CAUCKernel Class Reference

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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:

List of all members.

Public Member Functions
	CAUCKernel (void)
	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
virtual EFeatureClass	get_feature_class ()
virtual EFeatureType	get_feature_type ()
Protected Member Functions
virtual float64_t	compute (int32_t idx_a, int32_t idx_b)
Protected Attributes
CKernel *	subkernel

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Constructor & Destructor Documentation

CAUCKernel

(

void

)

default constructor

Definition at line 27 of file AUCKernel.cpp.

CAUCKernel	(	int32_t	size,
		CKernel *	subkernel
	)

constructor

Parameters:

	size	cache size
	subkernel	the subkernel

Definition at line 33 of file AUCKernel.cpp.

~CAUCKernel

(

)

[virtual]

destructor

Definition at line 40 of file AUCKernel.cpp.

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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

Reimplemented from CDotKernel.

Definition at line 132 of file AUCKernel.cpp.

virtual EFeatureClass get_feature_class

(

)

[virtual]

return feature class the kernel can deal with

Returns:

feature class SIMPLE

Reimplemented from CDotKernel.

Definition at line 83 of file AUCKernel.h.

virtual EFeatureType get_feature_type

(

)

[virtual]

return feature type the kernel can deal with

Returns:

word feature type

Reimplemented from CDotKernel.

Definition at line 89 of file AUCKernel.h.

virtual EKernelType get_kernel_type

(

)

[virtual]

return what type of kernel we are

Returns:

kernel type AUC

Implements CDotKernel.

Definition at line 71 of file AUCKernel.h.

virtual const char* get_name

(

void

)

const [virtual]

return the kernel's name

Returns:

name AUC

Reimplemented from CDotKernel.

Definition at line 77 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 CDotKernel.

Definition at line 125 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 46 of file AUCKernel.cpp.

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Member Data Documentation

CKernel* subkernel [protected]

the subkernel

Definition at line 104 of file AUCKernel.h.

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

• AUCKernel.h
• AUCKernel.cpp