We propose a method to approximate numerically the diffusion of an age-structured population in a spatial environment. We integrate separately the age and time variables by finite differences and we discretize the space variable by finite elements. The method is implicit in time and, inside each time step, implicit in age. We provide stability and convergence results and we illustrate our appro...

The basic ideas of semi-implicit time differencing are reviewed, including analytical results not widely referenced in the meteorological literature. It is shown that solving the resulting implicit equations by simple fixed-point iteration requires a relatively small time step to guarantee convergence, thus defeating the purpose of the semiimplicit method. In contrast, classical iteration metho...

This paper presents a semi-analytical method for periodic flows in continuous nonlinear dynamical systems. For the semi-analytical approach, differential equations of nonlinear dynamical systems are discretized to obtain implicit maps, and a mapping structure based on the implicit maps is employed for a periodic flow. From mapping structures, periodic flows in nonlinear dynamical systems are pr...

Linearly-implicit two-step peer methods are successfully applied in the numerical solution of ordinary differential and differential-algebraic equations. One of their strengths is that even highorder methods do not show order reduction in computations for stiff problems. With this property, peer methods commend themselves as time-stepping schemes in finite element calculations for timedependent...

A new family of linearly implicit fractional step methods is proposed for the efficient numerical solution of a class of nonlinear time-dependent reaction-diffusion equations. By using the method of lines, the original problem is first discretized in space via a mimetic finite difference technique. The resulting differential system of stiff nonlinear equations is locally decomposed by suitable ...

We report a class of stabilized explicit-implicit domain decomposition (SEIDD) methods for the numerical solution of parabolic equations. Explicit-implicit domain decomposition (EIDD) methods are globally noniterative, nonoverlapping domain decomposition methods, which, when compared with Schwarz-algorithm-based parabolic solvers, are computationally and communicationally efficient for each sim...

Computational study of the macroscopic stability of plasmas is a challenging multi-scale problem. Implicit time integration can be used to relieve stability constraints due to fast Alfvén waves, and adaptive mesh refinement (AMR) can be used to resolve highly localized solution features. The strong nonlinearities and numerical stiffness of magnetohydrodynamics (MHD) models present further chall...