Changes between Version 17 and Version 18 of u/erica/PoissonSolver
- Timestamp:
- 08/19/13 13:00:57 (11 years ago)
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u/erica/PoissonSolver
v17 v18 13 13 where u is the dependent variable we are solving for, and f is the forcing term. 14 14 15 The solution to this equation needs to simultaneously 1) satisfy this equation at all points within a bounding region and 2) satisfy the boundary conditions on that region. Thus, this equation + solution can be thought of as an instantaneous system, much different than the wave-like solutions of hyperbolic equations which travel with finite speed. 15 The solution to this equation needs to simultaneously 1) satisfy this equation at all points within a bounding region and 2) satisfy the boundary conditions on that region. Thus, this equation + solution can be thought of as an instantaneous system, much different than the wave-like solutions of hyperbolic equations which travel with finite speed. Indeed, the numerical methods for solving hyperbolic equations compared to elliptic equations are much different. Apart from their classification as either boundary value or initial value problems, they can be thought of as "time-evolution" or "static" problems respectively, from a computational point of view (see Fortran Numerical Recipes, Press et al, Vol. 2, Chapt. 19 - Partial Differential Equations). The following figure from that book illustrates this concept: 16 17 [[Image(PDENumerics.png, 35%)]] 16 18 17 19 Some special cases for elliptic equations occur when [[latex($\kappa = 1$)]]; when f is non-zero, we have the Poisson equation,