Package transsys :: Module optim :: Class ArctanFunction
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Class ArctanFunction

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            object --+    
                     |    
TransformationFunction --+
                         |
                        ArctanFunction

Arcus tangens transformation function.

The arctan approaches its minimum and its maximum with O(1/x). From a perspective of numeric computation, this makes it favourable over the exponential sigmoid function, as x can take on values from the greatest possible range without incurring floating point limitations.

Instance Methods [hide private]
 
__init__(self, minValue=0.0, maxValue=1.0)
x.__init__(...) initializes x; see x.__class__.__doc__ for signature
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__call__(self, x)
Compute the transformed value of x.
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__str__(self)
str(x)
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parse_variables(self, f) source code
 
getMaxValue(self) source code
 
clip(self, y)
Clip y to the nearest admissible value.
source code
 
inverse(self, y)
Compute the inverse value of y.
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Inherited from TransformationFunction: check_savefile_magic, parse

Inherited from object: __delattr__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __repr__, __setattr__

Class Variables [hide private]
  functionName = 'ArctanFunction'
Properties [hide private]

Inherited from object: __class__

Method Details [hide private]

__init__(self, minValue=0.0, maxValue=1.0)
(Constructor)

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x.__init__(...) initializes x; see x.__class__.__doc__ for signature

Overrides: object.__init__
(inherited documentation)

__call__(self, x)
(Call operator)

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Compute the transformed value of x.

Overrides: TransformationFunction.__call__
(inherited documentation)

__str__(self)
(Informal representation operator)

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str(x)

Overrides: object.__str__
(inherited documentation)

parse_variables(self, f)

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Overrides: TransformationFunction.parse_variables

clip(self, y)

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Clip y to the nearest admissible value.

Overrides: TransformationFunction.clip
(inherited documentation)

inverse(self, y)

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Compute the inverse value of y.

This method should return the untransformed value x corresponding to y, such that f(x) = y.

Overrides: TransformationFunction.inverse
(inherited documentation)