keithalewis's comments

On: Mathematical Thinking Isn't What You Think It Is

[keithalewis]

I work hard to be lazy.

On: A binary tree of all Pythagorean triples

[keithalewis]

There are Pythagorean triples (a, b, c) for which there do not exist integers m, n with a = m^2 - n^2, b = 2mn, c = m^2 + n^2.

[tromp → keithalewis]

But all such triples are non-primitive. I.e. they are of the form (ka, kb, kc) with k>1. So all Pythagorean triples can be generated as a scaled primitive triple (a,b,c) that is generated by Euclid's formula from m,n.

[FredrikMeyer → keithalewis]

Learned something new today. For other interested: https://en.wikipedia.org/wiki/Pythagorean_triple#Generating_...

On: Differential Dataflow for the Masses

[keithalewis]

This seems to make the mistake of identifying a vector with a stream.

[rebanevapustus → keithalewis]

In this implementation streams are not vectors nor lists. They are ordered hash maps.

[keithalewis → rebanevapustus]

Just pointing out what the theoretical documentation says. A stream should have operations for empty, current, and next. You don't want implementation details leaking into the abstract model.

On: Launch HN: Codebuff (YC F24) – CLI tool that write...

[keithalewis]

HN spamtroturfing one of their own startups? I'm shocked, shocked!

On: 'I grew up with it': readers on the enduring appea...

[keithalewis]

I wrote something to make it simple to embed C++ in Excel. It is useful for pushing business logic into platform independent code that can be integrated into back end production systems. One bonus is the original spreadsheet has unit tests vetted by the business users. https://github.com/xlladdins/xll

On: 'I grew up with it': readers on the enduring appea...

[keithalewis]

Control-backtick toggles formulas. No need for VB(A).

[analog31 → keithalewis]

Ah, I didn't know that. So I tried it.

It does display formulas, but by hiding the values. What my macro does is allow the formula to be displayed permanently in its own column.

Granted I'm one user out of many, and have switched to programming for any kind of quantitative work. but I'm still quite supportive of Excel.

[keithalewis → analog31]

Do you realize it toggles data and formula display? That ought to be fine for anyone with more short term memory than a gnat.

On: Show HN: Finstruments - Financial instrument libra...

[keithalewis]

Do you have an example of a convertible bond?

[kyleloomis → keithalewis]

Not yet, I will work to add this soon.

On: Axiomatics: Mathematical thought and high modernis...

[keithalewis]

Try composing two distributions.

[practal → keithalewis]

Try composing f : A -> B with g : A -> B, for A ≠ B. Still, f and g are functions. So, what exactly is your point?

[keithalewis → practal]

What is a delta function at a composed with a delta function at b <> a?

On: Show HN: Nextread.ai – AI-powered book recommendat...

[keithalewis]

Attention Everyone!!! We have just found our killer AI app!!! Just imagine, you no longer need to talk to friends, family, or waste time on social networks to get a list of books you are never going to read!!!

I can't wait to start buying tulip bulbs for pennies on the dollar.

On: How to make Product give a shit about your archite...

[keithalewis]

Doctor, it hurts when I do that.