this post was submitted on 13 Jul 2023
607 points (97.3% liked)
Asklemmy
43853 readers
926 users here now
A loosely moderated place to ask open-ended questions
Search asklemmy ๐
If your post meets the following criteria, it's welcome here!
- Open-ended question
- Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
- Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
- Not ad nauseam inducing: please make sure it is a question that would be new to most members
- An actual topic of discussion
Looking for support?
Looking for a community?
- Lemmyverse: community search
- sub.rehab: maps old subreddits to fediverse options, marks official as such
- [email protected]: a community for finding communities
~Icon~ ~by~ ~@Double_[email protected]~
founded 5 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Regardless which lossless compression algorithm you prefer, it makes most files bigger.
*where "files" includes all bitstrings of a given length, whether or not they've ever existed
That's pretty disingenuous, since most files aren't just random data.
Most real files actually have rather low entropy, even if they look like random junk (e.g., executables), chiefly due to repetition of similar data and sparse values.
Exactly. It's merely our human preference for those types of files that allow them to work at all.
things get weird when we include "all possible states"
It's not a preference; it's simply the state of the system to which we may desire to apply compression.
Is it because it works on patterns and your random garbled string would have too much noise to be compressed well, while a structured file coming from an actual piece of software would probably have enough repeating patterns to the point where it actually can be shrunk?
yes. dictionary based compression is truly awful when fed random data.
the ups and downs are battling hard on the parent comment. gotta admit, I had to think for a few seconds to get the gist of it, but its actualy pretty slick and perfectly snarky.
edit: only thought would be that an infinate selection of random data sets would be somewhat evenly split between compressable and non-compressable, but if you add compression structure, it tips the balance firmly into "file size increases" territory.
very cool little comment.
*except the identity function ๐ค