Re: [cilib-devel] Mutation and additional parameters in Individuals

[Andries E. <en...@cs...>]

Maybe we should discuss this at the next CIlib meeting?

Gary Pampara wrote:
> Hmmm.
>
> This does make the implementation rather complex. One the one hand, having the 
> entity know about its strategy parameters (if any) could be a good thing, 
> however, the problem does come in where the strategy parameters are shared 
> amoungst entities.
>
> I'm not really sure that this will be a simple addition.
>
> Regards,
> Gary
>
> On Monday 13 July 2009 13:37:10 Andries Engelbrecht wrote:
>   
>> Hi,
>>
>>     
>>> 1. Where should the definition of the initialization for these extra
>>> parameters be placed? On the individual? In the EC algorithm? Within the
>>> IterationStrategy?
>>>       
>> You refer to the Strategy parameters here. What we have to remember
>> is that strategy parameters can be "global" or "local". What I mean by
>> this is that the same parameter can be used for all individuals, or each
>> individual can have its own parameter. The latter can have an even
>> smaller granularity in that each dimension of each individual can have
>> its own strategy parameter. We should also think about cultural
>> algorithms where there is a bielief space, which have some relation
>> to strategy parameters. The solution should take the latter into account.
>>
>> We may argue that not all EAs have strategy parameters, e.g. GA.
>> However, in our implementation, parameters such as crossover and
>> mutation probability can be seen as strategy parameters with no
>> adaptation.
>>
>> So the question is where does strategy parameters belong? My
>> feeling is that these should belong to Algorithms. Not just EC
>> algorithms, but all algorithms. Remember that PSO and others
>> also have "strategy parameters". performIteration will then have
>> a call to some strategy to "adapt" the parameters. And this
>> basically should replace ControlParameters.
>>
>>     
>>> 2. How should mutation be handled? Should the strategies know to inspect
>>> the individual for strategy parameters? Should the mutation rather be
>>> done in a separate class?
>>>       
>> Remember that mutation can be applied in PSO and others. Mutation
>> is a separate process, that may, or may not make use of the
>> strategy parameters. So, mutation should be a separate class.
>>
>> This then also tells me that the strategy parameters should be on
>> a higher level than on entity level.
>>
>>     
>>> Regards,
>>> Gary
>>>
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-- 
==========================================================
Prof Andries P Engelbrecht
South African Research Chair in Artificial Intelligence

Fundamentals of Computational Swarm Intelligence,
John Wiley & Sons, December 2005.

Computational Intelligence, An Introduction
John Wiley & Sons, Second edition to be published soon

Computational Intelligence Research Group:
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