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- Jason Frank, Cornelis Vuik
- SIAM J. Scientific Computing
- 2001

In this article we introduce new bounds on the e ective condition number of de ated and preconditioned-de ated symmetric positive de nite linear systems. For the case of a subdomain de ation such as that of Nicolaides (1987), these theorems can provide direction in choosing a proper decomposition into subdomains. If grid re nement is done keeping the… (More)

- Jason Frank, Brian E. Moore, Sebastian Reich
- SIAM J. Scientific Computing
- 2006

Multi-symplectic methods have recently been proposed as a generalization of symplectic ODE methods to the case of Hamiltonian PDEs. Their excellent long time behavior for a variety of Hamiltonian wave equations has been demonstrated in a number of numerical studies. A theoretical investigation and justification of multi-symplectic methods is still largely… (More)

- Svetlana Dubinkina, Jason Frank
- J. Comput. Physics
- 2007

The results of statistical analysis of simulation data obtained from long time integrations of geophysical fluid models greatly depend on the conservation properties of the numerical discretization chosen. This is illustrated for quasi-geostrophic flow with topographic forcing, for which a well established statistical mechanics exists. Statistical… (More)

A new particle-mesh method is proposed for the rotating shallow-water equations. The spatially truncated equations are Hamiltonian and satisfy a Kelvin circulation theorem. The generation of non-smooth components in the layer-depth is avoided by applying a smoothing operator similar to what has recently been discussed in the context of -Euler models.

The Hamiltonian particle-mesh (HPM) method is generalized to the spherical shallow water equations, utilizing constrained particle dynamics on the sphere and smoothing with Merilees’ double-periodic FFT formulation of O(J log J) in the latitudinal gridsize. The time step for the explicit, symplectic integrator depends only on the uniform smoothing length.… (More)

- Clifford R Everett, Dmitry Novoseletsky, Sarah Cole, Jason Frank, Christopher Remillard, Rajeev K Patel
- Pain physician
- 2005

BACKGROUND
One of the most important issues that interventional physicians address during treatment is informing patients of their treatment options. Prior to beginning treatment, patients are given this information and allowed the opportunity to ask questions. Minimal qualitative information exists as to how much of this material patients retain and… (More)

- Jason Frank
- 2006

In this paper we discuss the conservation of wave action under numerical discretization by variational and multisymplectic methods. Both the general wave action conservation defined with respect to a smooth, periodic, one-parameter ensemble of flow realizations and the specific wave action based on an approximated and averaged Lagrangian are addressed in… (More)

This paper addresses nonphysical reflections encountered in the discretization of wave equations on nonuniform grids. Such nonphysical solutions are commonly attributed to spurious modes in the numerical dispersion relation. We provide an example of a discretization in which a (nonspurious) physical mode is spuriously energized at a grid nonuniformity. It… (More)

Based on the thermodynamic concept of a reservoir, we investigate a computational model for interaction with unresolved degrees of freedom (a thermal bath). We assume that a finite restricted system can be modelled by a generalized canonical ensemble, described by a density which is a smooth function of the energy of the restricted system. A thermostat is… (More)

- Jason Frank, Sergiy Zhuk
- CDC
- 2014

The paper presents symplectic Möbius integrators for Riccati equations. All proposed methods preserve symmetry, positivity and quadratic invariants for the Riccati equations, and non-stationary Lyapunov functions. In addition, an efficient and numerically stable discretization procedure based on reinitialization for the associated linear Hamiltonian system… (More)