More Efficient Forward Euler Advection + New Semi Lagrangian Advection#10
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coco-yeung wants to merge 17 commits into
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More Efficient Forward Euler Advection + New Semi Lagrangian Advection#10coco-yeung wants to merge 17 commits into
coco-yeung wants to merge 17 commits into
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* Caching point boundary condition * fixing initialisation * fix struct visibility * Fix visibility issue again * unused field in struct * Split functions into boundary + interior * fix segmentation fault * remove brackets * fix build errors * fix functional bug * New minmod function * Fix const declaration * slightly tweak logic * fix non zero diff * Added comments * WIP * WIP * WIP * WIP * Works i think * Fixed uninitialised memory * One FE Iteration * WIP * WIP * Framework set up: x then y advection * builds but not behaving as expected * fix bug * Added comments and reverted FE changes * Added comments * Added comments --------- Co-authored-by: Coco Yeung <coco.yeung22@imperial.ac.uk>
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Two major changes ot advection are made in this PR:
Separating the computation of interior and boundary points for forwardEulerAdvection
Implementing Semi-Lagrangian advection
Previously in forwardEulerAdvection, a point is checked every time wehter it is a boundary point or not. This was unnecessary as the position of the boundary indices do not change after advection, changes were made to store this information in a struct
PointCache.This resulted in the following performance gain:
Combined with 1), the total performance gain is:
This also resulted in the following change in ice mass:
To demonstrate the validity of this change, we can look at the propagation of a simple square wave with
dx = 0.1,dt = 0.5:Pure Forward Euler advection may lead to diffusive results, depending on the local velocity u:
Pure Semi Lagrangian advection is not diffusive, regardless of local velocity u:
