liblevenshtein::StateTransition Class Reference

Transitions Levenshtein States given a characteristic vector. More...

#include <state_transition.h>

Collaboration diagram for liblevenshtein::StateTransition:

Public Member Functions
	StateTransition (PositionTransitionFn transition, CompareFn compare, MergeFn merge, UnsubsumeFn unsubsume, std::size_t max_distance, std::size_t query_length)
	Constructs a new StateTransition function.
auto	operator() (State *curr_state, std::vector< bool > &characteristic_vector) -> State *
	Returns a successive State to the current one given the characteristic vector.

Private Attributes
PositionTransitionFn	transition
	Maps Position nodes and characteristic vectors to subsequent Position nodes.
CompareFn	compare
	Compares Position nodes.
MergeFn	merge
	Merges Positions into a State.
UnsubsumeFn	unsubsume
	Removes redundant Positions from a State according to the notion of subsumption.
std::size_t	max_distance
	Maximum edit distance to consider when matching spelling candidates.
std::size_t	query_length
	Length of the query term.

Detailed Description

Transitions Levenshtein States given a characteristic vector.

Definition at line 28 of file state_transition.h.

Constructor & Destructor Documentation

StateTransition()

liblevenshtein::StateTransition::StateTransition	(	PositionTransitionFn	transition,
		CompareFn	compare,
		MergeFn	merge,
		UnsubsumeFn	unsubsume,
		std::size_t	max_distance,
		std::size_t	query_length )

Constructs a new StateTransition function.

Parameters

transition	Maps Position nodes and characteristic vectors to subsequent Position nodes.
compare	Compares Position nodes.
merge	Merges Positions into a State.
unsubsume	Removes redundant Positions from a State according to the notion of subsumption.
max_distance	Maximum edit distance to consider when matching spelling candidates.
query_length	Length of the query term.

Definition at line 8 of file state_transition.cpp.

    : transition(std::move(transition)), compare(std::move(compare)),
      merge(std::move(merge)), unsubsume(std::move(unsubsume)),
      max_distance(max_distance), query_length(query_length) {}

Member Function Documentation

operator()()

auto liblevenshtein::StateTransition::operator()	(	State *	curr_state,
		std::vector< bool > &	characteristic_vector ) -> State *

Returns a successive State to the current one given the characteristic vector.

Parameters

curr_state	Current State in the Levenshtein automaton.
characteristic_vector	Moving window over matching characters in the query term.

Returns

The next state in the Levenshtein automaton.

Definition at line 17 of file state_transition.cpp.

               {
  std::size_t offset = curr_state->head()->term_index();
  auto *next_state = new State();
  std::size_t n = max_distance;
 
  for (Position *position : *curr_state) {
    merge(next_state, transition(n, position, characteristic_vector, offset));
  }
 
  unsubsume(next_state, query_length);
 
  if (next_state->head() != nullptr) {
    next_state->sort(compare);
    return next_state;
  }
 
  delete next_state;
  return nullptr;
}

References liblevenshtein::compare(), liblevenshtein::State::head(), liblevenshtein::merge(), and query().

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Member Data Documentation

compare

CompareFn liblevenshtein::StateTransition::compare

private

Compares Position nodes.

Definition at line 70 of file state_transition.h.

max_distance

std::size_t liblevenshtein::StateTransition::max_distance

private

Maximum edit distance to consider when matching spelling candidates.

Definition at line 80 of file state_transition.h.

merge

MergeFn liblevenshtein::StateTransition::merge

private

Merges Positions into a State.

Definition at line 73 of file state_transition.h.

query_length

std::size_t liblevenshtein::StateTransition::query_length

private

Length of the query term.

Definition at line 83 of file state_transition.h.

transition

PositionTransitionFn liblevenshtein::StateTransition::transition

private

Maps Position nodes and characteristic vectors to subsequent Position nodes.

Definition at line 67 of file state_transition.h.

unsubsume

UnsubsumeFn liblevenshtein::StateTransition::unsubsume

private

Removes redundant Positions from a State according to the notion of subsumption.

Definition at line 77 of file state_transition.h.

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

• src/liblevenshtein/transducer/state_transition.h
• src/liblevenshtein/transducer/state_transition.cpp