THE HEAVY BALL WITH FRICTION METHOD, I. THE CONTINUOUS DYNAMICAL SYSTEM: GLOBAL EXPLORATION OF THE LOCAL MINIMA OF A REAL-VALUED FUNCTION BY ASYMPTOTIC ANALYSIS OF A DISSIPATIVE DYNAMICAL SYSTEM

2000 ◽  
Vol 02 (01) ◽  
pp. 1-34 ◽  
Author(s):  
H. ATTOUCH ◽  
X. GOUDOU ◽  
P. REDONT
Keyword(s):  
Dynamical System ◽  
Critical Point ◽  
Real Hilbert Space ◽  
Unconstrained Minimization ◽  
Cauchy Data ◽  
Local Minima ◽  
Lipschitz Continuous ◽  
Singular Perturbation Analysis ◽  
Dissipative Dynamical System ◽  
Heavy Ball With Friction

Let H be a real Hilbert space and Φ:H ↦ R a continuously differentiable function, whose gradient is Lipschitz continuous on bounded sets. We study the nonlinear dissipative dynamical system: [Formula: see text], plus Cauchy data, mainly in view of the unconstrained minimization of the function Φ. New results concerning the convergence of a solution to a critical point are given in various situations, including when Φ is convex (possibly with multiple minima) or is a Morse function (the critical point being then generically a local minimum); a counterexample shows that, without peculiar assumptions, a trajectory may not converge. By following the trajectories, we obtain a method for exploring local minima of Φ. A singular perturbation analysis links our results with those concerning gradient systems.

scholarly journals ASYMPTOTICS FOR A DISSIPATIVE DYNAMICAL SYSTEM WITH LINEAR AND GRADIENT-DRIVEN DAMPING

2013 ◽  
Vol 18 (5) ◽  
pp. 654-674
Author(s):  
Yuhu Wu ◽  
Xiaoping Xue
Keyword(s):  
Dynamical System ◽  
Hilbert Space ◽  
Asymptotic Behavior ◽  
Real Hilbert Space ◽  
Nonlinear Damping ◽  
Second Order ◽  
Differentiable Functions ◽  
Dissipative Dynamical System

We study, in the setting of a real Hilbert space H, the asymptotic behavior of trajectories of the second-order dissipative dynamical system with linear and gradient-driven nonlinear damping where λ > 0 and f, Φ: H → R are two convex differentiable functions. It is proved that if Φ is coercive and bounded from below, then the trajectory converges weakly towards a minimizer of Φ. In particular, we state that under suitable conditions, the trajectory strongly converges to the minimizer of Φ exponentially or polynomially.

Dynamical system approach for the modified Brans–Dicke theory

2019 ◽  
Vol 28 (10) ◽  
pp. 1950132 ◽  
Author(s):  
Jianbo Lu ◽  
Xin Zhao ◽  
Shining Yang ◽  
Jiachun Li ◽  
Molin Liu
Keyword(s):  
Dynamical System ◽  
Dark Energy ◽  
Critical Point ◽  
System Approach ◽  
State Parameter ◽  
Kinetic Term ◽  
De Sitter ◽  
Dynamical System Approach ◽  
De Sitter Universe ◽  
Manifold Theory

A modified Brans–Dicke theory (abbreviated as GBD) is proposed by generalizing the Ricci scalar [Formula: see text] to an arbitrary function [Formula: see text] in the original BD action. It can be found that the GBD theory has some interesting properties, such as solving the problem of PPN value without introducing the so-called chameleon mechanism (comparing with the [Formula: see text] modified gravity), making the state parameter to crossover the phantom boundary: [Formula: see text] without introducing the negative kinetic term (comparing with the quintom model). In the GBD theory, the gravitational field equation and the cosmological evolutional equations have been derived. In the framework of cosmology, we apply the dynamical system approach to investigate the stability of the GBD model. A five-variable cosmological dynamical system and three critical points ([Formula: see text], [Formula: see text], [Formula: see text]) are obtained in the GBD model. After calculation, it is shown that the critical point [Formula: see text] corresponds to the radiation dominated universe and it is unstable. The critical point [Formula: see text] is unstable, which corresponds to the geometrical dark energy dominated universe. While for case of [Formula: see text], according to the center manifold theory, this critical point is stable, and it corresponds to geometrical dark energy dominated de Sitter universe ([Formula: see text]).

scholarly journals An Active Set Smoothing Method for Solving Unconstrained Minimax Problems

2020 ◽  
Vol 2020 ◽  
pp. 1-25
Author(s):  
Zhengyong Zhou ◽  
Qi Yang
Keyword(s):  
Minimax Problems ◽  
Unconstrained Minimization ◽  
Smoothing Method ◽  
Smoothing Function ◽  
Active Set ◽  
Maximum Function ◽  
Minimization Method ◽  
Lipschitz Continuous ◽  
Locally Lipschitz ◽  
Smoothing Parameters

In this paper, an active set smoothing function based on the plus function is constructed for the maximum function. The active set strategy used in the smoothing function reduces the number of gradients and Hessians evaluations of the component functions in the optimization. Combing the active set smoothing function, a simple adjustment rule for the smoothing parameters, and an unconstrained minimization method, an active set smoothing method is proposed for solving unconstrained minimax problems. The active set smoothing function is continuously differentiable, and its gradient is locally Lipschitz continuous and strongly semismooth. Under the boundedness assumption on the level set of the objective function, the convergence of the proposed method is established. Numerical experiments show that the proposed method is feasible and efficient, particularly for the minimax problems with very many component functions.

Three Conditions Lyapunov Exponents Should Satisfy

2003 ◽  
Author(s):  
Jingjun Lou ◽  
Shijian Zhu
Keyword(s):  
Dynamical System ◽  
Fixed Point ◽  
Lyapunov Exponent ◽  
Lyapunov Exponents ◽  
Chaotic Motion ◽  
The Other ◽  
Cubic Nonlinearity ◽  
3 Dimensional ◽  
Duffing System ◽  
Dissipative Dynamical System

In contrast to the unilateral claim in some papers that a positive Lyapunov exponent means chaos, it was claimed in this paper that this is just one of the three conditions that Lyapunov exponent should satisfy in a dissipative dynamical system when the chaotic motion appears. The other two conditions, any continuous dynamical system without a fixed point has at least one zero exponent, and any dissipative dynamical system has at least one negative exponent and the sum of all of the 1-dimensional Lyapunov exponents id negative, are also discussed. In order to verify the conclusion, a MATLAB scheme was developed for the computation of the 1-dimensional and 3-dimensional Lyapunov exponents of the Duffing system with square and cubic nonlinearity.

Adding machines and wild attractors

1997 ◽  
Vol 17 (6) ◽  
pp. 1267-1287 ◽  
Author(s):  
HENK BRUIN ◽  
GERHARD KELLER ◽  
MATTHIAS ST. PIERRE
Keyword(s):  
Dynamical System ◽  
Critical Point ◽  
Cantor Set ◽  
Limit Set ◽  
Unimodal Maps ◽  
Irrational Rotations ◽  
Circle Rotation ◽  
Omega Limit Set ◽  
Adding Machines

We investigate the dynamics of unimodal maps $f$ of the interval restricted to the omega limit set $X$ of the critical point for cases where $X$ is a Cantor set. In particular, many cases where $X$ is a measure attractor of $f$ are included. We give two classes of examples of such maps, both generalizing unimodal Fibonacci maps [LM, BKNS]. In all cases $f_{|X}$ is a continuous factor of a generalized odometer (an adding machine-like dynamical system), and at the same time $f_{|X}$ factors onto an irrational circle rotation. In some of the examples we obtain irrational rotations on more complicated groups as factors.

Catastrophes with indeterminate outcome

1991 ◽  
Vol 432 (1884) ◽  
pp. 113-123 ◽  
Keyword(s):  
Dynamical System ◽  
Phase Space ◽  
Invariant Manifolds ◽  
Space Geometry ◽  
Dissipative Dynamical System ◽  
Forced Oscillators ◽  
Phase Space Geometry

A catastrophe in a dissipative dynamical system which causes an attractor to completely lose stability will result in a transient trajectory making a rapid jump in phase space to some other attractor. In systems where more than one other attractor is available, the attractor chosen may depend very sensitively on how the catastrophe is realized. Two examples in forced oscillators of Duffing type illustrate how the probabilities of different outcomes can be estimated using the phase space geometry of invariant manifolds.

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