rnather @rnather@mathstodon.xyz

Pretty sure my gender is not computable in polynomial time. You could say I'm NB-complete.

#AdHackManifesto

1. Advertising shits in your head, it is a form of visual and psychological pollution.

2. Removing/Replacing/Defacing advertising is not vandalism, it is an act of tidying up that is both legally and morally defensible.

3. The Visual Realm is a Public Realm, it is part of the commons, it belongs to everyone, so nobody should be able to own it.

4. Outdoor Advertising can and should be banned, Sao Paulo did it in 2006, Grenoble followed suit in 2015.

it’s real important to give yourself credit. it’s really hard to do that in a lot of cases for so many reasons but sometimes you just need to stop and look at everything you’ve done, everything you’ve gone through, small things, huge things, things people know, things they don’t, & see that you’re here.

Differences between computer people and maths people:

Me: How would you write down a sequence of for-loops nested to arbitrary depth?

Computer people: Why would you want to do that? Look, this is what is known as an x-y problem, let me tell you instead what you should be asking...

Maths people: Ah, yes, tensor products have a universal mapping property over multilinear maps, so just pick some coordinates and write down the computation you want. It's all rather trivial.

off on a tangent: did you know that the clear stuff (vitrious humor? aqueous? we forget which) in your eyeballs can scintillate when struck by charged particles, and make your eyes act like little cosmic ray detectors?
retinas are sensitive - it only takes about four photons to activate a rod cell in near-total darkness - and astronauts have talked about seeing blue flashes with their eyes closed all the time while in space, especially in higher orbits.

Cunningham's Law: "The best way to get the right answer on the internet is not to ask a question; it's to post the wrong answer."

See that white tree there amongst the green ones? I'm not certain, but I think it's an albino.

Like animals, some tress are born as albinos, devoid of pigments due to a genetic mutation. Without photosynthetic pigments, a tree cannot harvest energy from sunlight and normally wouldn't survive. But in a rainforest, any tree will be nurtured by the rest of its community, sharing resources through their roots. Even a tree unable to give anything back.

Image credit: Paulo Whitaker/Reuters

Give someone a program, you frustrate them for a day; teach them how to program, you frustrate them for a lifetime. -- David Leinweber

PORTMANTDOME: TWO WORDS ENTER, ONE WORD LEAVES

https://www.reddit.com/r/toronto/comments/b7jr4u/saw_this_plaque_walking_along_crawford_gave_me_a/

Q: What's yellow, linear, normed, and complete? A: A Bananach space.

Twisting my own silk for attaching a slip to a piece of #stumpwork #embroidery. Somehow, nothing in my education remotely prepared me for this....

Was invited to a talk about machine learning fairness. Read it as machine learning 🧚‍♂️fairies🧚‍♂️. Now I'm so disappointed.

Picking a new computer:

1998: "Everything's twice as fast as it was last year! So much choice! So many options!"

2018: "OK, so which of these fucking things is the least broken?"

Package.
Chrishallbeckstore.Com

Feeling a bit pleased with some £watercolours I finished today, using photos from an excavation in Egypt during the Twenties.

There's a fine line between numerator and denominator (and it's called a 'vinculum').

Breaking news in the algorithmic/arithmetic world!

Integer multiplication in time O(n · log n). [1]

It means you can multiply two n-bits integer using roughly n log n operations. It's a *very* important problem because a lot of mathematical software rely on efficient integer multiplication.

It breaks the last best known algorithm [2] (Schönhage–Strassen), that was in O(n · log n · log log n)

[1] https://hal.archives-ouvertes.fr/hal-02070778/document
[2] https://en.wikipedia.org/wiki/Sch%C3%B6nhage%E2%80%93Strassen_algorithm

#maths #algorithm

Pixman:
struct pixman_box32
{
int32_t x1, y1, x2, y2;
};

Cairo:
typedef int32_t cairo_fixed_t;

typedef struct {
cairo_fixed_t x;
cairo_fixed_t y;
} cairo_point_t;

typedef struct {
cairo_point_t p1;
cairo_point_t p2;
} cairo_box_t;

Cairo:
pixman_box32_t *pbox;

pbox = pixman_region32_rectangles (&clip_region->rgn, &i);
_cairo_boxes_limit (&clear, (cairo_box_t *) pbox, i);

HOW THE FUCK CAN PEOPLE SLEEP AT NIGHT WITH THAT CAST