mlpack::ann::SoftsignFunction Class Reference

The softsign function, defined by. More...

#include <softsign_function.hpp>

Static Public Member Functions
static double	Fn (const double x)
	Computes the softsign function. More...
template<typename InputVecType , typename OutputVecType >
static void	Fn (const InputVecType &x, OutputVecType &y)
	Computes the softsign function. More...
static double	Deriv (const double y)
	Computes the first derivative of the softsign function. More...
template<typename InputVecType , typename OutputVecType >
static void	Deriv (const InputVecType &y, OutputVecType &x)
	Computes the first derivatives of the softsign function. More...
static double	Inv (const double y)
	Computes the inverse of the softsign function. More...
template<typename InputVecType , typename OutputVecType >
static void	Inv (const InputVecType &y, OutputVecType &x)
	Computes the inverse of the softsign function. More...

Detailed Description

The softsign function, defined by.

\begin{eqnarray*} f(x) &=& \frac{x}{1 + |x|} \\ f'(x) &=& (1 - |f(x)|)^2 \\ f(x) &=& \left\{ \begin{array}{lr} -\frac{x}{1 - x} & : x \le 0 \\ \frac{x}{1 + x} & : x > 0 \end{array} \right. \end{eqnarray*}

Member Function Documentation

Deriv() [1/2]

static double mlpack::ann::SoftsignFunction::Deriv ( const double  y )

inlinestatic

Computes the first derivative of the softsign function.

Parameters

y	Input activation.

Returns

f'(x)

Deriv() [2/2]

template<typename InputVecType , typename OutputVecType >

static void mlpack::ann::SoftsignFunction::Deriv ( const InputVecType &  y, OutputVecType &  x  )

inlinestatic

Computes the first derivatives of the softsign function.

Parameters

y	Input activations.
x	The resulting derivatives.

Fn() [1/2]

static double mlpack::ann::SoftsignFunction::Fn ( const double  x )

inlinestatic

Computes the softsign function.

Parameters

x	Input data.

Returns

f(x).

Fn() [2/2]

template<typename InputVecType , typename OutputVecType >

static void mlpack::ann::SoftsignFunction::Fn ( const InputVecType &  x, OutputVecType &  y  )

inlinestatic

Computes the softsign function.

Parameters

x	Input data.
y	The resulting output activation.

Inv() [1/2]

static double mlpack::ann::SoftsignFunction::Inv ( const double  y )

inlinestatic

Computes the inverse of the softsign function.

Parameters

y	Input data.

Returns

f^{-1}(y)

Inv() [2/2]

template<typename InputVecType , typename OutputVecType >

static void mlpack::ann::SoftsignFunction::Inv ( const InputVecType &  y, OutputVecType &  x  )

inlinestatic

Computes the inverse of the softsign function.

Parameters

y	Input data.
x	The resulting inverse of the input data.

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

• src/mlpack/methods/ann/activation_functions/softsign_function.hpp