The AUC kernel can be used to maximize the area under the receiver operator characteristic curve (AUC) instead of margin in SVM training.
It takes as argument a sub-kernel and Labels based on which number of positive labels times number of negative labels many ``virtual'' examples are created that ensure that all positive examples get a higher score than all negative examples in training.
Definition at line 33 of file AUCKernel.h.
Public Member Functions | |
CAUCKernel (int32_t size, CKernel *subkernel) | |
virtual | ~CAUCKernel () |
CLabels * | setup_auc_maximization (CLabels *labels) |
virtual bool | init (CFeatures *l, CFeatures *r) |
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 | |
CKernel * | subkernel |
CAUCKernel | ( | int32_t | size, | |
CKernel * | subkernel | |||
) |
constructor
size | cache size | |
subkernel | the subkernel |
Definition at line 20 of file AUCKernel.cpp.
~CAUCKernel | ( | ) | [virtual] |
destructor
Definition at line 26 of file AUCKernel.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 119 of file AUCKernel.cpp.
virtual EKernelType get_kernel_type | ( | ) | [virtual] |
return what type of kernel we are
Implements CKernel.
Definition at line 66 of file AUCKernel.h.
virtual const char* get_name | ( | ) | const [virtual] |
return the kernel's name
Implements CSGObject.
Definition at line 72 of file AUCKernel.h.
initialize kernel
l | features of left-hand side | |
r | features of right-hand side |
Reimplemented from CSimpleKernel< uint16_t >.
Definition at line 112 of file AUCKernel.cpp.
initialize kernel based on current labeling and subkernel
labels | - current labeling |
Definition at line 32 of file AUCKernel.cpp.
the subkernel
Definition at line 87 of file AUCKernel.h.