homkermap.h File Reference

Homogeneous kernel map (Homogeneous kernel map) More...

#include "generic.h"
#include <math.h>

Data Structures
struct	VlHomogeneousKernelMap
	Homogeneous kernel map. More...
Enumerations
enum	VlHomogeneousKernelType { VlHomogeneousKernelIntersection = 0, VlHomogeneousKernelChi2, VlHomogeneousKernelJS }
	Type of kernel. More...
enum	VlHomogeneousKernelMapWindowType { VlHomogeneousKernelMapWindowUniform = 0, VlHomogeneousKernelMapWindowRectangular = 1 }
	Type of spectral windowing function. More...
Functions
VlHomogeneousKernelMap *	vl_homogeneouskernelmap_new (VlHomogeneousKernelType kernelType, double gamma, vl_size order, double period, VlHomogeneousKernelMapWindowType windowType)
	Create a new homgeneous kernel map.
void	vl_homogeneouskernelmap_delete (VlHomogeneousKernelMap *self)
	Delete a map object.
void	vl_homogeneouskernelmap_evaluate_d (VlHomogeneousKernelMap const *self, double *destination, vl_size stride, double x)
	Evaluate map.
void	vl_homogeneouskernelmap_evaluate_f (VlHomogeneousKernelMap const *self, float *destination, vl_size stride, double x)
	Evaluate map.

---

Detailed Description

Author:

Andrea Vedaldi

---

Enumeration Type Documentation

enum VlHomogeneousKernelMapWindowType

Enumerator:

VlHomogeneousKernelMapWindowUniform	uniform window
VlHomogeneousKernelMapWindowRectangular	rectangular window

enum VlHomogeneousKernelType

Enumerator:

VlHomogeneousKernelIntersection	intersection kernel
VlHomogeneousKernelChi2	Chi2 kernel
VlHomogeneousKernelJS	Jensen-Shannon kernel

---

Function Documentation

void vl_homogeneouskernelmap_delete

(

VlHomogeneousKernelMap *

self

)

Parameters:

self	map object. The function deletes the specified map object.

vl_homogeneouskernelmap_evaluate_d	(	VlHomogeneousKernelMap const *	self,
		double *	destination,
		vl_size	stride,
		double	x
	)

Parameters:

self	map object.
destination	output buffer.
stride	stride of the output buffer.
x	value to expand.

The function evaluates the feature map on x and stores the resulting 2*order+1 dimensional vector to destination[0], destination[stride], destination[2*stride], ....

vl_homogeneouskernelmap_evaluate_f	(	VlHomogeneousKernelMap const *	self,
		float *	destination,
		vl_size	stride,
		double	x
	)

Parameters:

self	map object.
destination	output buffer.
stride	stride of the output buffer.
x	value to expand.

The function evaluates the feature map on x and stores the resulting 2*order+1 dimensional vector to destination[0], destination[stride], destination[2*stride], ....

VlHomogeneousKernelMap* vl_homogeneouskernelmap_new	(	VlHomogeneousKernelType	kernelType,
		double	gamma,
		vl_size	order,
		double	period,
		VlHomogeneousKernelMapWindowType	windowType
	)

Parameters:

kernelType	type of homogeneous kernel.
gamma	kernel homogeneity degree.
order	approximation order.
period	kernel period.
windowType	type of window used to truncate the kernel.

Returns:

the new homogeneous kernel map.

The function intializes a new homogeneous kernel map for the specified kernel type, homogeneity degree, approximation order, period, and truncation window. See Overview for details.

The homogeneity degree gamma must be positive (the standard kernels are obtained by setting gamma to 1). When unsure, set windowType to VlHomogeneousKernelMapWindowRectangular. The period should be non-negative; specifying a negative or null value causes the function to switch to a default value.

The function returns NULL if there is not enough free memory.