@robryk@qoto.org avatar

robryk

@robryk@qoto.org

I enjoy things around information theory (and data compression), complexity theory (and cryptography), read hard scifi, currently work in infosec, am somewhat literal minded and have approximate knowledge of random things. I like when statements have truth values, and when things can be described simply (which is not exactly the same as shortly) and yet have interesting properties.

I live in the largest city of Switzerland (and yet have cow and sheep pastures and a swimmable lake within a few hundred meters of my place :)). I speak Polish, English, German, and can understand simple Swiss German and French.

If in doubt, please err on the side of being direct with me. I very much appreciate when people tell me that I'm being inaccurate. I think that satisfying people's curiosity is the most important thing I could be doing (and usually enjoy doing it). I am normally terse in my writing and would appreciate requests to verbosify.

I appreciate it if my grammar or style is corrected (in any of the languages I use here).

This profile is from a federated server and may be incomplete. Browse more on the original instance.

lynne, to random
@lynne@pars.ee avatar

Now I think about it, Telefunken is a bad name for a company that made vacuum tubes and microphones. You don't want your tubes or microphones to spark.

robryk,
@robryk@qoto.org avatar

@lynne except for electret ones :)

ZachWeinersmith, to random
@ZachWeinersmith@mastodon.social avatar

So, 10-year-old started learning how to convert things to scientific notation, and at first I was skeptical of what the point was, but it's surprisingly good for solidifying ideas about how to push exponents around.

robryk,
@robryk@qoto.org avatar

@ZachWeinersmith this reminds me of thinking how large a mole of buses would be

robryk, to random
@robryk@qoto.org avatar

Ignoring any correlations between general health and weight, I would naively think that #cancer risk would be proportional to weight (or rather, weight of the tissue in question): the chance of creating a mutation that is effective at creating a malignancy should be roughly constant per cell per unit of time, so the total rate of that happening should scale with number of cells.

Is there an obvious reason why this scaling is wrong, or is it not observable due to the health-weight correlation? (I've spent a few minutes trying to look it up, but found a mountain of experimental results correlating BMI with cancer risk only.)

attie, to random
@attie@chaos.social avatar

This is utterly wild... am I a little smooth-brained, or is this totally unrealistic?

  • 200 Mbps compressed to under 1 Mbps
  • Realtime, i.e: ~1ms latency or better
  • Encode and transmit in <10mW (yes, including radio)
  • Lossless
  • High-entropy input

... if you succeed, just email them your solution - no mention of any reward or Nobel Prize nomination.

https://content.neuralink.com/compression-challenge/README.html

robryk,
@robryk@qoto.org avatar

@cliffordheath @attie

This is also a reason why their request is likely simply impossible. I expect the signal to have some amount of white noise, and they ask for lossless compression, so they are asking for the noise to be reproduced exactly.

They have 10b samples and want more than 200x compression (presumably over linear PCM, which is the format of the files they published). This can only work if any white noise present itself takes less than 1/200 of the data rate, so if the white noise's amplitude is on the order of 2^-20 of their resolution (encodable in ~1/20 bit/sample).

(I speak of white noise only, because I'm assuming it's uncorrelated in different samples, both across electrodes and across time.)

robryk,
@robryk@qoto.org avatar

@codefolio @attie

They explicitly ask for lossless though. (To be fair, asking for lossy requires having a loss metric, which requires a good understanding of what's signal and what's noise.)

robryk,
@robryk@qoto.org avatar

@crschmidt @attie

This is data sampled from some sort of sensors. It will have some sort of white-ish noise added to it, because a.o. the sensors quantize and if you are close to the boundary between 8 and 9 the choice of what the sensor emits can get arbitrarily sensitive. They are asking for lossless compression, so they are asking for that noise to be reproduced. That sounds totally impossible in the data rate described.

robryk,
@robryk@qoto.org avatar

@cliffordheath @attie

Yeah, they could simply describe a relaxed comparison that would at least free implementations from having to reproduce quantization noise (e.g. pointwise difference between original and decompressed at most 1 everywhere). But if they wanted to ask people not to faithfully reproduce other kinds of noise, they would need to first mostly solve the problem by describing how to compare two signals for equality modulo all those kinds of noise.

robryk,
@robryk@qoto.org avatar

@dr2chase @crschmidt @attie

Or they were tired of opposing stupid ideas, so wanted to focus on opposing stupid ideas that have worse consequences.

mcc, to random
@mcc@mastodon.social avatar

The problem with udm14* is that Google Calculator is legitimately one of my favorite pieces of software (the natural language unit conversion is so good), and I expect udm14 is going to kill Google Calculator because that's the point

Maybe I should just make my own js calculator with builtin unit conversion.

  • See https://mastodon.online/ ; it's great, although since similar "give me the old version" flags on YouTube have sometimes stopped working without warning, I wonder how long it will last
robryk,
@robryk@qoto.org avatar

@whitequark @mcc

This made me start thinking how to add handling of logarithmic units to it :)

robryk,
@robryk@qoto.org avatar

@whitequark @mcc

And fractional powers.

robryk,
@robryk@qoto.org avatar

@whitequark @mcc

Eh, it does as badly as everything else on Grays and Sieverts (it will happily convert between one and other).

b0rk, to random
@b0rk@jvns.ca avatar

finally ready to announce that my git zine, “How Git Works", is coming out in ONE WEEK! on May 31!

it also comes with this (free!) cheat sheet which you can download and print out here: https://wizardzines.com/git-cheat-sheet.pdf

robryk,
@robryk@qoto.org avatar

@b0rk Out of curiosity, why does the "do a fastforward merge" tip not use --ff-only? (I would expect it to, because that makes the situation less confusing if an ff merge is impossible. But maybe brevity won out?)

BTW. I really like that you mention --force-with-lease over --force (especially that I keep forgetting the name of the flag for the former).

robryk,
@robryk@qoto.org avatar

@b0rk You might need to back the merge out though, if the merge was not an ff, but was trivial enough not to require your assistance.

mcc, to random
@mcc@mastodon.social avatar

We are in Programmer Hell

We have a ourlibrary.a file built in March

We can link ourlibrary.a into an application, it builds and the program runs

But if we build ourlibrary.a from source, the same untouched code and vcxprojes from march, it produces an ourlibrary.a that— when linked into the application— causes the final application to fail with a linker error that it can't find any of the OpenGL symbols.

Something changed on the build machine since March and we don't know what.

robryk,
@robryk@qoto.org avatar

@mcc

Where do you try to run it?

sarahjamielewis, to random
@sarahjamielewis@mastodon.social avatar

Software request: I'm looking for a tool I can use to manipulate nodes in a graph. Specifically I would like to be able to:

  • Add new nodes to the graph (not a tree)
  • Create multiple distinct edge relationships between nodes (bonus if the tool lets me formalize these edge types)
  • Have nodes contain notes, perhaps be typed
  • Export the graph to a reasonable (text) file format for external processing
  • Explicitly not an image editor or diagram tool.
  • Run on linux / be open source (flexible)
robryk,
@robryk@qoto.org avatar

@sarahjamielewis

Do you want to see the whole graph in one view, with each node having some (editable) position, or do you envision some other visual representation?

I'm asking because you mention thousands of nodes, and that seems like something that can be wieldy in single-sheet setup only if it's really sparse.

_thegeoff, to Cosmology
@_thegeoff@mastodon.social avatar

#Cosmology folk: the universe as-is exists because the very early stages had density variations, stuff clumped. That's fairly obvious, the odds of the universe being perfectly evenly distributed are basically impossible, only one way to do it (and, quantum, not even allowed?)
So what's the thinking on how unlikely our "unclumpiness" is? Compared to...I don't know, perfect homogeneity versus weirdly clumpy?

robryk,
@robryk@qoto.org avatar

@_thegeoff @ottaross

Clumpiness needs some notion of scale: at some scale, a big ball of water is extremely clumpy, because most of it is ~empty and there are some very heavy nuclei strewn around. At more coarser scale, it's very uniform.

(At sufficiently coarse scales ~everything becomes uniformish, but the coarseness of that scale depends on the thing and IMO there might be multiple changes back-and-forth below that.)

sgf, to random
@sgf@mastodon.xyz avatar

Random fun fact: They don't want you to think too hard while waiting for your PET scan in case it makes your brain glow.

(Some technical liberties may have been taken with this explanation.)

robryk,
@robryk@qoto.org avatar

@sgf

I never really understood why: signal strength of brain compared to everything else is not used diagnostically. I don't think PET is so close to the acceptable SNR boundary that the amount of "shiny glucose" this takes away from everywhere else matters (or am I wrong?). Or does this introduce variations within the brain that might be confusing?

Also, good luck getting some people not to think too hard :)

niconiconi, to random

"filing a bug against Windows 95: When you earned the cloaking device on level 58 [in Wing Commander III] or something, you couldn’t activate it. [..] The problem was that the hotkey [...] was Ctrl+C"

LMAO ​:blobcatlul:​

robryk,
@robryk@qoto.org avatar

@rq @niconiconi

Sadly one of the MS blog migrations got rid of all the comments :/

timorl, to random
@timorl@social.wuatek.is avatar

I’ve been struck by inspiration, but I cannot find the “rejects gender/collects gender for nefarious purposes” comic which I need for nefarious purposes, anyone has it by any chance?

robryk,
@robryk@qoto.org avatar

@timorl https://www.reddit.com/r/TheTransZone/comments/zo56jm/collects_gender_this_is_a_surprise_tool_that_will/ ?

(Though it's very likely not the original copy of it~)

quaap, to random
@quaap@toot.io avatar

As I walk through the valley of the shadow of death, I think: Wow Google Maps, you really fucked up this time

robryk,
@robryk@qoto.org avatar

@quaap

"The spectral wolf fears only fire. The Google Maps team can no longer help, but if you master the wolf, he will guide you. Godspeed."

whitequark, to random
@whitequark@mastodon.social avatar

for most of my life when i did play games i'd play shooters simply because it was something that i found that distracted me from overwhelming chronic pain, and i didn't think about it much if at all

so now that i've recently realized that you can, and should, outsmart and outplan the enemy, the experience completely changed for me

robryk,
@robryk@qoto.org avatar

@whitequark

You mean shooters where you play against people or against bots?

foone, to random
@foone@digipres.club avatar

I saw this voltmeter at the electronics flea market. Look at that massive probe! It looks like you need to check your back blast before using it.
Apparently it's for REALLY high voltages? Like, 3kV?

robryk,
@robryk@qoto.org avatar

@foone

What's the dial on the probe?

robryk,
@robryk@qoto.org avatar

@domi @foone

I expect that the probe is scaling the voltage down for the multimeter (this is what HV oscilloscope probes do).

glightly, to cycling
@glightly@mastodon.social avatar

I've thought about using the cargo quadricycle to take my propane tank to the hardware store for a refill but didn't do it because it felt hard to do safely.

That didn't worry this person, who has put the tank (about 1/3 the size I have) on a furniture dolly improvised into a trailer.

robryk,
@robryk@qoto.org avatar

@Suiseiseki @sohkamyung

I would guess that the main risk comes from blows to the valve (which enjoys a significant but incomplete protection from that collar).

robryk,
@robryk@qoto.org avatar

@Suiseiseki

I think you are right on limited consequences of a fire. I would expect though that an ignition source should be pretty easy to find in a car accident: the exhaust systems of all involved cars are likely got enough.

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