this post was submitted on 15 Mar 2025
565 points (98.1% liked)
Science Memes
13374 readers
2139 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
Other Mander Communities
Science and Research
Biology and Life Sciences
- !abiogenesis@mander.xyz
- !animal-behavior@mander.xyz
- !anthropology@mander.xyz
- !arachnology@mander.xyz
- !balconygardening@slrpnk.net
- !biodiversity@mander.xyz
- !biology@mander.xyz
- !biophysics@mander.xyz
- !botany@mander.xyz
- !ecology@mander.xyz
- !entomology@mander.xyz
- !fermentation@mander.xyz
- !herpetology@mander.xyz
- !houseplants@mander.xyz
- !medicine@mander.xyz
- !microscopy@mander.xyz
- !mycology@mander.xyz
- !nudibranchs@mander.xyz
- !nutrition@mander.xyz
- !palaeoecology@mander.xyz
- !palaeontology@mander.xyz
- !photosynthesis@mander.xyz
- !plantid@mander.xyz
- !plants@mander.xyz
- !reptiles and amphibians@mander.xyz
Physical Sciences
- !astronomy@mander.xyz
- !chemistry@mander.xyz
- !earthscience@mander.xyz
- !geography@mander.xyz
- !geospatial@mander.xyz
- !nuclear@mander.xyz
- !physics@mander.xyz
- !quantum-computing@mander.xyz
- !spectroscopy@mander.xyz
Humanities and Social Sciences
Practical and Applied Sciences
- !exercise-and sports-science@mander.xyz
- !gardening@mander.xyz
- !self sufficiency@mander.xyz
- !soilscience@slrpnk.net
- !terrariums@mander.xyz
- !timelapse@mander.xyz
Memes
Miscellaneous
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
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.
A square matrix with the ones in the diagonal is called the identity matrix
It's an identity matrix. You multiple a vector with it and the result is still the same (identical) vector
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.
Wouldn't you need to put
anyMatrixfirst, since matrix multiplication isn't commutative?You are right. I will correct it.
No I just tried it and I was wrong, it seems like it doesn't matter for the ID matrix specifically
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.
Huh? Identity times anyMatrix is also anyMatrix. The matrix just has to have the right dimensions
Eigen see how this is confusing, I don't get it either
You multiply vectors and matrizes row by column.
So for any matrix the fitting identity matrix multiplies each row on the relevant position by one and puts it into a column.
The matrix remains the same.
See example 5 here: https://www.geeksforgeeks.org/identity-matrix/
It's like if you multiply or divide by one. Just a bit bigger cuz linear algebra.