Hacker News: davidgrenier

New comment by davidgrenier in "Finding all regex matches has always been O(n²)"

davidgrenier — Tue, 24 Mar 2026 11:17:04 +0000

I wonder how gracefully redgrep handles this. This tool hasn't been talked about since the year of its release. If I recall correctly, it doesn't handle some obstruse regexes the way conventional tools do however.

https://github.com/google/redgrep

New comment by davidgrenier in "Trump's attacks on universities get darker, with shadows reaching our shores"

davidgrenier — Sat, 29 Mar 2025 11:46:19 +0000

There's only one "other side" in this, it's the American people.

New comment by davidgrenier in "Canon wants us to pay for using our own camera as a webcam"

davidgrenier — Fri, 17 Jan 2025 11:58:37 +0000

v4l2-ctl on linux allows me to change such settings on a global level, maybe that might work if a version can be found on his OS.

New comment by davidgrenier in "It's time to abandon the cargo cult metaphor"

davidgrenier — Mon, 13 Jan 2025 12:04:08 +0000

I think the author is generous in granting that Caro-Cult programming works.

New comment by davidgrenier in "“A Course of Pure Mathematics” – G. H. Hardy (1921) [pdf]"

davidgrenier — Tue, 31 Dec 2024 11:54:30 +0000

I haven't looked at Hardy's but the presentation in Spivak is also Dedekind cuts. Perhaps Hardy uses a different approach and OP misnamed it? Rudin's chapter 1 annex also use Dedekind's cuts.

New comment by davidgrenier in "“A Course of Pure Mathematics” – G. H. Hardy (1921) [pdf]"

davidgrenier — Tue, 31 Dec 2024 11:48:00 +0000

Where we define the real numbers as the least upper bounds of special sets. There is a bijection between these sets and the set of real numbers which we commonly think of and that bijection is the least upper bound of such sets.

New comment by davidgrenier in "Formal methods: Just good engineering practice?"

davidgrenier — Mon, 24 Jun 2024 11:19:47 +0000

Your very last example kinda supports the thesis up there, considering how it's been going.

New comment by davidgrenier in "Researchers have found a faster way to do integer linear programming"

davidgrenier — Tue, 30 Jan 2024 12:13:46 +0000

Correct me if I'm wrong but (log n)^O(n) sounds like atrocious complexity?

New comment by davidgrenier in "Researchers have found a faster way to do integer linear programming"

davidgrenier — Tue, 30 Jan 2024 12:07:30 +0000

LP or ILP? There is a significant difference since for non-discrete problem Linear Programming is shockingly efficient and in no way can be considered a brute force technique.

edit: What would be a technique you consider non-brute force in discrete problems?

New comment by davidgrenier in "Conway's Game of Life is omniperiodic"

davidgrenier — Fri, 08 Dec 2023 12:18:07 +0000

I was speculating two oscillators with periods p and q could be composed (as long as there was no way for them to interact) to create an oscillator of period p*q/gcd(p,q) but wondering why large primes wouldn't be a problem.

I guess this is my answer.

New comment by davidgrenier in "Mathematical proof is a social compact"

davidgrenier — Thu, 31 Aug 2023 17:51:03 +0000

I think his argument was restricted to a human-produced mathematical result being ported to a Lean program where one would be just as likely to commit a mistake. However I disagree as well, I recall the difficulty of expressing what I wanted to Coq being a barrier to expressing it incorrectly.

New comment by davidgrenier in "Mathematical proof is a social compact"

davidgrenier — Thu, 31 Aug 2023 17:31:47 +0000

Good teacher, his Number Theory book felt really good though I have no comparable in Number Theory. I must say Number Theory and Combinatorics are the most difficult topics I got acquainted with in undergrad.

New comment by davidgrenier in "Ask HN: What is the best desk chair for small spaces?"

davidgrenier — Sun, 06 Aug 2023 13:29:04 +0000

Bouty makes excellent chair. Looking at their website I'm thinking Arista/Kadera/Fira. The model of chair I have doesn't seem front page but it is the Sity 9002.

The piston gave after 10+ years of service. Contacted them, warranty is for life, they had someone show up and replace it for free.

New comment by davidgrenier in "F# RISC-V Instruction Set formal specification"

davidgrenier — Sat, 29 Jul 2023 10:44:27 +0000

It isn't though: https://github.com/mrLSD/riscv-fs/blob/fa039b123ded9fa0c05d0...

New comment by davidgrenier in "F# RISC-V Instruction Set formal specification"

davidgrenier — Sat, 29 Jul 2023 10:40:15 +0000

I think this qualifies?

https://en.wikipedia.org/wiki/MMIX#Simulators_and_assembler

New comment by davidgrenier in "F# RISC-V Instruction Set formal specification"

davidgrenier — Sat, 29 Jul 2023 10:37:35 +0000

My understanding of this is that it is an emulator that is meant to be very clear to read.

New comment by davidgrenier in "Mozilla should call for the removal of Google from W3C because of WEI"

davidgrenier — Fri, 28 Jul 2023 10:48:59 +0000

Someone mentionned in the Mastodon thread that they have an Android phone with nothing-from-google on it. I speculate his installation is even more responsive than whatever default the product came with and I'd like to do that.

I have a terrible Vankyo Z1 table that is very slow. Where do I start?

New comment by davidgrenier in "Threads and Goroutines"

davidgrenier — Tue, 25 Jul 2023 12:04:51 +0000

Note that lightweight threads (even in CSP style concurrency model) can be even lighter and faster. F#'s Hopac library seems to meet such expectations with this simple program:

   #r "nuget:hopac"

   open Hopac
   open Hopac.Infixes
   open Hopac.Extensions

   seq{1..1000000}
   |> Seq.Con.iterJobIgnore (fun _ -> timeOutMillis 1000)
   |> run

Runs in 1.824s real, 17.635s user and 0.088s system time in under 186000KB, hence less around 200 bytes per thread.

10M threads sleeping 10 seconds taxes this machine to:

22s real, 4m user, 0.506s system @ 140 bytes/thread.

New comment by davidgrenier in "Python consumes 38x more energy than Java"

davidgrenier — Thu, 13 Jul 2023 11:01:43 +0000

But isn't what makes numpy efficient written in C?

New comment by davidgrenier in "People running Windows 11, are you all running Sluggish Incarnate?"

davidgrenier — Mon, 03 Jul 2023 13:18:40 +0000

Will double check both systems I have access to, thanks.