FMM::MM::TransitionGraph Class Reference

Transition graph class in HMM. More...

#include <transition_graph.hpp>

Public Member Functions
	TransitionGraph (const Traj_Candidates &tc, double gps_error)
	Transition graph constructor. More...
void	reset_layer (TGLayer *layer)
	Reset all the proability data stored in a layer of the transition graph. More...
const TGNode *	find_optimal_candidate (const TGLayer &layer)
	Find the optimal candidate in a layer with the highest accumulative probability. More...
TGOpath	backtrack ()
	Backtrack the transition graph to find an optimal path. More...
std::vector< TGLayer > &	get_layers ()
	Get a reference to the inner layers of the transition graph.

Static Public Member Functions
static double	calc_tp (double sp_dist, double eu_dist)
	Calculate transition probability. More...
static double	calc_ep (double dist, double error)
	Calculate emission probability. More...

Detailed Description

Transition graph class in HMM.

The class stores the underlying transition graph of a HMM, which stores the probabilities of candidates matched to a trajectories.

Definition at line 54 of file transition_graph.hpp.

Constructor & Destructor Documentation

TransitionGraph()

TransitionGraph::TransitionGraph	(	const Traj_Candidates &	tc,
		double	gps_error
	)

Transition graph constructor.

A transition graph is created to store the probability of emission and transition in HMM model where optimal path will be infered.

Parameters

tc	Trajectory candidates
gps_error	GPS error

Definition at line 19 of file transition_graph.cpp.

Member Function Documentation

backtrack()

TGOpath TransitionGraph::backtrack

(

)

Backtrack the transition graph to find an optimal path.

Returns

An optimal path connecting the first layer with last layer and has the highest accumulative probability value.

Definition at line 62 of file transition_graph.cpp.

calc_ep()

double TransitionGraph::calc_ep ( double  dist, double  error  )

static

Calculate emission probability.

Parameters

dist	The actual gps error from observed point to matched point
error	The GPS sensor's accuracy

Returns

emission probability in HMM

Definition at line 37 of file transition_graph.cpp.

calc_tp()

double TransitionGraph::calc_tp ( double  sp_dist, double  eu_dist  )

static

Calculate transition probability.

Parameters

sp_dist	Shortest path distance between two candidates
eu_dist	Euclidean distance between two candidates

Returns

transition probability in HMM

Definition at line 33 of file transition_graph.cpp.

find_optimal_candidate()

const TGNode * TransitionGraph::find_optimal_candidate

(

const TGLayer &

layer

)

Find the optimal candidate in a layer with the highest accumulative probability.

Parameters

layer

[description]

Returns

pointer to the optimal node in the transition graph

Definition at line 50 of file transition_graph.cpp.

reset_layer()

void TransitionGraph::reset_layer

(

TGLayer *

layer

)

Reset all the proability data stored in a layer of the transition graph.

Parameters

layer

A layer in the transition graph

Definition at line 43 of file transition_graph.cpp.

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

• /Users/canyang/Workspace/fmm/src/mm/transition_graph.hpp
• /Users/canyang/Workspace/fmm/src/mm/transition_graph.cpp