#include "warping.h"
#include "optarg.h"
#include "array.h"
#include "linalg.h"
#include "eeg.h"
#include <math.h>

Functions
Array *	dtw_add_signals (const Array s1, const Array s2, const Array path, OptArgList opts)
	Add signals according to a warppath.
WarpPath *	dtw_backtrack (const double *d, int M, int N, WarpPath P)
void	dtw_cumulate_matrix (double *d, int M, int N, OptArgList optargs)
EEG *	eeg_gibbons (EEG *eeg, int stimulus_marker, int response_marker, double k)
void	free_warppath (WarpPath *p)
WarpPath *	init_warppath (WarpPath *path, int n1, int n2)
Array *	matrix_dtw_backtrack (const Array *d)
	calculate the warping path.
Array *	matrix_dtw_cumulate (Array mat, bool alloc, OptArgList optargs)
	cumulate a distance matrix d for Dynamic Time-Warping.
void	print_warppath (FILE out, WarpPath P)
void	reset_warppath (WarpPath *P, int n1, int n2)

Function Documentation

WarpPath* dtw_backtrack	(	const double **	d,
		int	M,
		int	N,
		WarpPath *	P
	)

Definition at line 526 of file warping.c.

void dtw_cumulate_matrix	(	double **	d,
		int	M,
		int	N,
		OptArgList *	optargs
	)

cumulate a distance matrix d to give

$D_{jk} = d_{jk}+\min{\{D_{j,k-1}, D_{j-1,k}, D_{j-1, k-1}\}}$

Parameters:

d

input/output matrix

M,N

dimensions of d

optargs

may contain:

"slope_constraint=int" slope constraint, one of SLOPE_CONSTRAINT_*; default=SLOPE_CONSTRAINT_NONE

Definition at line 488 of file warping.c.

EEG* eeg_gibbons	(	EEG *	eeg,
		int	stimulus_marker,
		int	response_marker,
		double	k
	)

Warp-average according to Gibbons+Stahl 2007. They proposed to stretch or compress the single signals in order to match the average reaction time, by simply moving the sampling points in time according to a linear, quadratic, cubic or to-the-power-of-four function. Formally, they adjusted the time-axis by letting

$\phi_t^{-1}(t) = t + \frac{t^k}{R^k_t}(E(R) - R_t)$

where $ R_t $ denotes the reaction time of the current trial and E is the expected value (the mean reaction time across trials). In their work, Gibbons et al. studied this approach for $k \in \{1,2,3,4\}$ .

Individual trials are warped according to $\phi$ and also the averages obtained from different individuals. Warping takes place between stimulus-onset-marker and response-marker

Parameters:

	eeg_in	input
	stmulus_marker	gives the index indicating which of the markers within eeg_in is the stimulus-onset
	response_marker	gives the index indicating which of the markers within eeg_in is the response-onset
	k	parameter for gibbon's method

Returns:: pointer to newly allocated memory

Definition at line 318 of file warping.c.

void free_warppath ( WarpPath * p )

Definition at line 450 of file warping.c.

WarpPath* init_warppath	(	WarpPath *	path,
		int	n1,
		int	n2
	)

Definition at line 419 of file warping.c.

void print_warppath	(	FILE *	out,
		WarpPath *	P
	)

Definition at line 456 of file warping.c.

void reset_warppath	(	WarpPath *	P,
		int	n1,
		int	n2
	)

Definition at line 441 of file warping.c.

src/warping.c File Reference

Functions

Function Documentation