I. Introduction
In the global black-box optimization literature, efforts have seldom been made to automate the reuse of knowledge acquired from past problem-solving experiences. This limitation is primarily due to the lack of problem-specific data available prior to the onset of the search, which makes it difficult to ascertain (offline) the relationships across problems. In contrast, the idea of taking advantage of available data from various source tasks to improve the learning of a related target task has achieved significant success in the field of machine learning—under the label of transfer learning [1]–[5]. With this in mind, and under the observation that optimization problems of practical interest seldom exist in isolation [6], our goal in this paper is to achieve an algorithmic realization of the novel concept of transfer optimization [7]. Our contributions are expected to benefit real-world optimization settings of a time-sensitive nature, where ignoring prior experience implies the waste of a rich pool of knowledge that can otherwise be exploited to facilitate efficient re-exploration of possibly overlapping search spaces.