Public Member Functions | Protected Member Functions | Protected Attributes

CPolyMatchWordStringKernel Class Reference


Detailed Description

The class PolyMatchWordStringKernel computes a variant of the polynomial kernel on word-features.

It makes sense for strings of same length mapped to word features and is computed as

\[ k({\bf x},{\bf x'})= (\sum_{i=0}^L I(x_i=x'_i)+c)^d \]

where I is the indicator function which evaluates to 1 if its argument is true and to 0 otherwise.

Note that additional normalisation is applied, i.e.

\[ k'({\bf x}, {\bf x'})=\frac{k({\bf x}, {\bf x'})}{\sqrt{k({\bf x}, {\bf x})k({\bf x'}, {\bf x'})}} \]

Definition at line 38 of file PolyMatchWordStringKernel.h.

Inheritance diagram for CPolyMatchWordStringKernel:
Inheritance graph
[legend]

List of all members.

Public Member Functions

 CPolyMatchWordStringKernel ()
 CPolyMatchWordStringKernel (int32_t size, int32_t degree, bool inhomogene)
 CPolyMatchWordStringKernel (CStringFeatures< uint16_t > *l, CStringFeatures< uint16_t > *r, int32_t degree, bool inhomogene)
virtual ~CPolyMatchWordStringKernel ()
virtual bool init (CFeatures *l, CFeatures *r)
virtual void cleanup ()
virtual EKernelType get_kernel_type ()
virtual const char * get_name () const

Protected Member Functions

virtual float64_t compute (int32_t idx_a, int32_t idx_b)

Protected Attributes

int32_t degree
bool inhomogene

Constructor & Destructor Documentation

default constructor

Definition at line 20 of file PolyMatchWordStringKernel.cpp.

CPolyMatchWordStringKernel ( int32_t  size,
int32_t  degree,
bool  inhomogene 
)

constructor

Parameters:
size cache size
degree degree
inhomogene is inhomogeneous

Definition at line 26 of file PolyMatchWordStringKernel.cpp.

CPolyMatchWordStringKernel ( CStringFeatures< uint16_t > *  l,
CStringFeatures< uint16_t > *  r,
int32_t  degree,
bool  inhomogene 
)

constructor

Parameters:
l features of left-hand side
r features of right-hand side
degree degree
inhomogene is inhomogeneous

Definition at line 35 of file PolyMatchWordStringKernel.cpp.

~CPolyMatchWordStringKernel (  )  [virtual]

Definition at line 47 of file PolyMatchWordStringKernel.cpp.


Member Function Documentation

void cleanup (  )  [virtual]

clean up kernel

Reimplemented from CKernel.

Definition at line 58 of file PolyMatchWordStringKernel.cpp.

float64_t compute ( int32_t  idx_a,
int32_t  idx_b 
) [protected, virtual]

compute kernel function for features a and b idx_{a,b} denote the index of the feature vectors in the corresponding feature object

Parameters:
idx_a index a
idx_b index b
Returns:
computed kernel function at indices a,b

Implements CKernel.

Definition at line 63 of file PolyMatchWordStringKernel.cpp.

virtual EKernelType get_kernel_type (  )  [virtual]

return what type of kernel we are

Returns:
kernel type POLYMATCH

Implements CStringKernel< uint16_t >.

Definition at line 78 of file PolyMatchWordStringKernel.h.

virtual const char* get_name ( void   )  const [virtual]

return the kernel's name

Returns:
name PolyMatchWord

Reimplemented from CStringKernel< uint16_t >.

Definition at line 84 of file PolyMatchWordStringKernel.h.

bool init ( CFeatures l,
CFeatures r 
) [virtual]

initialize kernel

Parameters:
l features of left-hand side
r features of right-hand side
Returns:
if initializing was successful

Reimplemented from CStringKernel< uint16_t >.

Definition at line 52 of file PolyMatchWordStringKernel.cpp.


Member Data Documentation

int32_t degree [protected]

degree

Definition at line 102 of file PolyMatchWordStringKernel.h.

bool inhomogene [protected]

if kernel is inhomogeneous

Definition at line 104 of file PolyMatchWordStringKernel.h.


The documentation for this class was generated from the following files:
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Defines

SHOGUN Machine Learning Toolbox - Documentation