FordFulkersonAlgorithm

FordFulkersonAlgorithm#

class FordFulkersonAlgorithm#

Bases: Algorithm[FlowNetwork, FordFulkersonGraphSize, FlowNetwork]

Ford-Fulkerson’s algorithm for finding the maximum flow within a flow network.

__init__()#

Methods

__init__()

get_worst_case_arguments(input_size)

Generate a flow network with input_size.edges edges which will be a line graph of input_size.max_capacity edges with one bottleneck split-merge section.

increment_n_ops([increment])

Convenience method to increment n_ops count of the given complexity object.

reset_n_ops()

Convenience method to reset n_ops count of the given complexity object.

run_algorithm(input_instance[, ...])

Run function of Ford-Fulkerson's maximum flow algorithm.

Attributes

property algorithm_family: AlgorithmFamily#
Return type:

AlgorithmFamily

property algorithm_properties: AlgorithmProperties#
Return type:

AlgorithmProperties

property average_case_time_complexity: str#
Return type:

str

property best_case_description: str#
Return type:

str

property best_case_time_complexity: str#
Return type:

str

get_worst_case_arguments(input_size)#

Generate a flow network with input_size.edges edges which will be a line graph of input_size.max_capacity edges with one bottleneck split-merge section.

Parameters:

input_size (FordFulkersonGraphSize) – Tuple of n_edges, max_capacity with desired flow network size and maximum edge capacity. Number of edges is expected to be at least 5 and the network will have (n_edges - 1) nodes.

Returns:

run_algorithm_kwargs – A dictionary with the created flow network as ‘input_instance’ value, which also stores the source and sink nodes as the first and last node in the chain.

Return type:

dict[str, Any]

increment_n_ops(increment=1)#

Convenience method to increment n_ops count of the given complexity object.

Return type:

None

property is_deterministic: bool#
Return type:

bool

property n_ops: int#
Return type:

int

property name: str#
Return type:

str

reset_n_ops()#

Convenience method to reset n_ops count of the given complexity object.

Return type:

None

run_algorithm(input_instance, verbosity_level=0, find_initial_feasible=True, *args, **kwargs)#

Run function of Ford-Fulkerson’s maximum flow algorithm.

Parameters:
  • input_instance (FlowNetwork[Node]) – Flow network within which to find the maximum flow. Also stores source and sink values.

  • verbosity_level (int (default 0)) – Select the amount of information to print throughout run of the algorithm. One of 0, 1, 2 with 0 referring to no printing, 1 leading to print the flow in the beginning and in the end and 2 meaning also print the maximum flow after each augmentation along with the augmentation path found.

  • find_initial_feasible (bool (default True)) – If True, start the algorithm by finding an initial feasible flow. Initial feasible flow is a prerequisite for the Ford-Fulkerson’s algorithm and if this parameter is set to False, it is assumed that the input_instance FlowNetwork object already has a feasible flow assigned to it. If that is not the case, setting this to False may lead to incorrect results.

  • *args (Any) – Additional arguments passed to the algorithm.

  • **kwargs (Any) – Additional keyword arguments passed to the algorithm.

Returns:

result – Returns True in the first index after termination (always terminates with integer capacities) and FlowNetwork with all edge flows set in the second index.

Return type:

tuple[bool, FlowNetwork[Node]]

property space_complexity: str#
Return type:

str

property worst_case_description: str#
Return type:

str

property worst_case_time_complexity: str#
Return type:

str