Action for Bundle Connections

[mjungmath]

In this ticket, we establish the action of a bundle connection. We implement the component-wise formula based on the connection form.

See Wikipedia for details.

Depends on #30208
Depends on #30228

CC: @egourgoulhon @tscrim

Component: manifolds

Author: Michael Jung

Branch/Commit: 7ae2df9

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/30209

[mjungmath]

Branch: u/gh-mjungmath/bundle_connection_change_of_frame

[mjungmath]

Last 10 new commits:

f0c6ee8	Trac #30191: minor fix
f1221da	Trac #30191: minor fix
a042313	Trac# 30191: wrong indentation reverted
4cc92e9	Trac #30191: comp check unified to if comp
f98a47b	Trac #30191: unused ScalarField import removed
9c5a25b	Trac #30208: assigment for bundle connections
fa87f4b	Trac #30208: documentation improved
b7a6a5f	Merge branch 'develop' into bundle_connection_change_of_frame
0c28d89	Trac #30209: forms from scratch
56996fd	Trac #30209: bundle connection action

[mjungmath]

Commit: 56996fd

[mjungmath]

Changed dependencies from #30208 to #30208, #30228

[mjungmath]

Changed dependencies from #30208, #30228 to #30208, #30228, #30239

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. Last 10 new commits:

ef8ac4b	Trac #30209: display method + merge
51ba4e3	Trac #30239: comp zero check for __call__
bd1f299	Trac #30209: Merge branch 't/30239/tensorfield___call___alters_zero' into bundle_connection_change_of_frame
e7fedb7	Trac #30209: display method finished
b03baa1	Trac #30209: structure formula fixed
bb476e2	Trac #30208: minor fix
a77aebc	Trac #30208: copy_from reverted to recover old behavior
934a439	documentation slightly improved
574445d	Trac #30209: Merge branch 'bundle_connection_extension' into bundle_connection_change_of_frame
0e3cba0	Trac #30209: documentation finished + display only_nonzero fixed

[sagetrac-git]

Changed commit from 56996fd to 0e3cba0

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

2dd78aa

Trac #30209: documentation improved

[sagetrac-git]

Changed commit from 0e3cba0 to 2dd78aa

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

e5a3ac4

Trac #30209: documentation imrpoved

[sagetrac-git]

Changed commit from 2dd78aa to e5a3ac4

[mjungmath]

comment:10

I don't think the depencency of #30239 is necessary anymore. Anyway, I'll leave it this way. Removing it again would be too complicated by now...

[mjungmath]

comment:11

The pycodestyle error has been fixed in #30239.

[sagetrac-git]

Changed commit from e5a3ac4 to 933c14a

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. Last 10 new commits:

504e84e	Trac #30239: Merge branch 't/30266/immutability_for_scalar_fields' into t/30239/tensorfield___call___alters_zero
d58d291	Trac #30266: hash function condition + treatment of restrictions
061b89f	Trac #30266: minor doctest improvement
5c7fd6e	Trac #30266: immutability of restrictions + hash function improved
7ba0865	Trac #30266: merge
0ec99d4	Trac #30266: check by name
87fb411	Trac #30266: ValueError replaced by AssertionError
43ec497	Trac #30239: referenced before assignment error fixed
135ffd5	Trac #30209: Merge branch 't/30239/tensorfield___call___alters_zero' into bundle_connection_change_of_frame
933c14a	Trac #30209: Merge branch 'develop' into bundle_connection_change_of_frame

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

d3c8cab	Trac #30208: random doctest removed
5cee80c	Trac #30209: Merge branch 'bundle_connection_extension' into bundle_connection_action
21f2bd5	Trac #30209: bundle connections acting on sections + vector fields

[sagetrac-git]

Changed commit from 933c14a to 21f2bd5

[mjungmath]

comment:14

I have removed the dependency of #30239.

[mjungmath]

Changed dependencies from #30208, #30228, #30239 to #30208, #30228

[mjungmath]

comment:15

Green patchbot.

[tscrim]

comment:16

I don't like doctests marked as random that are not random:

sage: nab.connection_forms() # random

Just go through the different values and get the output explicitly (and maybe check the len). This will be more robust and actually catch errors.

Your error messages in display don't need to be so excited (just remove the ! from the end).

While it is good to keep encapsulation, just be aware that changes like this:

-                    rk = vb._rank
+                    rk = vb.rank()

mean extra Python function calls, which are relatively expensive compared to attribute lookup. However, I have no objections to these changes as they seem like they would not have any significant impact on computation times.

[mjungmath]

comment:17

Replying to @tscrim:

I don't like doctests marked as random that are not random:

sage: nab.connection_forms() # random

Just go through the different values and get the output explicitly (and maybe check the len). This will be more robust and actually catch errors.

Ah, you already mentioned that in some ticket. Sure, I will take care of that.

Your error messages in display don't need to be so excited (just remove the ! from the end).

:(

While it is good to keep encapsulation, just be aware that changes like this:

-                    rk = vb._rank
+                    rk = vb.rank()

mean extra Python function calls, which are relatively expensive compared to attribute lookup. However, I have no objections to these changes as they seem like they would not have any significant impact on computation times.

Ah, this is good to know! I'll change it back.

Tomorrow...

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

ec05c7f	Trac #30209: Merge branch 't/30208/d3c8cab917f04ebc9951d41a0cc8dcf4c66392a6' into new_bundle_connection_action
7ae2df9	Trac #30209: action of bundle connections + display method

[sagetrac-git]

Changed commit from 21f2bd5 to 7ae2df9

[mjungmath]

comment:19

I see. Something went wrong during the rebase. Please double check in comparison with #30208.

[mjungmath]

comment:20

I've forced a new push btw. Like I said, please take a thorough look.

[mjungmath]

comment:21

Compared with #30208 once again. Looks good, like intended. Patchbot is green again.

[tscrim]

Reviewer: Travis Scrimshaw

[tscrim]

comment:22

Thank you. LGTM.

[mjungmath]

comment:23

Thank you for the review.

[vbraun]

Changed branch from u/gh-mjungmath/bundle_connection_change_of_frame to 7ae2df9