<@U01B9FSN6Q6> concerning equality, it is not an o...
# mathematicsa
altavir
05/28/2021, 7:49 AM@Zhelenskiy concerning equality, it is not an obvious thing. First, equality should be symmetrical, it means you can't override it without thinking thirst. Also, there is a problem with performace. For example, if you take larget matrices, the content equality could be greatly time-consuming. So overriding equals could lead to improper use. For now I decided not to use equals for comparison for structures. One of the reason is that we in some cases use inline classes that lack identity.
👍 1
altavir
05/28/2021, 7:50 AMThis is also a question for @elizarov. Since it also involves the general problem of how equality of complex objects should be treated.
e
elizarov
05/28/2021, 8:13 AMI have no canned answer here. It is indeed a complex issue.
a
altavir
05/28/2021, 8:14 AMIndeed. I've decided to stop override equality because of inline classes and use exlicit methods like
Matrix.equals(m1,m2)altavir
05/28/2021, 8:15 AMBy the way, I don't remember specs, but I think it should not be present in compiler for value-classes. To avoid confusion
e
elizarov
05/28/2021, 8:18 AMIt is not currently support at all. You cannot even override equality for now. We plan to support override in the future, but figuring out the best-practices for big data-structures is a challenge. My intuition tells me that we should just learn (and teach) that big "values" are slow to compare (just like they are slow to traverse and otherwise process) with time proportional to their size, and just don't fear of having a slow
==a
altavir
05/28/2021, 8:20 AMOK. We will need to figure it out together then. Anyway, right now it is not possible to override equality for value-classes so we stick with external comparators in KMath. Otherwise it is hard to control comparison of different types (and we need the structure comparison of different types of matrices).
z
Zhelenskiy
05/28/2021, 8:24 AMMy original question was about inlining arrays in BigInt's and overridding equality there but I got a more generic answer. Thank you!
2 Views