Sébastien Le Digabel

Calculating optimal conditions for alloy and process design using thermodynamic and property databases, the FactSage software and the Mesh Adaptive Direct Search algorithm

  • Charles Audet
  • Aïmen E. Gheribi
  • Sébastien Le Digabel
  • Arthur D. Pelton
  • Eve Bélisle
    • Categories Applications - Science and Engineering

    During alloy and process design, it is often desired to identify regions of design or process variables for which certain calculated functions have optimal values under various constraints, for example: compositions of minimum liquidus temperature in an N-component alloy; compositions where the amount of precipitate in a given phase is maximized or minimized during annealing … Read more

    Calculating all local minima on liquidus surfaces using the FactSage software and databases and the Mesh Adaptive Direct Search algorithm

  • Charles Audet
  • Aïmen E. Gheribi
  • Sébastien Le Digabel
  • Arthur D. Pelton
  • Christian Robelin
    • Categories Applications - Science and Engineering

    It is often of interest, for a multicomponent system, to identify the low melting compositions at which local minima of the liquidus surface occur. The experimental determination of these minima can be very time-consuming. An alternative is to employ the CALPHAD approach using evaluated thermodynamic databases containing optimized model parameters giving the thermodynamic properties of … Read more

    Trade-off studies in blackbox optimization

  • Charles Audet
  • John E. Dennis, Jr.
  • Sébastien Le Digabel
    • Categories Applications - OR and Management Sciences, Constrained Nonlinear Optimization

    This paper proposes a framework for trade-off analyses of blackbox constrained optimization problems. Two strategies are developed to show the trade-off of the optimal objective function value with tightening or loosening general constraints. These are a simple method which may be performed immediately after a single optimization and a detailed method performing biobjective optimization on … Read more

    The mesh adaptive direct search algorithm for periodic variables

  • Charles Audet
  • Sébastien Le Digabel
    • Categories Applications - OR and Management Sciences, Convex and Nonsmooth Optimization Tags , , , ,

    This work analyzes constrained black box optimization in which the functions defining the problem are periodic with respect to some or all the variables. We show that the natural strategy of mapping trial points into the interval defined by the period in the Mesh Adaptive Direct Search (MADS) framework can be easily done in practice, … Read more

    Algorithm 909: NOMAD: Nonlinear Optimization with the MADS algorithm

  • Sébastien Le Digabel
    • Categories Applications - OR and Management Sciences, Optimization Software and Modeling Systems Tags , , , ,

    NOMAD is software that implements the MADS algorithm (Mesh Adaptive Direct Search) for black-box optimization under general nonlinear constraints. Blackbox optimization is about optimizing functions that are usually given as costly programs with no derivative information and no function values returned for a significant number of calls attempted. NOMAD is designed for such problems and … Read more

    Parallel Space Decomposition of the Mesh Adaptive Direct Search algorithm

  • Charles Audet
  • John E. Dennis, Jr.
  • Sébastien Le Digabel
    • Categories Applications - OR and Management Sciences, Nonsmooth Optimization, Parallel Algorithms Tags , , , ,

    This paper describes a parallel space decomposition PSD technique for the mesh adaptive direct search MADS algorithm. MADS extends a generalized pattern search for constrained nonsmooth optimization problems. The objective of the present work is to obtain good solutions to larger problems than the ones typically solved by MADS. The new method PSD-MADS is an … Read more

    OrthoMADS: A deterministic MADS instance with orthogonal directions

  • Mark A. Abramson
  • Charles Audet
  • John E. Dennis, Jr.
  • Sébastien Le Digabel
    • Categories Applications - OR and Management Sciences, Nonsmooth Optimization Tags , , , ,

    he purpose of this paper is to introduce a new way of choosing directions for the mesh adaptive direct search (Mads) class of algorithms. The advantages of this new OrthoMads instantiation of Mads are that the polling directions are chosen deterministically, ensuring that the results of a given run are repeatable, and that they are … Read more

    Exact and heuristic solutions of the global supply chain problem with transfer pricing

  • Pierre Hansen
  • Sébastien Le Digabel
  • Sylvain Perron
  • Nenad Mladenovic
    • Categories Applications - OR and Management Sciences, Nonlinear Optimization, Supply Chain Management Tags , , , , ,

    We examine the example of a multinational corporation that attempts to maximize its global after tax profits by determining the flow of goods, the transfer prices, and the transportation cost allocation between each of its subsidiaries. Vidal and Goetschalckx (2001) proposed a bilinear model of this problem and solved it by an Alternate heuristic. We … Read more