ChrisFoster

5 ms·

1.
by ChrisFoster 4y ago
Exactly my thought too. The offset is just the zero frequency. But in general, the need to do this for the zero frequency would suggest that there's a scaling problem for all the longer frequency Fourier components? And that, perhaps,
2.
by ChrisFoster 4y ago
I'm not sure we're disagreeing here? As I understand it, some people have a certain kind of distractable brain and there's an underlying brain chemistry implicated here which isn't something you develop in adulthood. How
3.
by ChrisFoster 4y ago
ADHD is a developmental condition which is highly genetic and relates to neurotransmitter brain chemistry (Dopamine / Norepinephrine). People with ADHD have it their whole life, it's not something you can develop in adulthood. How
4.
by ChrisFoster 5y ago
This is from to the history of how the Julia language was bootstrapped. The fact that Jeff happened to have written his own scheme (femtolisp) as a previous project probably helped :-) Actually it's not just the parser but most of the
5.
by ChrisFoster 5y ago
That's biologically impossible, but we might end up with weeds which resemble the crop in new and interesting ways. This has already happened in history for weeds which came under artificial selective pressure due to practices of separ
6.
by ChrisFoster 5y ago
I used to think this was true (as a developer of a lot of generic Julia code and small data analysis applications). But now as a developer of larger amounts of "application style" code, I'm not so sure. In an application, you
7.
by ChrisFoster 5y ago
Have you tried Infiltrator.jl? It's great for breaking out into an interactive REPL from some inner scope, allowing you to examine the local variables and other program state interactively. This covers the part of the functionality of
8.
by ChrisFoster 5y ago
Yes, well put. I'd take it further - in numerical code there is no real distinction /at all/ between closed form vs iterative solutions. Every type of numerical code is subject to truncation error; an iterative method with fe
9.
by ChrisFoster 6y ago
This is really neat. In the past I've used similar techniques to decode binary data from a third party lidar system in parallel. In a way that the manufacturers probably didn't intend or expect. The system generated large data fil
10.
by ChrisFoster 6y ago
> it makes a mess of your system that is hard to clean up This was true in the past, but the Julia ecosystem has rapidly moved away from installing anything via system package managers or messing with the system state in hard to understa
11.
by ChrisFoster 6y ago
The piston idea seems like a appealing design requiring minimal new technology. The plant is the same as existing pumped hydro plant, the weight can come from the native rock. Using a rolling membrane for the seal is discussed at https:&#x
12.
by ChrisFoster 6y ago
No, I'd say it was an almost-complete success. The point of this was to test several things which they've never tested before and gather data to drive design improvements. They successfully tested: ascent under three engines, flap
13.
by ChrisFoster 6y ago
Punning through the union is explicitly allowed in the GCC documentation which explains why it's reliable for use in the Linux kernel. See https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#Typ... >
14.
by ChrisFoster 6y ago
Actually the heat arises from the natural decay of radioactive elements within the Earth. In the far future it will be gone! It's true that in the early history of the Earth there would have been heating from gravitational contraction
15.
by ChrisFoster 6y ago
> A function does not spring into existence until the definition of the function is executed. Methods and their type signatures do exist within the runtime as soon as the function expression is evaluated. To simplify the example from you
16.
by ChrisFoster 6y ago
I liked the following blog post where Jack Lindamood argues pretty convincingly against using Context.Value in nearly all circumstances, and gives some nice alternatives. https://medium.com/@cep21/how-to-correctly-use-c
17.
by ChrisFoster 6y ago
Agreed, treating log events as a string seems like throwing a lot of readily available information away. There's various logging libraries which do allow more structure but too often this is ignored. I think we got some of this right i
18.
by ChrisFoster 6y ago
I agree the exterior algebra is beautifully elegant mathematics, but expressive elegance of the formalism is largely irrelevant to numerical robustness. (Cramer's rule itself is a perfect example of this: it's elementary to expres
19.
by ChrisFoster 6y ago
In terms of engineering, I can't see how steering this beam would be remotely viable: it appears you've got to line up the long axes of the 1000 km circumference muon ring to point exactly in the direction of the weapon to be targ
20.
by ChrisFoster 6y ago
My main concern with this comparison is that there's no mention of numerical stability / accuracy of this method. Calculating determinants is notoriously prone to cancellation error if done naively, so you've got to be really
21.
by ChrisFoster 6y ago
"Static" is a reference to the size of the arrays being fixed and encoded in the type. There's various allocation strategies, for instance StaticArrays.SizedArray uses a normal heap-allocated Array as the storage. That said,
22.
by ChrisFoster 6y ago
A year or so I looked into "git for data" for medical research data curation. At the time I found a couple of promising solutions based on wrapping git and git annex: GIN: https://gin.g-node.org/ datalad: https:&
23.
by ChrisFoster 7y ago
Current MR physicist / data scientist here. There seems to be a lot of misapprehension in this thread. First, this work is about taking data in the sensor domain ("k-space") and reconstructing it into an image. Doing this wit
24.
by ChrisFoster 7y ago
Julia has been excellent for shelling out since almost the beginning. See https://julialang.org/blog/2012/03/shelling-out-sucks
25.
by ChrisFoster 7y ago
The models you'd use for map making are often really simple. For example, the Australian plate motion model is a "seven parameter transformation" - three translations, three rotations and a scale factor. The deformation error
26.
by ChrisFoster 7y ago
In principle this is actually quite a reasonable idea and is a common pattern of many types of physical measurement. Often we have a detailed and accurate physical model of the forward dynamics of a system, given some system parameters, but
27.
by ChrisFoster 7y ago
Have you seen https://github.com/sciapp/gr ?
28.
by ChrisFoster 7y ago
This is pretty neat work, I was considering using it to help work around the problems of anisotropically scaled SDF font rendering. (Trick: do the anisotropic scaling and add the Jacobian correction factor per color channel before combining
29.
by ChrisFoster 7y ago
This has been vastly improved fairly recently with the advent of the tensorflow-gpu meta package available via conda. See https://towardsdatascience.com/tensorflow-gpu-installation-m...
30.
by ChrisFoster 7y ago
In terms of hiding an emitter, the relevant quantity is the beam solid angle in the far field. This is wavelength dependent which implies temperature dependence if we're talking thermal radiation. The lower the temperature, the longer

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