3 research outputs found
Optimisation via encodings: a renormalisation group perspective
The traditional way of tackling discrete optimization problems is by using
local search on suitably defined cost or fitness landscapes. Such approaches
are however limited by the slowing down that occurs when local minima, that are
a feature of the typically rugged landscapes encountered, arrest the progress
of the search process. Another way of tackling optimization problems is by the
use of heuristic approximations to estimate a global cost minimum. Here we
present a combination of these two approaches by using cover-encoding maps
which map processes from a larger search space to subsets of the original
search space. The key idea is to construct cover-encoding maps with the help of
suitable heuristics that single out near-optimal solutions and result in
landscapes on the larger search space that no longer exhibit trapping local
minima. The processes that are typically employed involve some form of
coarse-graining, and we suggest here that they can be viewed as avatars of
renormalisation group transformations.Comment: 17 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1806.0524
SYSTEMATIC APPROXIMATIONS FOR GENETIC DYNAMICS
Although much progress has been made in recent years in describing the dynamics of genetic systems, both in population genetics and evolutionary computation, there is still a conspicuous lack of tools with which to derive systematic, approximate solutions to their dynamics. In this article, we propose and study perturbation theory and the renormalization group as potential tools to fill this gap. We concentrate mainly on selection–mutation systems, showing different implementations of the perturbative framework, developing, for example, perturbative expansions for the eigenvalues and eigenvectors of the transition matrix. The main focus, however, is on diagrammatic methods, taken from physics, where we show how approximations can be built up using a pictorial representation generated by a simple set of rules, and how the renormalization group can be used to systematically improve the perturbation theory.Genetic dynamics, mutation, selection, perturbation theory, renormalization group