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I began my journey into programming physics engines and solvers about 7 years ago now, whilst an active Senior Mechanical Engineer in London, UK.

It was excruciatingly painful but equally rewarding in a variety of ways…
(It definitely tested my resolve and commitment to learn!)

It led me down various rabbit holes (which I’ve not quite climbed out of years on!):

  • Computational mechanics

  • Geometry mathematics

  • Graphics pipelines

  • CPU and GPU architecture

  • Software patterns

  • Debugging code

  • Performance tuning

  • …

Honestly, it’s a lot to take on, especially when balancing a full-time job and family commitments.

But I did it anyway and I’m glad I did.

Here’s an earlier engine I built for granular physics in C++, (click to view the video):

I’ve always looked at the career change as more of an adaptation and augmentation of my Engineering design skills.

I can now develop useful digital tools, potentially improving the design and simulation tools out there!

This was and is still a huge plus for me.

A little coding experiment…

I keep pushing myself to keep learning and developing my skills as a professional Software Engineer in this space.

This week I wrote a small program, just to highlight the difference optimised code makes to a theoretical solver code.

Program 1 (Unoptimised memory layout)
Total time for 100 time steps: 636.793 ms
Sample Particle [0] Position: (5, 45.046)

Program 2 (Optimised memory layout)
Total time for 100 time steps: 136.881 ms
Sample Particle [0] Position: (5, 45.046)

That’s a 4.5x speed-up by considering how to layout particle data in RAM!

OpenFOAM code

Analysis of inflow conditions on the flow past a wall-mounted square cylinder with OpenFOAM, ref: Mijian Li, Rui Wang, Xinyu Guo, Xinyu Liu, Lianzhou Wang, [2023]

It’s was released over 20 years ago and written in an C++ object-oriented.

For a variety of reasons It’s slow, but remember the fundamental physics don’t really change.

I love the code for what it is and it’s very good as a generalised system solving fluid dynamics problems in Research and Engineering.

It reminds us that the period of invention, state of technology and collaborative efforts push human community forward.

Here’s a shout-out to OpenFOAM and all those involved…Kudos for bringing a much-loved and respected code-base to the people that need it!

See you soon. 👋
Nasser

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