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 28 of file AUCKernel.h.

Inheritance diagram for CAUCKernel:
Inheritance graph
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List of all members.

Public Member Functions

 CAUCKernel (int32_t size, CKernel *subkernel)
virtual ~CAUCKernel ()
CLabelssetup_auc_maximization (CLabels *labels)
virtual bool init (CFeatures *l, CFeatures *r)
virtual bool load_init (FILE *src)
virtual bool save_init (FILE *dest)
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::CAUCKernel ( int32_t  size,
CKernel subkernel 
)

constructor

Parameters:
size cache size
subkernel the subkernel

Definition at line 18 of file AUCKernel.cpp.

CAUCKernel::~CAUCKernel (  )  [virtual]

destructor

Definition at line 24 of file AUCKernel.cpp.


Member Function Documentation

float64_t CAUCKernel::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 127 of file AUCKernel.cpp.

virtual EKernelType CAUCKernel::get_kernel_type (  )  [virtual]

return what type of kernel we are

Returns:
kernel type AUC

Implements CKernel.

Definition at line 75 of file AUCKernel.h.

virtual const char* CAUCKernel::get_name (  )  const [virtual]

return the kernel's name

Returns:
name AUC

Implements CSGObject.

Definition at line 81 of file AUCKernel.h.

bool CAUCKernel::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 110 of file AUCKernel.cpp.

bool CAUCKernel::load_init ( FILE *  src  )  [virtual]

load kernel init_data

Parameters:
src file to load from
Returns:
if loading was successful

Implements CKernel.

Definition at line 117 of file AUCKernel.cpp.

bool CAUCKernel::save_init ( FILE *  dest  )  [virtual]

save kernel init_data

Parameters:
dest file to save to
Returns:
if saving was successful

Implements CKernel.

Definition at line 122 of file AUCKernel.cpp.

CLabels * CAUCKernel::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 30 of file AUCKernel.cpp.


Member Data Documentation

the subkernel

Definition at line 96 of file AUCKernel.h.


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

SHOGUN Machine Learning Toolbox - Documentation