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Add arbitrary size function keyword arg to selDoubleTournament #306

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Add arbitrary size function keyword arg to selDoubleTournament #306

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12 changes: 8 additions & 4 deletions deap/tools/selection.py
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Original file line number Diff line number Diff line change
Expand Up @@ -102,7 +102,7 @@ def selRoulette(individuals, k, fit_attr="fitness"):
return chosen


def selDoubleTournament(individuals, k, fitness_size, parsimony_size, fitness_first, fit_attr="fitness"):
def selDoubleTournament(individuals, k, fitness_size, parsimony_size, fitness_first, fit_attr="fitness", size=len):
"""Tournament selection which use the size of the individuals in order
to discriminate good solutions. This kind of tournament is obviously
useless with fixed-length representation, but has been shown to
Expand Down Expand Up @@ -138,6 +138,7 @@ def selDoubleTournament(individuals, k, fitness_size, parsimony_size, fitness_fi
shown that this parameter does not have a significant effect in most cases\
(see [Luke2002fighting]_).
:param fit_attr: The attribute of individuals to use as selection criterion
:param size: Function taking an individual as argument and returning a positive real number. Default len.
:returns: A list of selected individuals.

.. [Luke2002fighting] Luke and Panait, 2002, Fighting bloat with
Expand All @@ -153,9 +154,13 @@ def _sizeTournament(individuals, k, select):
prob = parsimony_size / 2.
ind1, ind2 = select(individuals, k=2)

if len(ind1) > len(ind2):
# Compute sizes.
size1 = size(ind1)
size2 = size(ind2)

if size1 > size2:
ind1, ind2 = ind2, ind1
elif len(ind1) == len(ind2):
elif size1 == size2:
# random selection in case of a tie
prob = 0.5

Expand Down Expand Up @@ -323,4 +328,3 @@ def selAutomaticEpsilonLexicase(individuals, k):
__all__ = ['selRandom', 'selBest', 'selWorst', 'selRoulette',
'selTournament', 'selDoubleTournament', 'selStochasticUniversalSampling',
'selLexicase', 'selEpsilonLexicase', 'selAutomaticEpsilonLexicase']