PLearn::LogAddVariable Class Reference

output = log(exp(input1)+exp(input2)) but it is computed in such a way as to preserve precision More...

#include <LogAddVariable.h>

Inheritance diagram for PLearn::LogAddVariable:

[legend]Collaboration diagram for PLearn::LogAddVariable:

[legend]List of all members.

Public Member Functions
	LogAddVariable ()
	Default constructor for persistence.
	LogAddVariable (Variable *input1, Variable *input2)
	PLEARN_DECLARE_OBJECT (LogAddVariable)
virtual void	build ()
	Should call simply inherited::build(), then this class's build_().
virtual void	recomputeSize (int &l, int &w) const
	Recomputes the length l and width w that this variable should have, according to its parent variables.
virtual void	fprop ()
	compute output given input
virtual void	bprop ()
virtual void	symbolicBprop ()
	compute a piece of new Var graph that represents the symbolic derivative of this Var
Protected Member Functions
void	build_ ()
Private Types
typedef BinaryVariable	inherited

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Detailed Description

output = log(exp(input1)+exp(input2)) but it is computed in such a way as to preserve precision

Definition at line 53 of file LogAddVariable.h.

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Member Typedef Documentation

typedef BinaryVariable PLearn::LogAddVariable::inherited [private]

Reimplemented from PLearn::BinaryVariable. Definition at line 55 of file LogAddVariable.h. Referenced by LogAddVariable().

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Constructor & Destructor Documentation

PLearn::LogAddVariable::LogAddVariable (   )  [inline]

Default constructor for persistence. Definition at line 59 of file LogAddVariable.h.

PLearn::LogAddVariable::LogAddVariable (  Variable *  input1, Variable *  input2 )

Definition at line 61 of file LogAddVariable.cc. References build_(), and inherited.

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Member Function Documentation

void PLearn::LogAddVariable::bprop (   )  [virtual]

Implements PLearn::Variable. Definition at line 98 of file LogAddVariable.cc. References PLearn::apply(), PLearn::Variable::nelems(), and PLearn::safeexp().

void PLearn::LogAddVariable::build (   )  [virtual]

Should call simply inherited::build(), then this class's build_(). This method should be callable again at later times, after modifying some option fields to change the "architecture" of the object. Reimplemented from PLearn::Variable. Definition at line 68 of file LogAddVariable.cc. References build_().

void PLearn::LogAddVariable::build_ (   )  [protected]

This method should be redefined in subclasses and do the actual building of the object according to previously set option fields. Constructors can just set option fields, and then call build_. This method is NOT virtual, and will typically be called only from three places: a constructor, the public virtual build() method, and possibly the public virtual read method (which calls its parent's read). build_() can assume that it's parent's build_ has already been called. Reimplemented from PLearn::Variable. Definition at line 75 of file LogAddVariable.cc. References PLearn::Var::length(), PLERROR, and PLearn::Var::width(). Referenced by build(), and LogAddVariable().

void PLearn::LogAddVariable::fprop (   )  [virtual]

compute output given input Implements PLearn::Variable. Definition at line 92 of file LogAddVariable.cc. References PLearn::apply(), and PLearn::logadd().

PLearn::LogAddVariable::PLEARN_DECLARE_OBJECT (  LogAddVariable   )

void PLearn::LogAddVariable::recomputeSize (  int &  l, int &  w )  const [virtual]

Recomputes the length l and width w that this variable should have, according to its parent variables. This is used for ex. by sizeprop() The default version stupidly returns the current dimensions, so make sure to overload it in subclasses if this is not appropriate. Reimplemented from PLearn::Variable. Definition at line 83 of file LogAddVariable.cc. References PLearn::Var::length(), and PLearn::Var::width().

void PLearn::LogAddVariable::symbolicBprop (   )  [virtual]

compute a piece of new Var graph that represents the symbolic derivative of this Var Reimplemented from PLearn::Variable. Definition at line 111 of file LogAddVariable.cc. References PLearn::exp().

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

• LogAddVariable.h
• LogAddVariable.cc

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