  Automated algorithm selection promises to support the user in the decisive
task of selecting a most suitable algorithm for a given problem. A common
component of these machine-trained techniques are regression models which
predict the performance of a given algorithm on a previously unseen problem
instance. In the context of numerical black-box optimization, such regression
models typically build on exploratory landscape analysis (ELA), which
quantifies several characteristics of the problem. These measures can be used
to train a supervised performance regression model.
  First steps towards ELA-based performance regression have been made in the
context of a fixed-target setting. In many applications, however, the user
needs to select an algorithm that performs best within a given budget of
function evaluations. Adopting this fixed-budget setting, we demonstrate that
it is possible to achieve high-quality performance predictions with
off-the-shelf supervised learning approaches, by suitably combining two
differently trained regression models. We test this approach on a very
challenging problem: algorithm selection on a portfolio of very similar
algorithms, which we choose from the family of modular CMA-ES algorithms.
