Making Adaptive an Interval Constraint Propagation Algorithm Exploiting Monotonicity

International audienceA new interval constraint propagation algorithm, called MOnotonic Hull Consistency (Mohc), has recently been proposed. Mohc exploits monotonicity of functions to better filter variable domains. Embedded in an interval-based solver, Mohc shows very high performance for solving systems of numerical constraints (equations or inequalities) over the reals. However, the main drawback is that its revise procedure depends on two user-defined parameters. This paper reports a rigourous empirical study resulting in a variant of Mohc that avoids a manual tuning of the parameters. In particular, we propose a policy to adjust in an auto-adaptive way, during the search, the parameter sensitive to the monotonicity of the revised function

Hull Consistency Under Monotonicity

International audienceWe prove that hull consistency for a system of equations or inequalities can be achieved in polynomial time providing that the underlying functions are monotone with respect to each variable. This result holds including when variables have multiple occurrences in the expressions of the functions, which is usually a pitfall for interval-based contractors. For a given constraint, an optimal contractor can thus be enforced quickly under monotonicity and the practical significance of this theoretical result is illustrated on a simple example

Specifying the micro-program parallelism for microprocessors of the Von Neumann style

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Comparing Partial Consistencies

. Global search algorithms have been widely used in the constraint programming framework to solve constraint systems over continuous domains. This paper precisely states the relations among the different partial consistencies which are main emphasis of these algorithms. The capability of these partial consistencies to handle the so-called dependency problem is analysed and some efficiency aspects of the filtering algorithms are mentioned. Keywords: Constraint systems, interval narrowing, partial consistencies 1. Introduction Global search algorithms that are based upon partial consistency filtering techniques have proven their efficiency to solve non-trivial constraint systems over the reals. For instance, systems like Newton and Numerica [2, 28] behave better than interval methods on classical benchmarks of numerical analysis and interval analysis (e.g., Mor'e-Cosnard non-linear integral equation, Broyden banded functions). Moreover, it has been shown recently [9] that combining alg..

muSPEED : a framework for specifying and verifying microprocessors

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muSPEED : a framework for specifying and verifying microprocessors

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Parallel Implementation of Interval Analysis for Equations Solving

International audienceALIAS is a C++ library implementing interval analysis and constraint programming methods for studying and solving set of equation over the reals. In this paper, we describes a distributed implementation of the library

Functional modelling and testing of digital circuits

The approach suggested by a team engaged in augmentation of simulated circuit validation by automatic testing is explained with reference to a functional model and three automatic demonstration software packages: a tautology demonstrator, a Boyer & Moore theorem prover, and an OBJ3 rewriting-rule-based system. The performances and fields of application of these tools for automatic testing of digital systems are assessed

Int J Softw Tools Technol Transfer DOI 10.1007/s10009-012-0258-6 REGULAR PAPER Constraint-based BMC: a backjumping strategy

Abstract Safety property checking is mandatory in the validation process of critical software. When formal verification tools fail to prove some properties, the automatic generation of counterexamples for a given loop depth is an important issue in practice. We investigate in this paper the capabilities of constraint-based bounded model checking for program verification and counterexample generation on real applications. We introduce dynamic post-condition variable-driven strategy (DPVS), a new backjumping strategy we developed to handle an industrial application from a car manufacturer, the Flasher Manager. This backjumping strategy is used to search a faulty path and to collect the constraints of such a path. The simplified control flow graph (CFG) of the program is explored in a backward way, starting from the post-condition and jumping to the most promising nod