Mikhail Posypkin

Survey of compiler testing methods

Compilers are used for creating executable modules for programs written in high-level languages; therefore, the presence of errors in a compiler is a serious danger for the quality of the software developed with the use of this compiler. As in the case of any other software, testing is one of the most important methods of quality control and error detection in compilers. The survey is devoted to methods for generating, running, and checking the quality of compiler test suites, which are based on formal specifications of the programming language syntax and semantics.Compilers are used for creating executable modules for programs written in high-level languages; therefore, the presence of errors in a compiler is a serious danger for the quality of the software developed with the use of this compiler. As in the case of any other software, testing is one of the most important methods of quality control and error detection in compilers. The survey is devoted to methods for generating, running, and checking the quality of compiler test suites, which are based on formal specifications of the programming language syntax and semantics.

Nonuniform covering method as applied to multicriteria optimization problems with guaranteed accuracy

The nonuniform covering method is applied to multicriteria optimization problems. The ɛ-Pareto set is defined, and its properties are examined. An algorithm for constructing an ɛ-Pareto set with guaranteed accuracy ɛ is described. The efficiency of implementing this approach is discussed, and numerical results are presented.

A deterministic approach to global box-constrained optimization

A deterministic global optimization algorithm for box-constrained problems is presented. The proposed approach is based on well-known non-uniform space covering technique. In the paper this approach is further elaborated. We propose a new techniques that enables a significant reduction of the search space by means of dropping parts of processed boxes. Also a new quadratic underestimation for the objective function based on hessian eigenvalues bounds is presented. It is shown how this underestimation can be improved by exploiting the first-order optimality conditions. In the experimental section we compare the proposed approach with existing methods and programming tools. Numerical tests indicate that the proposed algorithm is highly competitive with considered methods.

Searching of Gapped Repeats and Subrepetitions in a Word

A gapped repeat is a factor of the form uvu where u and v are nonempty words. The period of the gapped repeat is defined as |u| + |v|. The gapped repeat is maximal if it cannot be extended to the left or to the right by at least one letter with preserving its period. The gapped repeat is called α-gapped if its period is not greater than α|u|. A δ-subrepetition is a factor which exponent is less than 2 but is not less than 1 + δ (the exponent of the factor is the quotient of the length and the minimal period of the factor). The δ-subrepetition is maximal if it cannot be extended to the left or to the right by at least one letter with preserving its minimal period. We obtain that in a word of length n the number of maximal α-gapped repeats is bounded by O(α 2 n) and the number of maximal δ-subrepetitions is bounded by O(n/δ 2). Using the obtained upper bounds, we propose algorithms for finding all maximal α-gapped repeats and all maximal δ-subrepetitions in a word of length n. The algorithm for finding all maximal α-gapped repeats has O(α 2 n) time complexity for the case of constant alphabet size and O(nlogn + α 2 n) time complexity for the general case. For finding all maximal δ-subrepetitions we propose two algorithms. The first algorithm has \(O(\frac{n\log\log n}{\delta^2})\) time complexity for the case of constant alphabet size and \(O(n\log n +\frac{n\log\log n}{\delta^2})\) time complexity for the general case. The second algorithm has \(O(n\log n+\frac{n}{\delta^2}\log \frac{1}{\delta})\) expected time complexity.

Parallel logical cryptanalysis of the generator A5/1 in BNB-grid system

In logical cryptanalysis a problem of search of a secret key of a cryptographic system is formulated as a SAT problem, i.e. a problem of search of a satisfying assignment for some CNF. In this paper we consider some natural strategies for parallelization of these SAT problems. We apply coarse-grained approach which makes it possible to use distributed computing environments with slow interconnect. The main practical result of this paper is successful logical cryptanalysis of keystream generator A5/1 in BNB-Grid system.

A deterministic algorithm for global multi-objective optimization

The paper describes a method for solving multi-objective optimization problems with box constraints. Unlike existing approaches, the proposed method not only constructs a finite approximation of Pareto frontier, but also proves its ϵ-optimality. The paper gives a detailed explanation of basic theoretical concepts behind the method and describes the algorithmic implementation. A practically important application of the proposed method to finding the working space of a robotic manipulator is presented.

An application of the nonuniform covering method to global optimization of mixed integer nonlinear problems

The nonuniform covering method for global optimization of functions of several variables is extended to nonlinear programs. It is shown that this method can be used for solving problems that, in addition to conventional constraints, involve partial integrality conditions. Estimates for the accuracy of the solution and for the number of steps required for finding a minimum with a prescribed tolerance are derived. New minorants based on an estimate for the spectrum of the Hessian matrix of the objective function and the constraints are given. New formulas for covering sets improving the efficiency of the method are obtained. Examples of solving nonlinear programs with the use of the proposed approach are presented.

Speedup estimates for some variants of the parallel implementations of the branch-and-bound method

The efficiency of parallel implementations of the branch-and-bound method in discrete optimization problems is considered. A theoretical analysis and comparison of two parallel implementations of this method is performed. A mathematical model of the computation process is constructed and used to obtain estimates of the maximum possible speedup. Examples of problems in which none of these two parallel implementations can speed up the computations are considered.

Coverage-driven Automated Compiler Test Suite Generation

Abstract The paper presents a novel approach to automated compiler test suite generation based on the source level specification. Several coverage criteria are introduced. The application of the proposed methodology to testing the realistic programming language is discussed.

Versions of the Method of Nonuniform Coverings for Global Optimization of Mixed Integer Nonlinear Problems

The method of nonuniform coverings as applied to the global optimization of functions of several variables was proposed in 1971 in [1] and was further developed in numerous works, e.g., in [2]–[5]. Various versions of the method were implemented as software codes and were used for computations on multiprocessor systems [4, 5]. This paper gives a more general treatment of the method than in [1, 2]. The method is applied to the simplest nonlinear programming problem of finding a global isolated minimum. The computations were performed with and without using the integer-valuedness condition. The introduction of this condition led to a considerable reduction in the computation time. Given a continuous function f : R → R, the problem is to find its global minimum on the feasible set X ⊆ R: