HNHacker News
TopNewBestAskShowJobs

mpreda

437 karma · joined September 22, 2016

submissionscomments
mpreda··on Ask HN: What are you reading?
Looked over the lists, and there is one that was not mentioned yet:

1. "Lord of Light" by Roger Zelazny

mpreda··on Hunting Million-Digit Primes from My Loft
The largest known prime could be considered a universal scientific benchmark.

It is also a concise statement that is trivial to verify.

(by "trivial" meaning much much easier to verify than to discover in the first place)

mpreda··on Ending respiratory infections
> I'm much more keen on never getting sick than prepping for Mars.

Never getting sick is an enabler to reaching the goal. And the goal is..?

mpreda··on How many of the 170k English words do you know?
> and hippo, from the latin root, I knew was not as obvious as the animal, but probably something like "large" (clue: the Hippodrome)

Well.. Hippos is greek for horse, and Hippopotamus is a "river horse". Same for Hippodrome, a course for horses. And in latin, hypo means small (and not large), as seen in e.g. hypoglycemia.

mpreda··on The Causes of Long Covid
Water fast is when the only intake is water (plus electrolites and vitamines). Basically "eat nothing".
mpreda··on Spanish archaeologists discover trove of ancient shipwrecks in Bay of Gibraltar
Another solution: train wild dolphins to recognize the goal (e.g. sunken ships), do the scan for you, and receive some compensation in exchange for the work they do (tasty food? play balls?). Should check the depth range of dolphins.
mpreda··on First G-SHOCK with a heart rate monitor, also featuring Smartphone Link
My ideal watch also has: mobile voice & data connection (via eSim), speaker and microphone, camera.

Those in addition to what it already has: 1 month battery life, HR and SpO2 tracking, flashlight.

Also, blood glocose and BHB monitoring would be nice.

And I didn't mention the software..

mpreda··on Peptides: where to begin?
Given that many people experiment on themselves anyway, I feel it's a pity and a loss for science that the outcomes of those self-experiments are not collected and aggregated.

The article itself raises the issue of "lack of clinical data", given that these substances are relativelly new. But the lack of data may originate from a certain stiffness, or lack of accessibility and high cost of clinical trials. An alternative source of information are these people who self-experiment, but unfortunatelly this information is mostly lost instead of being captured.

How could this proposal work in practice? clearly the data would be noisy, contain some false reporting, biased, subjective etc. But statistical processing of a large number of reports (coming from hudreds of thousands or millions of self-reporting subjects) may still extract relevant scientific information; that we're dropping on the floor right now.

An example: I'm experimenting with a radical diet. I keep observations for myself, but they're not shared with anybody and don't contribute to science.

What the altervative would be: I would enroll on a web page, where I would describe the experiment I plan to do before I start it. I would be get a code for a blood/urine work for the "before" state, with the agreement that the results, anonimized, are shared with the platform. Weekly I would report on the platform observations, such as: got sick in this particular way, wheight variations, sleep eval, or any other changes.

At the end, or periodically I would get new free blood/urine work with the results shared.

Research institutes and pharma would get access to the data, to aggregate and denoise as they can to extract the latent information.

mpreda··on Man wearing metallic necklace dies after being sucked into MRI machine
Not to mention that "gauss" sounds deadlier than "tesla" to begin with. Talking about choosing the right units.
mpreda··on Photon transport through the entire adult human head
In the nose as well.
mpreda··on US Administration announces 34% tariffs on China, 20% on EU
> They want to repudiate foreign held debt, or devalue it, by revaluation of the USD

I don't understand, who's holding that "foreign held debt"? foreign countries I suppose, so which countries do you have in mind?

For one, it's not China, which holds a large amount of US treasury bonds (so basically, China is a lender of USD). So the revaluation of USD would work great for China: one, the value of the China-held USD bonds increases, and second, the price of Chinese exports decreases in USD terms.

So help me understand, what's the plan with the revaluation of USD?

mpreda··on US Administration announces 34% tariffs on China, 20% on EU
> arabic numerals

Soon to be "Numerals of America"

mpreda··on It doesn't cost much to improve someone's life
But the US is efficiently disentangling itself from the entire rest of the world as we speak; so that argument may not hold anymore in the near future.
mpreda··on It doesn't cost much to improve someone's life
Indeed, federations splitting apart -- that's what happens in tough times.
mpreda··on STEPS Toward the Reinvention of Programming (2012) [pdf]
It's clear that alphabetical order is open to manipulation. Down that path and everybody in the scientific career will be named A.A.
mpreda··on Global sales of combustion engine cars have peaked
> Economic growth and population growth will likely keep that going up.

What population growth?

mpreda··on Zelensky leaves White House after angry meeting
The democratic system of checks-and-balances of USA needs to act to contain the Trump individual. After all the current USA government system is not a dictature and thus Trump is not supposed to have dictatorial powers.
mpreda··on Zelensky leaves White House after angry meeting
Impeach Trump.
mpreda··on How do modern compilers choose which variables to put in registers?
I second this.

It's nice to wish for the optimizer to do the [almost] perfect job, but sometimes that never arrives. Consider for example the case of AMD GPU ISA (GCN) generated by LLVM: it's been so far from optimal for so long, that one can lose hope that'll ever happen; and wish for a simple solution that works in the meantime.

mpreda··on Nvidia's RTX 5090 power connectors are melting
But I want fewer cables, not more.
mpreda··on Nvidia's RTX 5090 power connectors are melting
Now I must use lots of rather thick cables in my desktop (because I run GPUs).

Imagine that the GPU would instead suck up all the power it needs through the PCIe connector, without all those pesky cables. (right now PCIe can provied 75W at 12V, i.e. 6.25A; that same current would provide 300W at 48V).

mpreda··on Nvidia's RTX 5090 power connectors are melting
The voltage step-down is already in place, from 12V to whatever 1V or 0.8V is needed. Doing the same thing starting from 48V instead of 12V does not change anything fundamentally, I guess.
mpreda··on Nvidia's RTX 5090 power connectors are melting
Step the GPU voltage up to 48V. (anyway you make a new connector that's not compatible with existing PSUs. Why not actually fix a problem at the same time, once and for all! [48V should be enough for anybody, right?])
mpreda··on Don't "optimize" conditional moves in shaders with mix()+step()
Exactly. Consider this example:

  a = f(z);
  b = g(z);
  v = x > y ? a : b;
Assuming computing the two function calls f() and g() is relativelly expensive, it becomes a trade-off whether to emit conditional code or to compute both followed by a select. So it's not a simple choice, and the decision is made by the compiler.
mpreda··on Don't make fun of renowned author Dan Brown (2013)
This was no nice! had fun reading it.

Also learned the meaning of the conspicuous word pulchritudinous, which in the default Oxford languages dictionary Google uses [1] comes up with "Dan gazed admiringly at the pulchritudinous brunette" as usage example.

[1] https://www.google.com/search?q=pulchritudinous

mpreda··on Boosting Computational Fluid Dynamics Performance with AMD MI300X
And the splitting into CDNA and RDNA comes from the same direction: market segmentation, to allow much higher prices for the CDNA data-center GPUs, while keeping the gamer-focused RDNA GPUs affordable for mere mortals. Of coures this backfires by making the powerful GPUs not available for mostly anybody anymore to experiment on.

For example this blog post, about how great MI300X is. Really, what do I care -- I'm not a billionaire.

mpreda··on Boosting Computational Fluid Dynamics Performance with AMD MI300X
It seems AMD has to choose between monetizing the GPUs right now by selling them at the maximum effective price, or forgoing that gain and selling the GPUs at cost and increasing GPU market share in the future. The choice between short-term gain and long-term gain.
mpreda··on China's Bad, No Good Trillion-Dollar Trade Surplus
What is not explained in the article is how China is "weakening the value of its currency".

The answer to that question may offer a new insight on the situation, and help decide whether it's good/bad and for whom.

As I understand, weakening one's currency (in real terms) is not an easy thing to do. As an example, in the case of the Greece economic crysis mentioned in the article, Germany was considered as having benefited from the common currency (Euro, shared among others with Greece) to maintain a stable currency while sustaining a high positive trade balance.

What I suspect is happening is that China is buying US treasury bonds (exchanging Yuan for USD in the process), thus supporting the value of the USD.

mpreda··on Making AMD GPUs competitive for LLM inference (2023)
> I have 7 NVidia 4090s under my desk

I have 6 Radeon Pro VII under my desk (in a single system BTW), and they run hard for weeks until I choose to reboot e.g. for Linux kernel updates.

I bought them "new old stock" for $300 apiece. So that's $1800 for all six.

mpreda··on Show HN: Physically accurate black hole simulation using your iPhone camera
Like some intensive cash-generating activities: drug dealing, weapon traficking, stealing, and money printing. Value at its best.
Page 1 of 6Next →