Tournament selection and Minimizing objective

[David Valera Laborda]

Here it comes my doubt. Im looking for minimizing my singled-objetive. When I come up for searching in the library code of DEAP of how the selection via tournament is done in reality.

def selTournament(individuals, k, tournsize, fit_attr="fitness"):

chosen = []
for i in range(k):
aspirants = selRandom(individuals, tournsize)
chosen.append(max(aspirants, key=attrgetter(fit_attr)))
return chosen

The chosen is elected by the maximum fitness, being this just the opposite of what we want. 

I need somebody to give me a check of this thing that I come up with.

[François-Michel De Rainville]

It is done on the weighted objectives. For minimization the weight should be negative.

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[David Valera Laborda]

Well yeah, but how can I verify that? I mean, in terms of code, the EAsimplealgorithm call the selection method which the code is the one above. And in that code it is always selected the maximum.

[François-Michel De Rainville]

You can check how "less than" in overridden in the fitness class. Maximum, and sorting in general, uses these methods from the object.

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[David Valera Laborda]

Wells I was expecting some Code to learn how It is done. But thanks anyway. At least now i know it is correct

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[François-Michel De Rainville]

https://github.com/DEAP/deap/blob/ed7f04d330880839c11e4e624566c9fa616181bb/deap/base.py#L243

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