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7 replies

Marvee Amasi

Debugging Numerical Instability in AVX512-Optimized 2D Fluid Simulation on x86-64 CPU

In the process of me optimizing a 2D fluid simulation for x86-64 CPU using AVX512 instructions, Intel Xeon architecture , scalable processor with AVX512 support, GCC 12 compiler with

-O3

-O3

optimization flags having periodic boundary conditions using explicit euler time stepping s heme I've implemented a staggered grid-based approach with a finite difference method for calculating fluid forces, but I'm encountering numerical instability issues when simulating large-scale fluid dynamics.

Here is my AVX512 optimized force calculation kernel

Solution

@Marvee Amasi It sounds like you're running into stability issues with your fluid simulation, especially with the explicit

Euler scheme

Euler scheme

on a large grids, to address the numerical instability, try reducing the time step or switching to a more stable method like

implicit Euler

implicit Euler

. Make sure your time step meets the CFL condition to avoid instability.

r-check your periodic boundary conditions for errors, and be cautious with

AVX512

AVX512

optimizations, as they can amplify floating-point precision issues. The

Floating point exception

Floating point exception

could indicate division by zero or overflow, so make sure your calculations are well-guarded.

To debug, simplify your simulation or use tools like

valgrind

valgrind

and

gdb

gdb

to catch errors. These steps should help stabilize your simulation.

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