The logistic function, defined by. More...

Static Public Member Functions
static double	deriv (const double y)
	Computes the first derivative of the logistic function. More...

template<typename InputVecType , typename OutputVecType >
static void	deriv (const InputVecType &y, OutputVecType &x)
	Computes the first derivatives of the logistic function. More...

template<typename eT >
static double	fn (const eT x)
	Computes the logistic function. More...

template<typename InputVecType , typename OutputVecType >
static void	fn (const InputVecType &x, OutputVecType &y)
	Computes the logistic function. More...

static double	inv (const double y)
	Computes the inverse of the logistic function. More...

template<typename InputVecType , typename OutputVecType >
static void	inv (const InputVecType &y, OutputVecType &x)
	Computes the inverse of the logistic function. More...

Detailed Description

The logistic function, defined by.

$\begin{eqnarray*} f(x) &=& \frac{1}{1 + e^{-x}} \\ f'(x) &=& f(x) * (1 - f(x)) \\ f^{-1}(y) &=& ln(\frac{y}{1-y}) \end{eqnarray*}$

Definition at line 29 of file logistic_function.hpp.

Member Function Documentation

static double mlpack::ann::LogisticFunction::deriv ( const double y )

inlinestatic

Computes the first derivative of the logistic function.

Parameters

x	Input data.

Returns: f'(x)

Definition at line 70 of file logistic_function.hpp.

template<typename InputVecType , typename OutputVecType >

static void mlpack::ann::LogisticFunction::deriv	(	const InputVecType &	y,
		OutputVecType &	x
	)

inlinestatic

Computes the first derivatives of the logistic function.

Parameters

y	Input activations.
x	The resulting derivatives.

Definition at line 82 of file logistic_function.hpp.

template<typename eT >

static double mlpack::ann::LogisticFunction::fn ( const eT x )

inlinestatic

Computes the logistic function.

Parameters

x	Input data.

Returns: f(x).

Definition at line 39 of file logistic_function.hpp.

template<typename InputVecType , typename OutputVecType >

static void mlpack::ann::LogisticFunction::fn	(	const InputVecType &	x,
		OutputVecType &	y
	)

inlinestatic

Computes the logistic function.

Parameters

x	Input data.
y	The resulting output activation.

Definition at line 59 of file logistic_function.hpp.

static double mlpack::ann::LogisticFunction::inv ( const double y )

inlinestatic

Computes the inverse of the logistic function.

Parameters

y	Input data.

Returns: f^{-1}(y)

Definition at line 93 of file logistic_function.hpp.

template<typename InputVecType , typename OutputVecType >

static void mlpack::ann::LogisticFunction::inv	(	const InputVecType &	y,
		OutputVecType &	x
	)

inlinestatic

Computes the inverse of the logistic function.

Parameters

y	Input data.

Returns: x The resulting inverse of the input data.

Definition at line 105 of file logistic_function.hpp.

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

src/mlpack/methods/ann/activation_functions/logistic_function.hpp

Static Public Member Functions

Detailed Description

Member Function Documentation