Science Memes

13911 readers

1724 users here now

Welcome to c/science_memes @ Mander.xyz!

A place for majestic STEMLORD peacocking, as well as memes about the realities of working in a lab.

Rules

Don't throw mud. Behave like an intellectual and remember the human.
Keep it rooted (on topic).
No spam.
Infographics welcome, get schooled.

This is a science community. We use the Dawkins definition of meme.

Research Committee

[email protected]

Other Mander Communities

Science and Research

Biology and Life Sciences

Physical Sciences

Humanities and Social Sciences

Practical and Applied Sciences

Memes

Miscellaneous

founded 2 years ago

MODERATORS

[email protected]

595

identity theft (lemmy.dbzer0.com)

submitted 2 weeks ago by [email protected] to c/[email protected]

20 comments fedilink hide all child comments

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 38 points 2 weeks ago* (last edited 2 weeks ago) (11 children)

Could one of you scholars please explain the joke for us smoothbrains who don't get it? All I see is a boolean matrix, and I'm not even sure that is correct.

[–] [email protected] 13 points 2 weeks ago* (last edited 2 weeks ago) (5 children)

That matrix of zeros with one in diagonal is called the matrix of identity.
It is famous because when doing multiplication on matrix or vector, it acts likes 1 on "normal" number:
x times 1 is x anyMatrix times Identity is anyMatrix.

[–] [email protected] 5 points 2 weeks ago (2 children)

Wouldn't you need to put anyMatrix first, since matrix multiplication isn't commutative?

[–] [email protected] 3 points 2 weeks ago (1 children)

You are right. I will correct it.

[–] [email protected] 1 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

No I just tried it and I was wrong, it seems like it doesn't matter for the ID matrix specifically

[–] [email protected] 1 points 2 weeks ago

I need to freshen up on my linear algebra. I don't remember on which sense it goes but I think if you swap the factors, you'll have to you transpose the matrix x to keep the same result.

[–] [email protected] 1 points 2 weeks ago

Huh? Identity times anyMatrix is also anyMatrix. The matrix just has to have the right dimensions

load more comments (2 replies)

load more comments (7 replies)