Add C fastpath for statistics.NormalDist.inv_cdf()

[rhettinger]

BPO	37798
Nosy	@rhettinger, @taleinat, @stevendaprano, @corona10
PRs	bpo-37798: Add C fastpath for statistics.NormalDist.inv_cdf() #15266 [3.8] bpo-37798: Add C fastpath for statistics.NormalDist.inv_cdf() (GH-15266) #15441 bpo-37798: Update test_statistics.py #15453 [3.8] bpo-37798: Test both Python and C versions in test_statistics.py (GH-15453) #15467 bpo-37798: Minor code formatting and comment clean-ups #15526 [3.8] bpo-37798: Minor code formatting and comment clean-ups. (GH-15526) #15527 bpo-37798: Fix _statistics module doc #15546 [3.8] bpo-37798: Fix _statistics module doc (GH-15546) #15660 bpo-37798: Prevent undefined behavior in direct calls to the C helper… #16149 [3.8] bpo-37798: Prevent undefined behavior in direct calls to the C helper function. (GH-16149) #16160

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/rhettinger'
closed_at = <Date 2019-08-24.18:14:59.781>
created_at = <Date 2019-08-09.04:43:26.916>
labels = ['extension-modules', 'easy', '3.8', '3.9']
title = 'Add C fastpath for statistics.NormalDist.inv_cdf()'
updated_at = <Date 2019-09-15.17:04:03.394>
user = 'https://github.com/rhettinger'

bugs.python.org fields:

activity = <Date 2019-09-15.17:04:03.394>
actor = 'rhettinger'
assignee = 'rhettinger'
closed = True
closed_date = <Date 2019-08-24.18:14:59.781>
closer = 'rhettinger'
components = ['Extension Modules']
creation = <Date 2019-08-09.04:43:26.916>
creator = 'rhettinger'
dependencies = []
files = []
hgrepos = []
issue_num = 37798
keywords = ['patch', 'easy (C)']
message_count = 18.0
messages = ['349273', '349521', '349527', '350335', '350336', '350337', '350338', '350384', '350389', '350390', '350403', '350558', '350561', '350794', '351078', '351079', '352479', '352481']
nosy_count = 4.0
nosy_names = ['rhettinger', 'taleinat', 'steven.daprano', 'corona10']
pr_nums = ['15266', '15441', '15453', '15467', '15526', '15527', '15546', '15660', '16149', '16160']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue37798'
versions = ['Python 3.8', 'Python 3.9']

[rhettinger]

Create new module: Modules/_statisticsmodule.c

Add a function: _normal_dist_inv_cdf(p, mu, sigma) |-> x

Mostly, it should be a cut-and-paste from the pure Python version, just add argument processing and semi-colons.

Expect to measure a manyfold speedup.

[corona10]

@rhettinger

Hi, Can I work on this issue?
It might be my first C module addition task for CPython.

[rhettinger]

Can I work on this issue?
It might be my first C module addition task for CPython.

Yes. This issue would be a good place to start.

[rhettinger]

New changeset 0a18ee4 by Raymond Hettinger (Dong-hee Na) in branch 'master':
bpo-37798: Add C fastpath for statistics.NormalDist.inv_cdf() (GH-15266)
0a18ee4

[rhettinger]

New changeset 5779c53 by Raymond Hettinger (Miss Islington (bot)) in branch '3.8':
bpo-37798: Add C fastpath for statistics.NormalDist.inv_cdf() (GH-15266) (GH-15441)
5779c53

[rhettinger]

Thanks for doing the work one this. Nice work :-)

There's one more step. Can you please amend to the tests to run both the pure python and C versions. See Lib/test/test_heapq.py for an example of how to this.

[corona10]

There's one more step. Can you please amend to the tests to run both the
pure python and C versions.

Sure, I will take look at it!

[rhettinger]

New changeset 8ad22a4 by Raymond Hettinger (Dong-hee Na) in branch 'master':
bpo-37798: Test both Python and C versions in test_statistics.py (GH-15453)
8ad22a4

[rhettinger]

New changeset d5a66bc by Raymond Hettinger (Miss Islington (bot)) in branch '3.8':
bpo-37798: Test both Python and C versions in test_statistics.py (GH-15453) (GH-15467)
d5a66bc

[rhettinger]

Thank you again. This was nice work.

[corona10]

Thank you for the mentoring of this work.
It was great experience for me!

[rhettinger]

New changeset 6fee0f8 by Raymond Hettinger in branch 'master':
bpo-37798: Minor code formatting and comment clean-ups. (GH-15526)
6fee0f8

[rhettinger]

New changeset 56c4d2d by Raymond Hettinger (Miss Islington (bot)) in branch '3.8':
bpo-37798: Minor code formatting and comment clean-ups. (GH-15526) (GH-15527)
56c4d2d

[corona10]

@rhettinger
If you are okay, Can you review PR 15546, please?
IMHO, this issue should be fixed ASAP...
Thanks again

[taleinat]

New changeset 0cf832a by Tal Einat (Dong-hee Na) in branch 'master':
bpo-37798: Fix _statistics module doc (GH-15546)
0cf832a

[taleinat]

New changeset 58067d2 by Tal Einat (Miss Islington (bot)) in branch '3.8':
bpo-37798: Fix _statistics module doc (GH-15546)
58067d2

[rhettinger]

New changeset 6e27a0d by Raymond Hettinger in branch 'master':
bpo-37798: Prevent undefined behavior in direct calls to the C helper function. (bpo-16149)
6e27a0d

[rhettinger]

New changeset d6fdfc8 by Raymond Hettinger (Miss Islington (bot)) in branch '3.8':
bpo-37798: Prevent undefined behavior in direct calls to the C helper function. (GH-16149) (GH-16160)
d6fdfc8