Hacker News: jlrubin

New comment by jlrubin in "Jeffgeerling.com has been migrated to Hugo"

jlrubin — Mon, 05 Jan 2026 01:32:09 +0000

one thing i've found, is that i've regretted not blogging more via PDFs.

This is because Google Scholar treats PDFs as first class citizen, so your Important blog posts can get added to academia.

maybe a plugin can solve this particular gripe...

New comment by jlrubin in "Rust in the kernel is no longer experimental"

jlrubin — Wed, 10 Dec 2025 15:45:26 +0000

@dang title has been changed to "The (successful) end of the kernel Rust experiment", since there were complaints in the articles comments from the committee members that that was a sensationalization of what actually happened.

New comment by jlrubin in "Data Structure for Dynamic Discrete Probability Distributions"

jlrubin — Mon, 21 Apr 2025 19:16:29 +0000

Options like std::discrete_distribution don't allow updates, in Rust e.g. https://docs.rs/rand_distr/latest/rand_distr/weighted/struct... allows updates but sampling is O(log n) and updating is also O(log n).

This neat data structure has a great set of tradeoffs.

Data Structure for Dynamic Discrete Probability Distributions

jlrubin — Mon, 21 Apr 2025 19:16:29 +0000

Article URL: https://github.com/Daniel-Allendorf/proposal-array

Comments URL: https://news.ycombinator.com/item?id=43755429

Points: 1

# Comments: 1

New comment by jlrubin in "New Proof Settles Decades-Old Bet About Connected Networks"

jlrubin — Sun, 20 Apr 2025 22:19:52 +0000

> The fraction turned out to be approximately 69%, making the graphs neither common nor rare.

The wording kinda bothers me... Either 31% or 69% is exceedingly common.

Rare would be asymptotically few, or constant but smaller than e.g. 1 in 2^256.

I guess the article covers it's working definition of common, ever so briefly:

> that if you randomly select a graph from a large bucket of possibilities, you can practically guarantee it to be an optimal expander.

So it's not a reliable property, either way.

New comment by jlrubin in "Most of Europe is glowing pink under the aurora"

jlrubin — Sat, 11 May 2024 17:15:18 +0000

i have the unique experience of being in a plane over the Bering sea a few hours ago. https://twitter.com/JeremyRubin/status/1789273537179426922

i was going nuts in my seat and seemed to be the only one on the plane aware of what was going on.

New comment by jlrubin in "Money market funds swell by over $273B as investors pull deposits from banks"

jlrubin — Sun, 26 Mar 2023 18:03:21 +0000

wouldn't those be a different category & thus get unique coverage?

New comment by jlrubin in "It’s not Tourette’s but a new type of mass sociogenic illness"

jlrubin — Tue, 06 Dec 2022 19:58:47 +0000

anecdotally, i had a professor (if you're reading this, hi) who would wink in conversation at exactly the right point to add a little "isn't the world a funny place" comedy to whatever he was saying... wasn't clear if intentional or a tic for when he thought he had said something clever. I noticed that habit to have transferred to me for a while after, though I think now it's faded.

New comment by jlrubin in "White House deletes tweet after Twitter adds 'context' note"

jlrubin — Fri, 04 Nov 2022 22:49:15 +0000

money = money(t)

inflation = d money / dt

rate of increase of inflation = d^2 money / dt^2

rate of change in rate of increase of inflation = d^3 money / dt^3

rate of increase of inflation was decreasing = sign(d^3 money / dt^3)

New comment by jlrubin in "Stripe laying off around 14% of workforce"

jlrubin — Thu, 03 Nov 2022 18:13:43 +0000

that'd cause an org wide panic, and you might lose key personel in your actually profitable business units. cutting costs at this scale is not just reducing employees, it's getting rid of employees who are working in areas you need to cut. the secrecy lets management retain control.

New comment by jlrubin in "Python’s “type hints” are a bit of a disappointment to me"

jlrubin — Fri, 22 Apr 2022 05:54:53 +0000

fwiw i was able to successfully port this complex project into rust's type system.

New comment by jlrubin in "Python’s “type hints” are a bit of a disappointment to me"

jlrubin — Fri, 22 Apr 2022 05:54:12 +0000

my experience with python's optional type system was that the simple stuff works very well, but when you try to go down a type rabbit hole for more advanced stuff involving generics it becomes really unworkable, inconsistent, and hard to dig yourself out of.

but for little things, like just function signatures, it's great!

New comment by jlrubin in "How much Rust in Firefox?"

jlrubin — Sun, 20 Mar 2022 17:32:34 +0000

note that it is measured in SLOC.

You can do in 500 lines of rust what might take 5000 lines of C.

I would be interested to see this as a stack chart showing overall LoC.

New comment by jlrubin in "Eric Schmidt plans to give A.I. researchers $125M"

jlrubin — Thu, 17 Feb 2022 23:43:20 +0000

The free market is usually better at allocating resources than the government.

Plus, the government already has much more than $125M it could use to fund AI research, why do we need to take away Schmidt's funds to do so?

New comment by jlrubin in "The case for and against analogies"

jlrubin — Fri, 04 Feb 2022 19:44:46 +0000

like them or not, analogies are one of the pillars of the American legal system. Being able to reason about them and create them (usually with motivated reasoning) is a highly valuable skill.

For those unaware, in a legal case where there is no precedant (something us technologists encounter often), you make the case that what you are doing is just like what X had done, and should be treated in kind.

New comment by jlrubin in "Idris 2: Quantitative Type Theory in Practice"

jlrubin — Mon, 24 Jan 2022 01:24:41 +0000

you got it flipped. Dependendent types enable you to do things like "takes a nonempty list" and "returns a nonempty list of greater size".

Linear types lets you do things like "this data can only be written to a file once".

New comment by jlrubin in "Saving a Third of Our Memory by Re-Ordering Go Struct Fields (2020)"

jlrubin — Tue, 11 Jan 2022 19:17:39 +0000

scottlamb seemed to be implying it's not worth being able to since it's an uncommon use case, so I was explaining why even if it's uncommon it's must-have.

New comment by jlrubin in "In Search of an Understandable Consensus Algorithm (2014) [pdf]"

jlrubin — Tue, 11 Jan 2022 05:15:52 +0000

Hi back atcha!

I took 6.824 under Paxos (I think we took it at the same time maybe? not sure if you were TA at that point) and then helped a friend when it switched to raft and good lord that seemed to be a worse for them.

New comment by jlrubin in "Saving a Third of Our Memory by Re-Ordering Go Struct Fields (2020)"

jlrubin — Tue, 11 Jan 2022 05:14:25 +0000

my point is that these are the fat tail + survivor bias of cases where you do actually care about performance to this degree, so it probably is actually more common in practice when you're looking into it.

even though precise control is the exception, if you can't do it, you can't use your language in a lot of critical contexts (and end up linking C, Zig, Rust, etc).

New comment by jlrubin in "Saving a Third of Our Memory by Re-Ordering Go Struct Fields (2020)"

jlrubin — Mon, 10 Jan 2022 06:55:58 +0000

it's very likely that it's one of the cases that when reducing cache misses does really matter it's very different from using as little space as possible, and the degree to which it matter dwarfs the degree to which it's not a frequent concern (i.e. fat tail).

for example, if I have a struct that contains a bunch of atomic fields, I may actually want to control the layout to ensure they are far apart (even inserting padding) to prevent e.g. false sharing https://en.wikipedia.org/wiki/False_sharing.