dnf_composer::element::SigmoidFunction Struct Reference

Logistic (exponential) sigmoid. More...

#include <activation_function.h>

Inheritance diagram for dnf_composer::element::SigmoidFunction:

Collaboration diagram for dnf_composer::element::SigmoidFunction:

Public Member Functions
void	apply (const std::vector< double > &input, std::vector< double > &out) const override
	Apply the activation function in-place into a pre-allocated out buffer. out must already be sized to input.size(). No heap allocation occurs.
std::unique_ptr< ActivationFunction >	clone () const override
double	getSteepness () const
double	getXShift () const
std::vector< double >	operator() (const std::vector< double > &input) override
	Apply the activation function to input and return the result.
bool	operator== (const SigmoidFunction &other) const
void	print () const override
	SigmoidFunction (const SigmoidFunction &)=default
	SigmoidFunction (double x_shift, double steepness)
	Construct a sigmoid with the given inflection point and slope.
std::string	toString () const override
	~SigmoidFunction () override=default
Public Member Functions inherited from dnf_composer::element::ActivationFunction
	ActivationFunction ()=default
	ActivationFunction (const ActivationFunction &)=default
ActivationFunction &	operator= (const ActivationFunction &)=delete
virtual	~ActivationFunction ()=default

Public Attributes
double	steepness
	Slope at the inflection point (cedar/cosivina: beta).
double	x_shift
	Inflection point of the sigmoid (cedar: theta; cosivina: x0).
Public Attributes inherited from dnf_composer::element::ActivationFunction
ActivationFunctionType	type
	Concrete function type.

Detailed Description

Logistic (exponential) sigmoid.

Formula:

Cross-framework equivalence (formula-identical):

Framework	Type / call
dnf-composer	SigmoidFunction(x_shift, steepness)
cedar	ExpSigmoid(beta=steepness, theta=x_shift)
cosivina	sigmoid(beta=steepness, x0=x_shift)

All three use the same formula. Only the parameter names differ.

Constructor & Destructor Documentation

SigmoidFunction() [1/2]

dnf_composer::element::SigmoidFunction::SigmoidFunction ( const SigmoidFunction &  )

default

SigmoidFunction() [2/2]

dnf_composer::element::SigmoidFunction::SigmoidFunction	(	double	x_shift,
		double	steepness
	)

Construct a sigmoid with the given inflection point and slope.

Parameters

x_shift	Activation value at the inflection (threshold).
steepness	Slope parameter (larger = steeper transition).

~SigmoidFunction()

dnf_composer::element::SigmoidFunction::~SigmoidFunction ( )

overridedefault

Member Function Documentation

apply()

void dnf_composer::element::SigmoidFunction::apply ( const std::vector< double > &  input, std::vector< double > &  out  ) const

overridevirtual

Apply the activation function in-place into a pre-allocated out buffer. out must already be sized to input.size(). No heap allocation occurs.

Implements dnf_composer::element::ActivationFunction.

clone()

std::unique_ptr< ActivationFunction > dnf_composer::element::SigmoidFunction::clone ( ) const

overridevirtual

Implements dnf_composer::element::ActivationFunction.

getSteepness()

double dnf_composer::element::SigmoidFunction::getSteepness

(

)

const

getXShift()

double dnf_composer::element::SigmoidFunction::getXShift

(

)

const

operator()()

std::vector< double > dnf_composer::element::SigmoidFunction::operator() ( const std::vector< double > &  input )

overridevirtual

Apply the activation function to input and return the result.

Implements dnf_composer::element::ActivationFunction.

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operator==()

bool dnf_composer::element::SigmoidFunction::operator==

(

const SigmoidFunction &

other

)

const

print()

void dnf_composer::element::SigmoidFunction::print ( ) const

overridevirtual

Implements dnf_composer::element::ActivationFunction.

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toString()

std::string dnf_composer::element::SigmoidFunction::toString ( ) const

overridevirtual

Implements dnf_composer::element::ActivationFunction.

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Member Data Documentation

steepness

double dnf_composer::element::SigmoidFunction::steepness

Slope at the inflection point (cedar/cosivina: beta).

x_shift

double dnf_composer::element::SigmoidFunction::x_shift

Inflection point of the sigmoid (cedar: theta; cosivina: x0).

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

• include/elements/activation_function.h
• src/elements/activation_function.cpp