The main focus of this paper is on the family of evolutionary algorithms and their real-life applications. We present the following algorithms: genetic algorithms, genetic programming, differential evolution, evolution strategies, and evolutionary programming. Each technique is presented in the pseudo-code form, which can be used for its easy implementation in any programming language. We present the main properties of each algorithm described in this paper. We also show many state-of-the-art practical applications and modifications of the early evolutionary methods. The open research issues are indicated for the family of evolutionary algorithms.

In this paper, we present the Swarm Intelligence (SI) concept and mention some metaheuristics belonging to the SI. We present the Particle Swarm Optimization (PSO) algorithm and the Ant Colony Optimization (ACO) method as the representatives of the SI approach. In recent years, researchers are eager to develop and apply a variety of these two methods, despite the development of many other newer methods as Bat or FireFly algorithms. Presenting the PSO and ACO we put their pseudo-code, their properties and intuition laying behind them. Next, we focus on their real-life applications, indicating many papers presented varieties of basic algorithms and the areas of their applications.

Feature selection is an important data preprocessing step which is performed before a learning algorithm is applied. The issue that has to be taken into consideration when proposing a feature selection method is its computational complexity. Often, if the feature selection process is fast, it cannot thoroughly search the feature subset space and classification accuracy is degraded. Lately, a pairwise feature selection method was proposed as an effective trade-off between computation speed and classification accuracy. In this paper, a new feature selection method is proposed which further improves feature selection speed while preserving classification accuracy. The new method selects features individually or in a pairwise manner based on the correlations between features. Experiments conducted on several benchmark data sets prove with high statistical significance that the correlation-based feature selection method shortens computations compared to the pairwise feature selection method and produces classification errors that are not worse than those produced by existing methods.

One of the main evolutionary algorithms bottlenecks is the significant effectiveness dropdown caused by increasing number of genes necessary for coding the problem solution. In this paper, we present a multi population pattern searching algorithm (MuPPetS), which is supposed to be an answer to situations where long coded individuals are a must. MuPPetS uses some of the messy GA ideas like coding and operators. The presented algorithm uses the binary coding, however the objective is to use MuPPetS against real-life problems, whatever coding schema. The main novelty in the proposed algorithm is a gene pattern idea based on retrieving, and using knowledge of gene groups which contains genes highly dependent on each other. Thanks to gene patterns the effectiveness of data exchange between population individuals improves, and the algorithm gains new, interesting, and beneficial features like a kind of “selective attention” effect.

Real-world optimization problems may have a different underlying structure. In black-box optimization, the dependencies between decision variables remain unknown. However, some techniques can discover such interactions accurately. In Large Scale Global Optimization (LSGO), problems are high-dimensional. It was shown effective to decompose LSGO problems into subproblems and optimize them separately. The effectiveness of such approaches may be highly dependent on the accuracy of problem decomposition. Many state-of-the-art decomposition strategies are derived from Differential Grouping (DG). However, if a given problem consists of non-additively separable subproblems, DG-based strategies may discover many non-existing interactions. On the other hand, monotonicity checking strategies proposed so far do not report non-existing interactions for any separable subproblems but may miss discovering many of the existing ones. Therefore, we propose Incremental Recursive Ranking Grouping (IRRG) that suffers from none of these flaws. IRRG consumes more fitness function evaluations than the recent DG-based propositions, e.g., Recursive DG 3 (RDG3). Nevertheless, the effectiveness of the considered Cooperative Co-evolution frameworks after embedding IRRG or RDG3 was similar for problems with additively separable subproblems that are suitable for RDG3. After replacing the additive separability with non-additive, embedding IRRG leads to results of significantly higher quality.