Public Member Functions | Protected Member Functions | Protected Attributes

CAUCKernel Class Reference


Detailed Description

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.

Inheritance diagram for CAUCKernel:
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Public Member Functions

 CAUCKernel (int32_t size, CKernel *subkernel)
virtual ~CAUCKernel ()
CLabelssetup_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

CKernelsubkernel

Constructor & Destructor Documentation

CAUCKernel ( int32_t  size,
CKernel subkernel 
)

constructor

Parameters:
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.


Member Function Documentation

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 119 of file AUCKernel.cpp.

virtual EKernelType get_kernel_type (  )  [virtual]

return what type of kernel we are

Returns:
kernel type AUC

Implements CKernel.

Definition at line 66 of file AUCKernel.h.

virtual const char* get_name (  )  const [virtual]

return the kernel's name

Returns:
name AUC

Implements CSGObject.

Definition at line 72 of file AUCKernel.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 CSimpleKernel< uint16_t >.

Definition at line 112 of file AUCKernel.cpp.

CLabels * setup_auc_maximization ( CLabels labels  ) 

initialize kernel based on current labeling and subkernel

Parameters:
labels - current labeling
Returns:
new label object to be used together with this kernel in SVM training for AUC maximization

Definition at line 32 of file AUCKernel.cpp.


Member Data Documentation

CKernel* subkernel [protected]

the subkernel

Definition at line 87 of file AUCKernel.h.


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SHOGUN Machine Learning Toolbox - Documentation