edu.memphis.ccrg.lida.framework.strategies
Class SigmoidDecayStrategy

java.lang.Object
  edu.memphis.ccrg.lida.framework.initialization.InitializableImpl
      edu.memphis.ccrg.lida.framework.strategies.StrategyImpl
          edu.memphis.ccrg.lida.framework.strategies.SigmoidDecayStrategy

All Implemented Interfaces:

Initializable, DecayStrategy, Strategy

public class SigmoidDecayStrategy
extends StrategyImpl
implements DecayStrategy

Default implementation of sigmoid decay. Uses two parameters in activation calculation. Can pass these parameters when the strategy is initialized. (see factoriesData.xml). Alternatively, parameters can be passed in the decay method call. Formula used: 1 / (1 + exp(-a* x + c))

Author:

Javier Snaider, Ryan J. McCall

Constructor Summary

SigmoidDecayStrategy()

Method Summary

double	decay(double currentActivation, long ticks, java.util.Map<java.lang.String,? extends java.lang.Object> params) Decays the current activation according to some internal decay function.
double	decay(double currentActivation, long ticks, java.lang.Object... params) Decays the current activation according to some internal decay function.
void	init() If this method is overridden, this init() must be called first! i.e.

Methods inherited from class edu.memphis.ccrg.lida.framework.initialization.InitializableImpl

containsParameter, getParam, getParameters, init

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface edu.memphis.ccrg.lida.framework.initialization.Initializable

containsParameter, getParam, getParameters, init

Constructor Detail

SigmoidDecayStrategy

public SigmoidDecayStrategy()

Method Detail

init

public void init()

If this method is overridden, this init() must be called first! i.e. super.init(); Will set parameters with the following names:

a slope component of the decay function's linear scaling, 1 / (1 + exp(-a* x + c))
c intercept component of the decay function's linear scaling, 1 / (1 + exp(-a* x + c))
If any parameter is not specified its default value will be used.

Specified by:

init in interface Initializable

Overrides:

init in class InitializableImpl

See Also:

Initializable

decay

public double decay(double currentActivation,
                    long ticks,
                    java.lang.Object... params)

Decays the current activation according to some internal decay function.

Specified by:

decay in interface DecayStrategy

Parameters:

currentActivation - activation of the entity before decay.

ticks - The number of ticks to decay.

params - optionally accepts 2 double parameters of sigmoid activation calculation.

Returns:

new activation

decay

public double decay(double currentActivation,
                    long ticks,
                    java.util.Map<java.lang.String,? extends java.lang.Object> params)

Decays the current activation according to some internal decay function.

Specified by:

decay in interface DecayStrategy

Parameters:

currentActivation - activation of the entity before decay.

ticks - how much time has passed since last decay

params - optionally accepts 2 parameters of sigmoid activation calculation.

Returns:

new activation amount