The FixedDegree String kernel takes as input two strings of same size and counts the number of matches of length d.
![\[ k({\bf x}, {\bf x'}) = \sum_{i=0}^{l-d} I({\bf x}_{i,i+1,\dots,i+d-1} = {\bf x'}_{i,i+1,\dots,i+d-1}) \]](form_126.png)
Note that additional normalisation is applied, i.e.
![\[ k'({\bf x}, {\bf x'})=\frac{k({\bf x}, {\bf x'})}{\sqrt{k({\bf x}, {\bf x})k({\bf x'}, {\bf x'})}} \]](form_127.png)
Definition at line 31 of file FixedDegreeStringKernel.h.
Public Member Functions | |
| CFixedDegreeStringKernel () | |
| CFixedDegreeStringKernel (int32_t size, int32_t degree) | |
| CFixedDegreeStringKernel (CStringFeatures< char > *l, CStringFeatures< char > *r, int32_t degree) | |
| virtual | ~CFixedDegreeStringKernel () |
| virtual bool | init (CFeatures *l, CFeatures *r) |
| virtual void | cleanup () |
| virtual EKernelType | get_kernel_type () |
| virtual const char * | get_name () const |
Protected Member Functions | |
| float64_t | compute (int32_t idx_a, int32_t idx_b) |
Protected Attributes | |
| int32_t | degree |
default constructor
Definition at line 27 of file FixedDegreeStringKernel.cpp.
| CFixedDegreeStringKernel | ( | int32_t | size, | |
| int32_t | degree | |||
| ) |
constructor
| size | cache size | |
| degree | the degree |
Definition at line 33 of file FixedDegreeStringKernel.cpp.
| CFixedDegreeStringKernel | ( | CStringFeatures< char > * | l, | |
| CStringFeatures< char > * | r, | |||
| int32_t | degree | |||
| ) |
constructor
| l | features of left-hand side | |
| r | features of right-hand side | |
| degree | the degree |
Definition at line 39 of file FixedDegreeStringKernel.cpp.
| ~CFixedDegreeStringKernel | ( | ) | [virtual] |
Definition at line 47 of file FixedDegreeStringKernel.cpp.
| void cleanup | ( | ) | [virtual] |
clean up kernel
Reimplemented from CKernel.
Definition at line 58 of file FixedDegreeStringKernel.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 |
Implements CKernel.
Definition at line 63 of file FixedDegreeStringKernel.cpp.
| virtual EKernelType get_kernel_type | ( | ) | [virtual] |
return what type of kernel we are
Implements CStringKernel< char >.
Definition at line 73 of file FixedDegreeStringKernel.h.
| virtual const char* get_name | ( | ) | const [virtual] |
return the kernel's name
Reimplemented from CStringKernel< char >.
Definition at line 82 of file FixedDegreeStringKernel.h.
initialize kernel
| l | features of left-hand side | |
| r | features of right-hand side |
Reimplemented from CStringKernel< char >.
Definition at line 52 of file FixedDegreeStringKernel.cpp.
int32_t degree [protected] |
the degree
Definition at line 95 of file FixedDegreeStringKernel.h.
