PLearn::LiftBinaryCostFunction Class Reference

#include <LiftBinaryCostFunction.h>

Inheritance diagram for PLearn::LiftBinaryCostFunction:

[legend]Collaboration diagram for PLearn::LiftBinaryCostFunction:

[legend]List of all members.

Public Member Functions
	LiftBinaryCostFunction (bool make_pos_output=false)
	PLEARN_DECLARE_OBJECT (LiftBinaryCostFunction)
virtual string	info () const
	returns a bit more informative string about object (default returns classname())
virtual real	evaluate (const Vec &output, const Vec &target) const
	returns K(x1,x2)
Static Protected Member Functions
void	declareOptions (OptionList &ol)
	redefine this in subclasses: call declareOption(...) for each option, and then call inherited::declareOptions(options) ( see the declareOption function further down)
Protected Attributes
bool	make_positive_output
Private Types
typedef Kernel	inherited

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Detailed Description

This class allows us to compute the lift (used by Bell Canada) of a binary classification problem. Since we need the output AND the target to be represented by a single cost (the method evaluate returns only a real), we will use a trick. cost = output[class#1], if target = 1 = -output[class#1], if target = 0 or, if the make_positive_output flag is true: cost = sigmoid(output[class#1]), if target = 1 = -sigmoid(output[class#1]), if target = 0

Definition at line 63 of file LiftBinaryCostFunction.h.

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Member Typedef Documentation

typedef Kernel PLearn::LiftBinaryCostFunction::inherited [private]

Reimplemented from PLearn::Kernel. Definition at line 65 of file LiftBinaryCostFunction.h.

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Constructor & Destructor Documentation

PLearn::LiftBinaryCostFunction::LiftBinaryCostFunction (  bool  make_pos_output = false  )  [inline]

Definition at line 71 of file LiftBinaryCostFunction.h. References make_positive_output.

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Member Function Documentation

void PLearn::LiftBinaryCostFunction::declareOptions (  OptionList &  ol  )  [static, protected]

redefine this in subclasses: call declareOption(...) for each option, and then call inherited::declareOptions(options) ( see the declareOption function further down) ex: static void declareOptions(OptionList& ol) { declareOption(ol, "inputsize", &MyObject::inputsize_, OptionBase::buildoption, "the size of the input\n it must be provided"); declareOption(ol, "weights", &MyObject::weights, OptionBase::learntoption, "the learnt model weights"); inherited::declareOptions(ol); } Reimplemented from PLearn::Kernel. Definition at line 76 of file LiftBinaryCostFunction.cc. References PLearn::declareOption(), and PLearn::OptionList.

real PLearn::LiftBinaryCostFunction::evaluate (  const Vec &  output, const Vec &  target )  const [virtual]

returns K(x1,x2) Implements PLearn::Kernel. Definition at line 51 of file LiftBinaryCostFunction.cc. References PLearn::TVec< T >::length(), make_positive_output, PLERROR, PLearn::sigmoid(), and PLearn::Vec.

virtual string PLearn::LiftBinaryCostFunction::info (   )  const [inline, virtual]

returns a bit more informative string about object (default returns classname()) Reimplemented from PLearn::Object. Definition at line 76 of file LiftBinaryCostFunction.h.

PLearn::LiftBinaryCostFunction::PLEARN_DECLARE_OBJECT (  LiftBinaryCostFunction   )

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Member Data Documentation

bool PLearn::LiftBinaryCostFunction::make_positive_output [protected]

Definition at line 68 of file LiftBinaryCostFunction.h. Referenced by evaluate(), and LiftBinaryCostFunction().

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

• LiftBinaryCostFunction.h
• LiftBinaryCostFunction.cc

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