No, it’s an n-tuple with certain algebraic properties.
Comment on Explain yourselves, comp sci.
SpaceNoodle@lemmy.world 1 year ago
It’s a dynamically-sized list of objects of the same type stored contiguously in memory.
Leate_Wonceslace@lemmy.dbzer0.com 1 year ago
KidnappedByKitties@lemm.ee 1 year ago
This is such an understated but useful description in this context. It’s also how I understood algebra for applied matrix computation.
Leate_Wonceslace@lemmy.dbzer0.com 1 year ago
I was just coming down from THC when I wrote this, so I’m extra jazzed you liked it. 😁
GnomeKat@lemmy.blahaj.zone 1 year ago
Its the algebraic properties that are important, not all vectors are n-tuples, eg the set of polynomials of degree less than n.
You need a basis to coordinate a vector, you can work with vectors without doing that and just deal with the algebraic properties. The coordinate representation is dependent on the basis chosen and isn’t fundamental to the vector. So calling them n-tuples isn’t technically correct.
You can turn them into a set of coordinates if you have a basis, but the fact that you can do that is because of the algebraic properties so it’s those properties which define what a vector is.
Leate_Wonceslace@lemmy.dbzer0.com 1 year ago
I think a better example to show how vectors don’t necessarily need to be what people conceptualize as n-tuples would have been the real numbers. (Of course, these can be considered 1-tuples, but the same can be said of any arbitrary set element that is not itself a tuple with more entries.) A cooler example would have been R[x] (the ring of real-valued polynomials of a single variable) especially since an isomorphic ring using n-tuples would be a more cumbersome representation of the algebra.
conquer4@lemmy.world 1 year ago
So an ArrayList?
joyjoy@lemm.ee 1 year ago
No. ArrayList is thread safe and implements the connections API. Vector doesn’t. Though if you’re using Java, there’s almost no instance where you would want to use a Vector instead of ArrayList.
DaPorkchop_@lemmy.ml 1 year ago
ArrayList isn’t thread-safe, though…
joyjoy@lemm.ee 1 year ago
Thread safe as in it raises an exception instead of breaking your list.
fossilesque@mander.xyz 1 year ago
Image
ipha@lemm.ee 1 year ago
It’s like a fancy list.
fossilesque@mander.xyz 1 year ago
So is a wedding gift registry.
whereBeWaldo@lemmy.dbzer0.com 1 year ago
No this is Patrick!
Fosheze@lemmy.world 1 year ago
dynamically-sized: The size of it can change as needed.
list: It stores multiple things together.
object: A bit of programmer defined data with.
of the same type: all the objects in the list are the same kind of object
stored contigiously in memory: if you think of memory as a bookshelf then all the objects on the list would be stored right next to each other on the bookshelf rather than spread across the bookshelf.
kbotc@lemmy.world 1 year ago
Dynamically sized but stored contiguously makes the systems performance engineer in me weep. If the lists get big, the kernel is going to do so much churn.
Killing_Spark@feddit.de 1 year ago
Contiguous storage is very fast in terms of iteration though often offsetting the cost of allocation
IAmVeraGoodAtThis@lemmy.blahaj.zone 1 year ago
Which is why you should:
Vec
doubles in size every time it runs out of space)yetiftw@lemmy.world 1 year ago
matlab likes to pick the smallest available spot in memory to store a list, so for loops that increase the size of a matrix it’s recommended to preallocate the space using a matrix full of zeros!
tamal3@lemmy.world 1 year ago
Is that churn or chum? (RN or M)
SpaceNoodle@lemmy.world 1 year ago
Many things like each other lined up in a row, and you can take some away or put more in.
mindbleach@sh.itjust.works 1 year ago
It’s how you want an array to work.