Public Member Functions | Protected Member Functions | Protected Attributes

CPolyMatchStringKernel Class Reference

Detailed Description

The class PolyMatchStringKernel computes a variant of the polynomial kernel on strings of same length.

It 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 36 of file PolyMatchStringKernel.h.

Inheritance diagram for CPolyMatchStringKernel:
Inheritance graph

List of all members.

Public Member Functions

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

Protected Member Functions

virtual float64_t compute (int32_t idx_a, int32_t idx_b)

Protected Attributes

int32_t degree
bool inhomogene
bool rescaling

Constructor & Destructor Documentation

default constructor

Definition at line 20 of file PolyMatchStringKernel.cpp.

CPolyMatchStringKernel ( int32_t  size,
int32_t  degree,
bool  inhomogene 


size cache size
degree degree
inhomogene is inhomogeneous

Definition at line 26 of file PolyMatchStringKernel.cpp.

CPolyMatchStringKernel ( CStringFeatures< char > *  l,
CStringFeatures< char > *  r,
int32_t  degree,
bool  inhomogene 


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

Definition at line 35 of file PolyMatchStringKernel.cpp.

~CPolyMatchStringKernel (  )  [virtual]

Definition at line 47 of file PolyMatchStringKernel.cpp.

Member Function Documentation

void cleanup (  )  [virtual]

clean up kernel

Reimplemented from CKernel.

Definition at line 58 of file PolyMatchStringKernel.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

idx_a index a
idx_b index b
computed kernel function at indices a,b

Implements CKernel.

Definition at line 63 of file PolyMatchStringKernel.cpp.

virtual EKernelType get_kernel_type (  )  [virtual]

return what type of kernel we are

kernel type POLYMATCH

Implements CStringKernel< char >.

Definition at line 78 of file PolyMatchStringKernel.h.

virtual const char* get_name (  )  const [virtual]

return the kernel's name

name PolyMatchString

Reimplemented from CStringKernel< char >.

Definition at line 87 of file PolyMatchStringKernel.h.

bool get_rescaling_enabled (  ) 

return rescaling parameter

true if rescaling is enabled

Definition at line 102 of file PolyMatchStringKernel.h.

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

initialize kernel

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

Reimplemented from CStringKernel< char >.

Definition at line 52 of file PolyMatchStringKernel.cpp.

void set_rescaling_enabled ( bool  n  ) 

enable rescaling by length of feature vector

n true to enable

Definition at line 93 of file PolyMatchStringKernel.h.

Member Data Documentation

int32_t degree [protected]


Definition at line 123 of file PolyMatchStringKernel.h.

bool inhomogene [protected]

if kernel is inhomogeneous

Definition at line 125 of file PolyMatchStringKernel.h.

bool rescaling [protected]

true to rescale kernel with string length

Definition at line 127 of file PolyMatchStringKernel.h.

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