AlphaExpansion< T > Class Template Reference

Performs alpha-expansion moves on an EnergyModel using a pluggable max-flow solver. More...

#include <AlphaExpansion.hpp>

Public Types
using	SolverFactory = std::function< std::unique_ptr< MaxFlowSolver< T > >(int num_vars, int num_edges)>

Public Member Functions
	AlphaExpansion (EnergyModel< T > &model, SolverFactory solver_factory)
	Constructs the optimizer.
bool	perform_expansion_move (const int alpha_label) const
	Attempts a single alpha-expansion move for alpha_label.

Detailed Description

template<typename T>
class AlphaExpansion< T >

Performs alpha-expansion moves on an EnergyModel using a pluggable max-flow solver.

An AlphaExpansion object holds a reference to an EnergyModel and a factory function that creates a new MaxFlowSolver for each expansion move. The model must outlive the optimizer, so do not destroy the model while the optimizer is still being used.

The optimizer is usually driven by an ExpansionStrategy, which decides the order of label expansions and when to stop.

Template Parameters

T	Numeric cost type. Must match the type of the associated EnergyModel<T>.

Member Typedef Documentation

SolverFactory

template<typename T >

using AlphaExpansion< T >::SolverFactory = std::function<std::unique_ptr<MaxFlowSolver<T> >(int num_vars, int num_edges)>

Factory function that creates a new solver instance.

Parameters

num_vars	Number of binary variables (active nodes in the expansion subgraph).
num_edges	Estimated number of edges (used for pre-allocation; may be exceeded).

Constructor & Destructor Documentation

AlphaExpansion()

template<typename T >

AlphaExpansion< T >::AlphaExpansion ( EnergyModel< T > &  model, SolverFactory  solver_factory  )

inline

Constructs the optimizer.

Parameters

model	Energy model to optimize. Must outlive this object.
solver_factory	Factory used to create a fresh solver for each expansion move.

Member Function Documentation

perform_expansion_move()

template<typename T >

bool AlphaExpansion< T >::perform_expansion_move ( const int  alpha_label ) const

inline

Attempts a single alpha-expansion move for alpha_label.

Builds the binary subgraph for alpha_label and runs max-flow. If the resulting label assignment reduces the total energy, it is applied to the model.

Parameters

alpha_label

The label to expand (0 ≤ alpha_label < num_labels).

Returns

true if any node's label changed and energy decreased; false otherwise.

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The documentation for this class was generated from the following file:

• src/core/AlphaExpansion.hpp