Make learnerND datastructures immutable where possible

[basnijholt]

(original issue on GitLab)

opened by Joseph Weston (@jbweston) at 2018-07-10T13:16:25.518Z

At the moment there are a few datastructures that are described as "sets". where possible we should make these frozenset to remove the possibility of them being modified.

[basnijholt]

originally posted by Jorn Hoofwijk (@Jorn) at 2018-07-13T11:46:10.397Z on GitLab

Wauw, according to this thread , a frozenset is hashable and can therefore be used as a dictionary key. Maybe this is a clean way to store simplices (rather than having a sorted tuple) in the triangulation/learner.

any opinions?

[basnijholt]

originally posted by Joseph Weston (@jbweston) at 2018-07-13T11:49:40.261Z on GitLab

In [1]: import sys

In [2]: sys.getsizeof((1, 2, 3))
Out[2]: 72

In [3]: sys.getsizeof(frozenset((1, 2, 3)))
Out[3]: 224

just saying

[basnijholt]

originally posted by Jorn Hoofwijk (@Jorn) at 2018-07-13T11:50:33.059Z on GitLab

ohw, that is a shame

[basnijholt]

originally posted by Joseph Weston (@jbweston) at 2018-07-13T11:50:41.004Z on GitLab

because a frozenset is a hashmap, whereas a tuple is an array

[basnijholt]

originally posted by Bas Nijholt (@basnijholt) at 2018-12-07T20:00:10.457Z on GitLab

Will this ever be implemented? If not, can we close it?

[basnijholt]

originally posted by Anton Akhmerov (@anton-akhmerov) at 2018-12-07T20:10:46.447Z on GitLab

It's ~"priority: low", so please let's not close it. @jbweston's illustration shows clearly that there's a clear benefit in implementing this issue.

[basnijholt]

originally posted by Joseph Weston (@jbweston) at 2018-12-08T09:53:44.558Z on GitLab

@jbweston's illustration shows clearly that there's a clear benefit in implementing this issue.

No, I was just saying that we should prefer tuples over sets where possible, but that some of the structures that currently are sets should be frozenset if they can be

[basnijholt]

originally posted by Anton Akhmerov (@anton-akhmerov) at 2018-12-08T20:25:06.809Z on GitLab

Indeed, I misunderstood.

Looking at the documentation of LearnerND I'm not sure what data structures would benefit from conversion.

On the other hand, it does seem like we could make a bunch of methods private and therefore make the API simpler.

[basnijholt]

originally posted by Bas Nijholt (@basnijholt) at 2018-12-11T11:56:04.313Z on GitLab

Like this @anton-akhmerov? https://gitlab.kwant-project.org/qt/adaptive/merge_requests/142