Package transsys :: Module optim :: Class ExponentialFunction
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Class ExponentialFunction

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            object --+    
                     |    
TransformationFunction --+
                         |
                        ExponentialFunction

Exponential parameter transformation.

This is a callable class implementing the transformation function y = minValue + coefficient * exp(exponentMultiplier * x).

Instance Methods [hide private]
 
__init__(self, exponentMultiplier=1.0, coefficient=1.0, minValue=0.0)
Constructor.
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__call__(self, x)
Compute function value.
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__str__(self)
str(x)
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parse_variables(self, f) source code
 
clip(self, y)
Clip y to the nearest admissible value.
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float or None
inverse(self, y)
Compute inverse.
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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 = 'ExponentialFunction'
Properties [hide private]

Inherited from object: __class__

Method Details [hide private]

__init__(self, exponentMultiplier=1.0, coefficient=1.0, minValue=0.0)
(Constructor)

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Constructor.

Overrides: object.__init__

__call__(self, x)
(Call operator)

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Compute function value.

Overrides: TransformationFunction.__call__

__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 inverse.

Notice that the inverse diverges as y approaches minValue. Exactly at minValue, the inverse method attempts to return the smallest value that can be transformed without a floating point overflow.

Returns: float or None
inverse function value, or None if y is out of admissible range
Overrides: TransformationFunction.inverse