Misc improvements to integer.pyx

[sagetrac-spancratz]

Generic code clean-up such as line breaks, empty lines, use of GMP functions etc

Before:

sage: x = factorial(2**14)
sage: timeit('y = odd_part(x)')
625 loops, best of 3: 10.6 µs per loop

sage: odd_part(0)
---------------------------------------------------------------------------
...
TypeError: unsupported operands for >>: 0, +Infinity

After:

sage: x = factorial(2**14)
sage: timeit('y = x.odd_part()')
625 loops, best of 3: 4.52 µs per loop

sage: ZZ(0).odd_part()
0

Apply attachment: trac_10596.patch, attachment: trac_10596_remove_trailing_whitespaces.patch

CC: @sagetrac-jthurber @zimmermann6

Component: basic arithmetic

Author: Sebastian Pancratz, André Apitzsch

Reviewer: Aly Deines, John Cremona

Merged: sage-5.0.beta0

Issue created by migration from https://trac.sagemath.org/ticket/10596

[sagetrac-spancratz]

Attachment: trac-10596.patch.gz

[sagetrac-jthurber]

comment:5

I had the following failures to apply, 4.6.1.rc1 on OS X.
This doesn't have 5945 as a prerequisite, does it?

22:14:56johnthurber~/sage/sage-4.6.1.rc1/devel/sage$ hg qpush
applying trac-10596.patch
patching file sage/rings/integer.pyx
Hunk #10 FAILED at 1268
Hunk #37 succeeded at 3276 with fuzz 1 (offset -106 lines).
Hunk #42 FAILED at 3577
Hunk #58 succeeded at 4302 with fuzz 1 (offset -106 lines).
Hunk #62 succeeded at 4643 with fuzz 2 (offset -106 lines).
Hunk #73 FAILED at 5289
3 out of 82 hunks FAILED -- saving rejects to file sage/rings/integer.pyx.rej
patch failed, unable to continue (try -v)
patch failed, rejects left in working dir
errors during apply, please fix and refresh trac-10596.patch

[adeines]

comment:6

I had the same thing happen as well.

[adeines]

Reviewer: Aly Deines

[sagetrac-spancratz]

comment:8

I'm sorry, I think this is because I was working on this with 4.6.0 rather than 4.6.1.rc0. I will fix that this morning. Sebastian

[sagetrac-spancratz]

Attachment: trac-10596-461rc0.patch.gz

Version for 4.6.1.rc0

[adeines]

comment:9

All tests pass for me.

There's some of code I don't understand . . . so I'm not giving this a positive review.

[a-andre]

comment:10

integer.pyx: ndigits(): unsigned long b is never used. (rc0 patch version)

[loefflerd]

comment:11

Hi Sebastian,

Hope you're well. Trivial comment: it's the done thing to put full names, not trac usernames, in the Author and Reviewer fields because they're used for compiling the release notes.

Less trivial: can you perhaps do a micro-patch that gets rid of the unused variable in ndigits? The rest of the code looks fine to me, and it would be good to get this positively reviewed soon, because any patch that changes quite so many lines of code is going to be highly vulnerable to bitrotting (it already conflicts with my patch at #10625, sigh).

Regards, David

[loefflerd]

Changed author from spancratz to Sebastian Pancratz

[mstreng]

comment:12

Replying to @loefflerd:

it would be good to get this positively reviewed soon, because any patch that changes quite so many lines of code is going to be highly vulnerable to bitrotting

Bitrotting happened: failed to apply trac-10596-461rc0.patch on sage-4.6.2.alpha4

[a-andre]

comment:13

Rebased the patch by spancratz and added a patch that removes some trailing whitespaces.

Apply trac_10596_remove_trailing_whitespaces.patch after trac_10596.patch

[a-andre]

Attachment: trac_10596.patch.gz

Attachment: trac_10596_remove_trailing_whitespaces.patch.gz

[a-andre]

comment:16

I removed the ndigits() part because problem was fixed in #11796.

[JohnCremona]

comment:17

The patches apply cleanly to 4.8.alpha4: but there are quite a few warning on rebuilding, about variables being referenced before assignment. Does this matter?

[JohnCremona]

comment:18

Replying to @JohnCremona:

The patches apply cleanly to 4.8.alpha4: but there are quite a few warning on rebuilding, about variables being referenced before assignment. Does this matter?

All tests pass and docbuild is clean. I would give a positive review were it not for those warnings. If someone knows that they are not serious, please tell me.

[JohnCremona]

Changed reviewer from Aly Deines to Aly Deines, John Cremona

[JohnCremona]

comment:19

Replying to @JohnCremona:

Replying to @JohnCremona:

The patches apply cleanly to 4.8.alpha4: but there are quite a few warning on rebuilding, about variables being referenced before assignment. Does this matter?

All tests pass and docbuild is clean. I would give a positive review were it not for those warnings. If someone knows that they are not serious, please tell me.

The warnings seem not to be caused by this patch at since when I popped the patch and rebuilt they came up again. So, do they matter?

[a-andre]

comment:20

Warnings are caused by lines like

cdef mpz_t tmp
mpz_init(tmp)

This seems to be a Cython problem, see http://trac.cython.org/cython_trac/ticket/714 and http://mail.python.org/pipermail/cython-devel/2011-September/001437.html, so warnings shouldn't matter.

[a-andre]

comment:21

See also #11761 comment:17.

[mstreng]

comment:22

Replying to @JohnCremona:

I would give a positive review were it not for those warnings.

And #11761 shows that the warnings are ok.

[a-andre]

Changed author from Sebastian Pancratz to Sebastian Pancratz, André Apitzsch

[jdemeyer]

Merged: sage-5.0.beta0

[loefflerd]

comment:26

Apply trac_10596.patch, trac_10596_remove_trailing_whitespaces.patch

(for the patchbot, so it understands the prerequisites for building #12116 against Sage 4.8)