3 research outputs found
Bounding Bloat in Genetic Programming
While many optimization problems work with a fixed number of decision
variables and thus a fixed-length representation of possible solutions, genetic
programming (GP) works on variable-length representations. A naturally
occurring problem is that of bloat (unnecessary growth of solutions) slowing
down optimization. Theoretical analyses could so far not bound bloat and
required explicit assumptions on the magnitude of bloat. In this paper we
analyze bloat in mutation-based genetic programming for the two test functions
ORDER and MAJORITY. We overcome previous assumptions on the magnitude of bloat
and give matching or close-to-matching upper and lower bounds for the expected
optimization time. In particular, we show that the (1+1) GP takes (i)
iterations with bloat control on ORDER as well as
MAJORITY; and (ii) and
(and for )
iterations without bloat control on MAJORITY.Comment: An extended abstract has been published at GECCO 201
Destructiveness of Lexicographic Parsimony Pressure and Alleviation by a Concatenation Crossover in Genetic Programming
For theoretical analyses there are two specifics distinguishing GP from many
other areas of evolutionary computation. First, the variable size
representations, in particular yielding a possible bloat (i.e. the growth of
individuals with redundant parts). Second, the role and realization of
crossover, which is particularly central in GP due to the tree-based
representation. Whereas some theoretical work on GP has studied the effects of
bloat, crossover had a surprisingly little share in this work. We analyze a
simple crossover operator in combination with local search, where a preference
for small solutions minimizes bloat (lexicographic parsimony pressure); the
resulting algorithm is denoted Concatenation Crossover GP. For this purpose
three variants of the well-studied MAJORITY test function with large plateaus
are considered. We show that the Concatenation Crossover GP can efficiently
optimize these test functions, while local search cannot be efficient for all
three variants independent of employing bloat control.Comment: to appear in PPSN 201
A comparison between Geometric Semantic GP and Cartesian GP for Boolean functions learning?
2siGeometric Semantic Genetic Programming (GSGP) is a recently defined form of Genetic Programming (GP) that has shown promising results on single output Boolean problems when compared with standard tree-based GP. In this paper we compare GSGP with Cartesian GP (CGP) on comprehensive set of Boolean benchmarks, consisting of both single and multiple outputs Boolean problems. The results obtained show that GSGP outperforms also CGP, confirming the efficacy of GSGP in solving Boolean problems.nonenoneMambrini Andrea; Manzoni LucaMambrini, Andrea; Manzoni, Luc