solution.Solution object.	required

1.3.6.2 Returns

Name	Type	Description
	dict[str, float]	Dict mapping each key to its optimal value.

1.3.7 values

core.variable_dict.VariableDict.values()

Return the variables of this VariableDict.