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mycl commented on Ask HN: What are you working on? (February 2025)    · Posted by u/david927
vector_spaces · 6 months ago
I'm interested in uniform approximation with generalized polynomials -- these are linear combinations from families of parametrized continuous functions over some domain that satisfy some technical conditions, but its also fine to think of them as sums of regular monomials like 1, x, x^2, ..., x^N. This problem has been well understood for real intervals (classical case) for a long time, but I'm interested in this problem where we're approximating functions over complex domains.

There is a theoretically stable algorithm for the classical problem called the Remez exchange algorithm, and an extension to complex domains due to P.T.P. Tang in his 1987 PhD thesis at Berkeley. Theoretically Remez and its complex extension are very stable, but unfortunately implementations my advisor and I are aware of seem to struggle with large degree polynomials, where large is bigger than say n=45 -- errors begin to explode.

In any case, independently of this I've been learning more of the nitty gritty details of deep learning for a project at work (I'm a SWE in my day job, the math is more moonlighting), so to ground my efforts there I've been exploring deep learning approaches to this problem of complex uniform approximation, implementing results from various papers and tweaking things for my use case, and coming up with questions. That's much of what I'm thinking about this week!

Also, I'll be having a half-day long ADHD evaluation session on Friday -- so a bit apprehensive about that.

mycl · 6 months ago
You say the math is more moonlighting, but you have a supervisor. Are you enrolled for a part-time degree while you work as a SWE?
mycl commented on Ask HN: Most interesting, mildly impractical, well-written books on software?    · Posted by u/eatonphil
mycl · 4 years ago
The Art of Prolog is now open access: https://mitpress.mit.edu/books/art-prolog-second-edition

You could think of it as "SICP for Prolog".

mycl commented on Using a Piece of Paper as a Display Terminal – Ed vs. Vim   blog.robertelder.org/pape... · Posted by u/rhabarba
saagarjha · 5 years ago
I am curious if anyone uses ed as their editor of choice these days, assuming an actual screen and such of course. If so, why? Muscle memory?

Has anyone come up with an ed with the advantages of a modern screen, so it shows the full file on the side but you can still run ed commands on it?

Edit: I should have expected getting "vi" as an answer, although I can't fault all the commenters below :P I was thinking of something a little less different, like literally just a command prompt on the bottom and a pane above centered on the line you just operated on.

mycl · 5 years ago
As to your second question: Yes, Bill Joy did that in 1976 when he added a visual mode to his line editor ex that was itself based on ed. The mode was called vi (for "visual") and updated the screen as you typed ex commands preceded by a colon. All vi descendants have this feature, including Vim. :-)
mycl commented on Escaping strings in Bash using !:q   til.simonwillison.net/til... · Posted by u/goranmoomin
twic · 5 years ago
Lifted directly from sed, one of Perl's inspirations:

  s/replace #/with $/
  s#replace /#with _#

mycl · 5 years ago
I think it was in ed already. The POSIX ed spec says: "Any character other than <space> or <newline> can be used instead of a slash to delimit the RE and the replacement."
mycl commented on Mathematicians should stop naming things after each other   nautil.us/issue/89/the-da... · Posted by u/abnry
aaron-santos · 5 years ago
The lack of eponymous names used in category theory, for example, do nothing to aid in learning it. The term functor is no more descriptive than Carnap mapping.
mycl · 5 years ago
The Yoneda Lemma is really some kind of "fundamental theorem" of elementary category theory. Then there are Freyd's Adjoint Functor Theorem, Kan extensions and probably others I'm forgetting...
mycl commented on The Looming Bank Collapse   theatlantic.com/magazine/... · Posted by u/sajid
dia80 · 5 years ago
Meh, the article doesn't mention recovery rates. If a loan defaults it's not usual you are getting 0 back. Typically 30-40% is the assumed rate. That means if all the loans default then the top 30% of tranches shouldn't take a loss.

So now consider, most of the underlying loans have to default and the recovery rate has to be below battle tested assumptions before the top tiers get risky. This is very very unlikely to happen given the Fed and the US Govt. have done so much and are committed to do more to stave off a severe depression / recession. It's more like people were killing it buying the safer parts at distressed prices as over leveraged funds shed them on the back of margin calls in March.

mycl · 5 years ago
It says this:

> We already know that a significant majority of the loans in CLOs have weak covenants that offer investors only minimal legal protection; in industry parlance, they are “cov lite.” The holders of leveraged loans will thus be fortunate to get pennies on the dollar as companies default—nothing close to the 70 cents that has been standard in the past.

mycl commented on Interesting Programming Languages   btbytes.com/pl.html... · Posted by u/andrenth
makapuf · 6 years ago
Bidirectional implies bijections, for isomorphism you'll need a morphism, a function that preserves/transposes some kind of structure or internal composition law (addition, multiplication,...)
mycl · 6 years ago
Interestingly, from the point of view of category theory, an isomorphism in a category is just a morphism with a two-sided inverse. A bijection is then just an isomorphism in the category of sets.
mycl commented on List of Cognitive Biases   en.wikipedia.org/wiki/Lis... · Posted by u/plibither8
SubiculumCode · 6 years ago
Some of which may be replicated.

I'd be tempted to down-vote myself for snarky trolling except that I work in the field of psychological research, and perhaps it is my bias, but many of the cognitive biases that came from social-psychology research do not stand up to scrutiny, too frequently resulting from bad statistical practice...at least two decades ago.

mycl · 6 years ago
Can you expand on that? My impression is that Kahneman and Tversky "proved" that human cognition is not Bayesian and now much of cognitive psychology is turning around and saying, no, they didn't, and it is. As a layperson, I don't know whom to believe.
mycl commented on The Birth of Prolog (1992) [pdf]   web.stanford.edu/class/li... · Posted by u/mindcrime
Stwerner · 7 years ago
I've noticed prolog being mentioned here and a bunch of other places, but haven't really found any good introductory books on the language.

Does anyone have any recommendations?

mycl · 7 years ago
Peter Flach's "Simply Logical: Intelligent Reasoning by Example" also deserves to be mentioned as a wonderful introduction to Prolog and computational logic in general. It's available as a PDF from the author (http://people.cs.bris.ac.uk/~flach/SimplyLogical.html) and also in an interactive version where the examples can be run in-browser, using SWISH: https://book.simply-logical.space/
mycl commented on The Birth of Prolog (1992) [pdf]   web.stanford.edu/class/li... · Posted by u/mindcrime
nyankosensei · 7 years ago
...and it’s Open Access, i.e. free download.
mycl · 7 years ago
Holy Cow, I had no idea. I have a physical copy, but now I can suggest this to everyone.

u/mycl

KarmaCake day45April 13, 2016View Original