nonlinear equations

Approaches to iterative algorithms for solving nonlinear equations with an application in tomographic absorption spectroscopy

  • Francisco J. Aragón Artacho
  • Weiwei Cai
  • Yair Censor
  • Aviv Gibali
  • Chongyuan Shui
  • David Torregrosa-Belén
    • Categories Biomedical Applications, Constrained Nonlinear Optimization, Nonsmooth Optimization Tags , , , , , ,

    In this paper we propose an approach for solving systems of nonlinear equations without computing function derivatives. Motivated by the application area of tomographic absorption spectroscopy, which is a highly-nonlinear problem with variables coupling, we consider a situation where straightforward translation to a fixed point problem is not possible because the operators that represent the … Read more

    Behavior of Newton-type methods near critical solutions of nonlinear equations with semismooth derivatives

  • Andreas Fischer
  • Alexey F. Izmailov
  • Mario Jelitte
    • Categories Nonlinear Optimization, Nonsmooth Optimization Tags , ,

    Having in mind singular solutions of smooth reformulations of complementarity problems, arising unavoidably when the solution in question violates strict complementarity, we study the behavior of Newton-type methods near singular solutions of nonlinear equations, assuming that the operator of the equation possesses a strongly semismooth derivative, but is not necessarily twice differentiable. These smoothness restrictions … Read more

    A globally trust-region LP-Newton method for nonsmooth functions under the Hölder metric subregularity

  • Leticia Becher
  • Damián Fernández
  • Alberto Ramos
    • Categories Constrained Nonlinear Optimization Tags , , , ,

    We describe and analyse a globally convergent algorithm to find a possible nonisolated zero of a piecewise smooth mapping over a polyhedral set, such formulation includes Karush-Kuhn-Tucker (KKT) systems, variational inequalities problems, and generalized Nash equilibrium problems. Our algorithm is based on a modification of the fast locally convergent Linear Programming (LP)-Newton method with a … Read more

    New quasi-Newton method for solving systems of nonlinear equations

  • Ladislav Lukšan
  • Jan Vlček
    • Categories Nonlinear Optimization, Nonlinear Systems and Least-Squares Tags , , , , , ,

    In this report, we propose the new Broyden method for solving systems of nonlinear equations, which uses the first derivatives, but it is more efficient than the Newton method (measured by the computational time) for larger dense systems. The new method updates QR decompositions of nonsymmetric approximations of the Jacobian matrix, so it requires $O(n^2)$ … Read more

    Optimal Deterministic Algorithm Generation

  • Ioannis G. Kevrekidis
  • Alexander Mitsos
  • Jaromił Najman
    • Categories Applications - Science and Engineering, Global Optimization, Other Topics Tags , ,

    A formulation for the automated generation of algorithms via mathematical programming (optimization) is proposed. The formulation is based on the concept of optimizing within a parameterized family of algorithms, or equivalently a family of functions describing the algorithmic steps. The optimization variables are the parameters – within this family of algorithms- that encode algorithm design: … Read more

    Solution of Nonlinear Equations via Optimization

  • Isaac Siwale
    • Categories Applications - OR and Management Sciences, Constrained Nonlinear Optimization, Multi-Criteria Optimization Tags , , , , ,

    This paper presents four optimization models for solving nonlinear equation systems. The models accommodate both over-specified and under-specified systems. A variable endogenization technique that improves efficiency is introduced, and a basic comparative study shows one of the methods presented to be very effective. Citation Siwale, I. (2013). Solution of nonlinear equation systems via optimization. Technical … Read more

    A sufficiently exact inexact Newton step based on reusing matrix information

  • Anders Forsgren
    • Categories Constrained Nonlinear Optimization, Linear Programming, Nonlinear Systems and Least-Squares Tags , ,

    Newton’s method is a classical method for solving a nonlinear equation $F(z)=0$. We derive inexact Newton steps that lead to an inexact Newton method, applicable near a solution. The method is based on solving for a particular $F'(z_{k’})$ during $p$ consecutive iterations $k=k’,k’+1,\dots,k’+p-1$. One such $p$-cycle requires $2^p-1$ solves with the matrix $F'(z_{k’})$. If matrix … Read more

    Adjoint Broyden a la GMRES

  • Andreas Griewank
  • Sebastian Schlenkrich
  • Andrea Walther
    • Categories Nonlinear Systems and Least-Squares Tags , , , , , ,

    It is shown that a compact storage implementation of a quasi-Newton method based on the adjoint Broyden update reduces in the affine case exactly to the well established GMRES procedure. Generally, storage and linear algebra effort per step are small multiples of n k, where n is the number of variables and k the number … Read more

    An Accelerated Newton Method for Equations with Semismooth Jacobians and Nonlinear Complementarity Problems: Extended Version

  • Christina Oberlin
  • Stephen Wright
    • Categories Complementarity and Variational Inequalities, Nonlinear Systems and Least-Squares Tags , ,

    We discuss local convergence of Newton’s method to a singular solution $x^*$ of the nonlinear equations $F(x) = 0$, for $F:\R^n \rightarrow \R^n$. It is shown that an existing proof of Griewank, concerning linear convergence to a singular solution $x^*$ from a starlike domain around $x^*$ for $F$ twice Lipschitz continuously differentiable and $x^*$ satisfying … Read more