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Set Packing API Reference

Data

Data model for SetPacking use case.

SetPackingData

Bases: UcData

Data for the Set Packing Problem.

Given a universe of elements, a collection of subsets, and weights per subset, the Set Packing problem asks to find the maximum-weight collection of pairwise disjoint subsets.

Attributes:

Name Type Description
name Literal['set_packing']

Identifier for this data type.

subset_matrix list[list[int]]

A matrix where each row represents a subset and each column an element. subset_matrix[i][j] = 1 if subset i contains element j, 0 otherwise.

weights list[float]

Weight (value) associated with each subset.

plot(*, ax: Axes | None = None) -> Axes

Plot the subset matrix as a binary heatmap with weights.

Parameters:

Name Type Description Default
ax Axes | None

Matplotlib axes to draw on. Creates a new figure if None.

None

Returns:

Type Description
Axes

The axes with the plot.

to_string() -> str

Return a string describing the data.

Returns:

Type Description
str

String representation of the data.

from_values(subset_matrix: list[list[int]], weights: list[float]) -> SetPackingData staticmethod

Create a SetPackingData instance from explicit values.

Parameters:

Name Type Description Default
subset_matrix list[list[int]]

A matrix where each row represents a subset and each column an element. subset_matrix[i][j] = 1 if subset i contains element j, 0 otherwise.

required
weights list[float]

Weight (value) associated with each subset.

required

Returns:

Type Description
SetPackingData

A SetPackingData instance with the given values.

generate_random(n_elements: int = 5, n_subsets: int = 8, density: float = 0.3, seed: int | None = None) -> SetPackingData staticmethod

Generate a random set packing instance.

Parameters:

Name Type Description Default
n_elements int

Number of elements in the universe, by default 5.

5
n_subsets int

Number of subsets, by default 8.

8
density float

Probability that an element is included in a subset, by default 0.3.

0.3
seed int | None

Random seed for reproducibility, by default None.

None

Returns:

Type Description
SetPackingData

A randomly generated set packing instance.

Formulation

Formulation for SetPacking use case.

SetPackingFormulation

Bases: UcFormulation[SetPackingData, SetPackingSolution]

Constraint-based formulation for the Set Packing Problem.

Mathematical Formulation
Decision Variables:
    x_s in {0,1} for each subset s: 1 if subset s is selected

Objective:
    maximize sum_s weights[s] * x_s

Constraints:
    For each element e:
        sum_{s containing e} x_s <= 1
    (each element can be in at most one selected subset)

to_string(data: SetPackingData) -> str staticmethod

Return a string describing the formulation.

Parameters:

Name Type Description Default
data SetPackingData

The problem data.

required

Returns:

Type Description
str

String representation of the formulation.

formulate(data: SetPackingData) -> Model staticmethod

Formulate the Set Packing Problem using constraint-based approach.

Parameters:

Name Type Description Default
data SetPackingData

The Set Packing instance data.

required

Returns:

Type Description
Model

A LunaModel ready to be solved.

interpret(solution: Solution, data: SetPackingData) -> SetPackingSolution staticmethod

Extract solution from quantum result.

Parameters:

Name Type Description Default
solution Solution

The quantum solution.

required
data SetPackingData

The problem data.

required

Returns:

Type Description
SetPackingSolution

Structured solution with metrics.

Solution

Solution model for SetPacking use case.

SetPackingSolution

Bases: UcSolution

Solution for the Set Packing Problem.

Attributes:

Name Type Description
name Literal['set_packing']

Identifier for this solution type.

selected_subsets list[int]

Indices of selected subsets.

total_weight float

Total weight of selected subsets.

is_valid bool

Whether selected subsets are pairwise disjoint.

plot(data: SetPackingData | None = None, *, ax: Axes | None = None) -> Axes

Plot the set packing solution.

Parameters:

Name Type Description Default
data SetPackingData | None

Problem data for context.

None
ax Axes | None

Matplotlib axes to draw on. Creates a new figure if None.

None

Returns:

Type Description
Axes

The axes with the plot.

to_string() -> str

Return a string describing the solution.

Returns:

Type Description
str

String representation of the solution.

Instance

Instance model for SetPacking use case.

SetPackingInstance

Bases: UcInstance[SetPackingData, SetPackingFormulation, SetPackingSolution]

Instance combining data and formulation for SetPacking.

Collection

Collection of SetPacking instances.

SetPackingCollection

Bases: UcInstanceCollection[SetPackingInstance]

Collection of Set Packing instances.

This collection provides methods to generate benchmark instances with various characteristics for testing and evaluation.

from_random(min_num_elements: int | None = None, max_num_elements: int | None = None, num_instances: int = 1, *, sizes: Sequence[int] | None = None, density: float = 0.3, subset_ratio: float = 1.6, seed: int | None = None) -> SetPackingCollection classmethod

Generate random set packing instances.

Parameters:

Name Type Description Default
min_num_elements int | None

Minimum number of elements per instance.

None
max_num_elements int | None

Maximum number of elements per instance.

None
num_instances int

Number of instances per size, by default 1.

1
density float

Probability that an element is included in a subset, by default 0.3.

0.3
subset_ratio float

Ratio of subsets to elements, by default 1.6.

1.6
seed int | None

Random seed for reproducibility, by default None.

None
sizes Sequence[int] | None

Explicit sizes to generate, e.g. [10, 50, 100], instead of a range. Mutually exclusive with min_num_elements/max_num_elements, by default None.

None

Returns:

Type Description
SetPackingCollection

Collection containing generated instances.

filter_infeasible(max_runtime: float = 3600, *, quiet: bool = True) -> list[bool]

Drop the instances of this collection that have no feasible solution.

Every instance is formulated and handed to SCIP, which stops as soon as it finds the first feasible solution. An instance is removed from the collection when SCIP proves the model infeasible, when no solution turns up within max_runtime, or when formulating it fails altogether. This keeps randomly generated instances from breaking a downstream pipeline.

Parameters:

Name Type Description Default
max_runtime float

SCIP time limit per instance in seconds. Must be positive. Defaults to 3600 seconds.

3600
quiet bool

Suppress the SCIP solver output.

True

Returns:

Type Description
list[bool]

Feasibility mask over the instances as they were before filtering, in that order: True where the instance was kept, False where it was removed.

Raises:

Type Description
ValueError

If max_runtime is not positive.