The swimpde framework presents an efficient, mesh-free alternative to traditional solvers
for Partial Differential Equations (PDEs) using the ”Sampling Where It Matters” (SWIM)
framework. The motivation for this thesis stems from the need to determine where we
actually require the basis functions for a given simulation. This thesis extends the capa-
bilities of the swimpde framework to robustly solve the 1D and 2D wave equations with
adaptive basis functions. The primary contributions are threefold. First, we identify and
correct the multi-block resampling strategy for second-order time-dependent PDEs, ensur-
ing that the full physical state, including time derivatives (u and ut ), is correctly transferred
between blocks. Second, we implement an adaptive resampling method for 2D problems
by implementing a flexible acceptance-rejection sampling algorithm, moving beyond the
limitations of the 1D inverse transform method. Third, we develop a new, robust probabil-
ity density function (PDF) for resampling. This new PDF incorporates a Gaussian filter to
smooth the solution gradients, which has proven essential for stable tracking of oscillatory
wavefronts and preventing error amplification upon reflection, a problem that plagued
naive gradient-based approaches.
These contributions are validated through a series of numerical experiments. The en-
hanced solver accurately matches analytical solutions for 1D and 2D wave propagation
problems, which include a 1D reflecting Gaussian pulse and a 2D droplet simulation. The
results demonstrate that the new PDF is efficient in terms of numerical stability for reflec-
tion problems, and the 2D resampling strategy effectively captures complex, propagating
wave patterns for 2D wave problems.
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The swimpde framework presents an efficient, mesh-free alternative to traditional solvers
for Partial Differential Equations (PDEs) using the ”Sampling Where It Matters” (SWIM)
framework. The motivation for this thesis stems from the need to determine where we
actually require the basis functions for a given simulation. This thesis extends the capa-
bilities of the swimpde framework to robustly solve the 1D and 2D wave equations with
adaptive basis functions. The primary contributions are t...
»