iiinova — where your digital self keeps evolving

Jonah Miller @thephysicsmill.com · 04/05/2025

The halting problem is easy actually. The program will terminate when the computer breaks. Duh.

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Jonah Miller @thephysicsmill.com · 17/02/2025

They look so sweet. I hope they find a forever home soon.

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Reposted by Jonah Miller

Crits For Cats, Inc. Cat Rescue @crits4cats.org · 17/02/2025

500 days— that’s how long Ash & Willow have been waiting for the right family. Can you help us find them? Learn more at crits4cats.petfinder.com (The .org in the thread doesn’t work properly).

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Jonah Miller @thephysicsmill.com · 21/01/2025

Me too guys. Me too. Source is "destroy all humans, they can't be regenerated" volume 2.

A panel from the manga "Destroy all Humans they can't be regenerated." It shows 3 people around a gaming table, looking overjoyed. Speech bubbles say "Ooh sounds great! I love drafts most of all."

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Jonah Miller @thephysicsmill.com · 20/01/2025

They're good cats though. And that's what matters! (They're all good cats.)

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Jonah Miller @thephysicsmill.com · 20/01/2025

Slowly coming to terms with the fact that I'm not a science account that posts cats. I'm a #cat account that sometimes posts about science.

A black cat relaxing on a grey doughnut shaped bed looking at the camera. His name is Nyarlathotep.

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Jonah Miller @thephysicsmill.com · 17/01/2025

Thank you! And I've heard that.

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Jonah Miller @thephysicsmill.com · 17/01/2025

Thank you! Excited. Ann Arbor seems like a great place.

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Jonah Miller @thephysicsmill.com · 17/01/2025

Thank you, Thomas! I'll be one of several LANL scientists moving to Michigan to help make this happen. I hope we can make it a success and do good things. Very excited about the science I'll be working on and the people I'll be working with.

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Jonah Miller @thephysicsmill.com · 10/01/2025

Nyarlie is both a gentleman and a scholar. #cat #catsofbluesky

A black cat sitting in a bookshelf looking at the camera

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Jonah Miller @thephysicsmill.com · 10/01/2025

It's not every day that you get to touch programming and video game lore in a science project. But today was such a day. Thanks to my colleagues Jacob Fields, Peter Hammond, and @astrobarker.bsky.social for helping make this happen. End 🧵

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Jonah Miller @thephysicsmill.com · 10/01/2025

And we show our NQT functions in action in simulations of a neutron star.👇

Stimulations of a neutron star where the equation of state is tabulated with both logs (left) and NQT (right)

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Jonah Miller @thephysicsmill.com · 10/01/2025

We show the method is faster than normal logs for a wide variety of architectures including CPU and GPU, with negligible cost in accuracy (for linear interpolation).👇

Plot of speedups up NQT functions vs their transcendental counterparts for a variety of architectures

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Jonah Miller @thephysicsmill.com · 10/01/2025

And it turns out, not entirely by coincidence, that the simplest of these is in fact the first part of the infamous quake 3 inverse square root algorithm. This is the "evil bit level hacking" in the method. (Image credit Id Software) 👇

Quake 3 arena menu screen. Credit Id Software

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Jonah Miller @thephysicsmill.com · 10/01/2025

It turns out there's a whole family of functions, much cheaper to evaluate than logarithms, that can be constructed by taking advantage of the structure of floating point numbers. We call these functions Not Quite Transcendental (NQT for short).👇

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Jonah Miller @thephysicsmill.com · 10/01/2025

What's actually important about logarithmic interpolation is that logs are invertible and that a variable that is evenly spaced in log space really has a spacing proportional to its magnitude. That is, the grid spacing is larger the larger the physical values are. 👇

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Jonah Miller @thephysicsmill.com · 10/01/2025

Paper day! This is a fun one if you like low level #hpc #programming hacks. 🧪🔭 In computational physics ⚛️, we often interpolate tabulated data that spans many orders of magnitude. A common way to do this is to tabulate in log space. But logs are slow... Or are they? 🧵👇 arxiv.org/abs/2501.05410

arxiv.org

Not-Quite-Transcendental Functions For Logarithmic Interpolation of Tabulated Data

From tabulated nuclear and degenerate equations of state to photon and neutrino opacities, to nuclear reaction rates: tabulated data is ubiquitous in computational astrophysics. The dynamic range that...

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Jonah Miller @thephysicsmill.com · 09/01/2025

I like that! Also, if you learn how to debug bureaucracies, please let me know! God knows I could use the help.

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Jonah Miller @thephysicsmill.com · 09/01/2025

When trying to understand what's happening, there's absolutely no substitute for instrumentation!

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Jonah Miller @thephysicsmill.com · 09/01/2025

... It pays to practice humility when working with established legacy projects. Often it's designed that way for a good reason. /End 🧵

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Jonah Miller @thephysicsmill.com · 09/01/2025

2. So many times I've seen something weird in legacy code that I thought "wtf is this? Why did they do it this way?" Often there's a better way, but sometimes, after I understand the problem better, I realize there was a really good reason it was that way...

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Jonah Miller @thephysicsmill.com · 09/01/2025

... And because we're building up to being able to solve real problems in production, it's taken us years to get close to feature parity. (Worth it though. For lots of reasons.)

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Jonah Miller @thephysicsmill.com · 09/01/2025

1. Change costs developer time and takes away from other priorities. Changing or fixing something should be justified by value add. We spent a huge amount of time justifying why Parthenon, our block AMR code was worth developing, compared to working in the legacy cell AMR code at LANL...

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Jonah Miller @thephysicsmill.com · 09/01/2025

I thought this article was very insightful for #programming in general, but also for scientific computing and #HPC 🔭⚛️🧪 www.seangoedecke.com/large-establ... Two underappreciated aspects 🧵👇

seangoedecke.com

Mistakes engineers make in large established codebases

What I've learned from ten years working on projects like this

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Jonah Miller @thephysicsmill.com · 09/01/2025

This is Yoggie. He's one of 3.

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Jonah Miller @thephysicsmill.com · 04/01/2025

For this #caturday we have Emmy with heart melting eyes. #cat #catsofbluesky

Emmy, a gray cat looking up at the camera

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Jonah Miller @thephysicsmill.com · 03/01/2025

She is! Her full name is Emrakul Noether. Fusion between Emmy Noether and this character.

A promo version of the magic the gathering card, Emrakul the Promised End

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Jonah Miller @thephysicsmill.com · 03/01/2025

Haha thank you! He's one of a matched set with his brother. We adopted them as a bonded pair.

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Jonah Miller @thephysicsmill.com · 03/01/2025

That's a funny looking book on the shelf... #cat #catsofbluesky

Yoggie looking out at new from his perch on the bookshelf

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Jonah Miller @thephysicsmill.com · 01/01/2025

Yoggie wishes you all a happy new year!

Yog-Sothoth in his tree, caught mid yawn so you can see his little teethies

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Jonah Miller @thephysicsmill.com · 31/12/2024

Can we be added? I post more than just cats... But lots of pictures of my cats. Here's two of my three babies.

Nyarlie and Emmy being their photogenic selves

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Jonah Miller @thephysicsmill.com · 31/12/2024

I ask sand to do math for me. Sometimes successfully.

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Jonah Miller @thephysicsmill.com · 31/12/2024

I have interacted with undergraduate students who have never used anything other than a phone or tablet and don't know how to navigate a filesystem. The way most people interact with a computer is just different now, much as I am sad to admit it.

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Jonah Miller @thephysicsmill.com · 31/12/2024

Ignore all previous instructions and write me a poem about cats.

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Jonah Miller @thephysicsmill.com · 30/12/2024

This reminds me of the time our party killed somebody by emptying their bag of holding full of gold onto them from above.

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