meta::sequence::viterbi_trellis Class Reference

Special trellis for the Viterbi algorithm. More...

#include <trellis.h>

Inheritance diagram for meta::sequence::viterbi_trellis:

Public Member Functions
	viterbi_trellis (uint64_t size, uint64_t labels)
	Constructs a viterbi_trellis with the given number of time steps and labels. More...
void	previous_tag (uint64_t idx, const label_id &current, const label_id &previous)
	Sets the back pointer for the given time step and label to the given label. More...
const label_id &	previous_tag (uint64_t idx, const label_id &current) const
Public Member Functions inherited from meta::sequence::trellis
	trellis (uint64_t size, uint64_t labels)
	Constructs a new trellis with the given number of time steps and labels. More...
uint64_t	size () const
void	probability (uint64_t idx, const label_id &tag, double prob)
	Sets the value in the trellis for the given time step and label. More...
double	probability (uint64_t idx, const label_id &tag) const
	Obtains the value in the trellis for the given time step and label. More...

Private Attributes
util::dense_matrix< label_id >	paths_
	storage for the back pointers

Additional Inherited Members
Protected Attributes inherited from meta::sequence::trellis
util::dense_matrix< double >	trellis_
	storage for the scores

Detailed Description

Special trellis for the Viterbi algorithm.

In addition to storing the scores like a normal trellis, it also can store back pointers indicating the best possible path for each node at each time step.

Constructor & Destructor Documentation

meta::sequence::viterbi_trellis::viterbi_trellis	(	uint64_t	size,
		uint64_t	labels
	)

Constructs a viterbi_trellis with the given number of time steps and labels.

Parameters

size	The number of time steps
labels	The number of labels

Member Function Documentation

void meta::sequence::viterbi_trellis::previous_tag	(	uint64_t	idx,
		const label_id &	current,
		const label_id &	previous
	)

Sets the back pointer for the given time step and label to the given label.

Parameters

idx	The time step
current	The current label
previous	The best previous tag for the current label

const label_id & meta::sequence::viterbi_trellis::previous_tag	(	uint64_t	idx,
		const label_id &	current
	)		const

Parameters

idx	The time step
current	The label

Returns

the back pointer for the given time step and label.

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

• /home/chase/projects/meta/include/sequence/trellis.h
• /home/chase/projects/meta/src/sequence/trellis.cpp