Package topo :: Package numbergen :: Module basic :: Class ExponentialDecay

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Class ExponentialDecay

source code

Function object that provides a value that decays according to an exponential function, based on topo.sim.time().

Returns starting_value*base^(-time/time_constant).

See http://en.wikipedia.org/wiki/Exponential_decay.

Nested Classes

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Inherited from param.parameterized.Parameterized: __metaclass__

Instance Methods

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__call__(self)

source code

Inherited from NumberGenerator: __abs__, __add__, __div__, __floordiv__, __mod__, __mul__, __neg__, __pos__, __pow__, __radd__, __rdiv__, __rfloordiv__, __rmod__, __rmul__, __rpow__, __rsub__, __rtruediv__, __sub__, __truediv__

Inherited from param.parameterized.Parameterized: __getstate__, __init__, __repr__, __setstate__, __str__, debug, defaults, force_new_dynamic_value, get_param_values, get_value_generator, inspect_value, message, print_param_values, script_repr, set_default, set_dynamic_time_fn, set_param, state_pop, state_push, verbose, warning

Inherited from param.parameterized.Parameterized (private): _add_parameter, _instantiate_param, _set_name, _setup_params

Inherited from object: __delattr__, __format__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __setattr__, __sizeof__, __subclasshook__

Class Methods

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Inherited from param.parameterized.Parameterized: params, print_param_defaults

Class Variables

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starting_value = param.Number(1.0, doc= "Value used for time z...
Value used for time zero.

ending_value = param.Number(0.0, doc= "Value used for time inf...
Value used for time infinity.

time_constant = param.Number(10000, doc= ...
Time scale for the exponential; large values give slow decay.

base = param.Number(e, doc= ...
Base of the exponent; the default yields starting_value*exp(-t/time_constant).

time_fn = param.Callable(default= topo.sim.time, doc= ...
Function to generate the time used for the decay.

name = <param.parameterized.String object at 0xb1ff9ac>
String identifier for this object.

Inherited from param.parameterized.Parameterized: print_level

Properties

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Inherited from object: __class__

Method Details

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call(self)
(Call operator)

source code

Overrides: NumberGenerator.__call__

Class Variable Details

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starting_value

Value used for time zero.

Value:

param.Number(1.0, doc= "Value used for time zero.")

ending_value

Value used for time infinity.

Value:

param.Number(0.0, doc= "Value used for time infinity.")

time_constant

Time scale for the exponential; large values give slow decay.

Value:

param.Number(10000, doc= """
        Time scale for the exponential; large values give slow decay.""")

base

Base of the exponent; the default yields starting_value*exp(-t/time_constant). Another popular choice of base is 2, which allows the time_constant to be interpreted as a half-life.

Value:

param.Number(e, doc= """
        Base of the exponent; the default yields starting_value*exp(-t/time_consta
nt).
        Another popular choice of base is 2, which allows the
        time_constant to be interpreted as a half-life.""")

time_fn

Function to generate the time used for the decay.

Value:

param.Callable(default= topo.sim.time, doc= """
        Function to generate the time used for the decay.""")

Class ExponentialDecay

__call__(self) (Call operator)

starting_value

ending_value

time_constant

base

time_fn

call(self)
(Call operator)