In this book we discuss a class of time discretization techniques, which aretermed strong stability preserving (SSP) time discretizations and have beendeveloped over the past 20 years as an effective tool for solving certain typesof large ordinary differential equation (ODE) systems arising from spatialdiscretizations of partial differential equations (PDEs).The numerical solution of ODEs is of course an established research area.There are many well-studied methods, such as Runge–Kutta methods andmultistep methods. There are also many excellent books on this subject,for example [8, 64, 83]. ODE solvers for problems with special stabilityproperties, such as stiff ODEs, are also well studied, see, e.g., [32, 17].The SSP methods are also ODE solvers, therefore they can be analyzedby standard ODE tools. However, these methods were designed specificallyfor solving the ODEs coming from a spatial discretization of time-dependentPDEs, especially hyperbolic PDEs. The analysis of SSP methods can befacilitated when this background is taken into consideration.In the one-dimensional scalar case, a hyperbolic conservation law isgiven byut + f(u)x = 0 (1.1)where u is a function of x and t, and the subscripts refer to partial derivatives;for example, ut = ∂u∂t . Hyperbolic PDEs pose particular difficultiesfor numerical methods because their solutions typically contain discontinuities.We refer the readers to, e.g. the book of Smoller [94] and the lecturenotes of LeVeque [68] for an introduction to hyperbolic conservation lawsand their numerical solutions. We would like to find a numerical approximation,still denoted by u with an abuse of notation, which discretizes thespatial derivative (e.g. f(u)x in (1.1)) in the PDE. The result is then a
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