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duetosymmetryon Lisp implemented in Rust macros

Greenspun's tenth rule strikes again! https://en.wikipedia.org/wiki/Greenspun%27s_tenth_rule

duetosymmetryon Show HN: Interactive polynomial roots toy

Hi, yes, it's open source. My web site's github repo is at https://github.com/duetosymmetry/web-site/tree/customization . The JS for controlling the web toy is at https://github.com/duetosymmetry/web-site/blob/customization... . This relies on a modified version of Polynomial.js which I will hopefully get accepted upstream, but for now it's just on my fork at https://github.com/duetosymmetry/Polynomial.js/tree/Aberth (though this is also behind my local repo).

duetosymmetryon Show HN: Interactive polynomial roots toy

I wanted to keep the UI from getting too busy, which is why I limited the degree to 7. But if somebody really wants to play with higher-degree polynomials, I'm not going to stop them!

duetosymmetryon Why is the Quintic Unsolvable?

I was just pondering about this. I imagine that moving a coefficient a small amount (and so long as the roots are not too close) that Newton-Raphson, initialized with a previously-known root, would converge very quickly to the new root while preserving the order.

If there truly are roots of multiplicity >= 2, then preserving the order of the multiple roots doesn't matter. Another issue is that Newton-Raphson might fail if the roots are too close.

duetosymmetryon Astronomers may soon have the first picture of a black hole

That's the one in our galaxy, and the other target—in the galaxy M87—is around 5 billion times the mass of the sun!

duetosymmetryon Astronomers may soon have the first picture of a black hole

I believe every radio telescope has their own reference clock that lives at the site. The EHT team is not responsible for schlepping these clocks around. There are other reasons besides VLBI to have really good timing at the site—for example, pulsar timing.

duetosymmetryon How to Swap two numbers without temp variable in Java

> fixed-length binary strings are a group where the operation is xor (or '^') and inv(x) = x

Most people would call this group (Z/2Z)^n, i.e. n copies of Z/2Z under addition. Similarly, for "matrix addition" you could say Z^(mn) or R^(mn) for matrices with dimension mxn with elements Z or R (or whatever you are filling your matrices with). Your only non-abelian example is matrix multiplication, i.e. GL(n,R), general linear transformations of dimension n over R. It may or may not be interesting that this is mainly focused on abelian groups.