Make combinat doctests ready for random seeds

[kliem]

Part of #29935.

This ticket makes

sage -t --long --random-seed=n src/sage/combinat/

pass for n more general than just 0.

See also:

• containment check for standard bracketed lyndon words does not work #30186 containment check for standard bracketed Lyndon words does not work.

Along the way we fix a tiny but annoying bug, where random derangements could fail.

That was because randint(0, n) has range range(0, n + 1),
which had caused confusion.

Depends on #29962

Component: doctest framework

Author: Jonathan Kliem

Branch: 928863f

Reviewer: Sébastien Labbé

Issue created by migration from https://trac.sagemath.org/ticket/29974

[kliem]

Branch: public/29974

[kliem]

New commits:

da1c6be	start from a "random" random seed for doctesting
b7b836d	make random seed reproducible
eedbe5e	document random_seed
998b1b9	default random seed 0 for now
1d7b00e	dash instead of underscore for command line options
e0e572e	make combinat fuzz ready
7c3a1ff	another file for combinat

[kliem]

Commit: 7c3a1ff

[kliem]

comment:2

Merge conflict.

I also need to go through it again and check I respected the design decision in #29935.

[kliem]

comment:3

Note that elements of g = GelfandTsetlinPatterns(4, 5) have the wrong parent.

[kliem]

Changed commit from 7c3a1ff to none

[kliem]

Changed branch from public/29974 to public/29974-reb

[sagetrac-git]

Commit: a914b8d

[sagetrac-git]

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

eedbe5e	document random_seed
998b1b9	default random seed 0 for now
1d7b00e	dash instead of underscore for command line options
b31e2d5	Merge branch 'public/29962' of git://trac.sagemath.org/sage into public/29962-reb
2f30dd9	small fixes
b62f781	doctests do not start from a random seed by default yet
1d99129	fix merge conflict
d40d826	make combinat fuzz ready
b9f88cf	another file for combinat
a914b8d	modify doctests according to decisions in 29935

[seblabbe]

comment:8

I get one failure in combinat:

----------------------------------------------------------------------
sage -t --long --random-seed=2 src/sage/combinat/derangements.py  # 1 doctest failed
----------------------------------------------------------------------

Can you reproduce it?

sage -t --long --random-seed=2 src/sage/combinat/derangements.py
**********************************************************************
File "src/sage/combinat/derangements.py", line 129, in sage.combinat.derangements.Derangements
Failed example:
    D2.random_element() # random
Exception raised:
    Traceback (most recent call last):
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-packages/sage/doctest/forker.py", line 715, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-packages/sage/doctest/forker.py", line 1139, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.combinat.derangements.Derangements[7]>", line 1, in <module>
        D2.random_element() # random
      File "/home/slabbe/GitBox/sage/local/lib/python3.7/site-packages/sage/combinat/derangements.py", line 504, in random_element
        return L[i]
    IndexError: list index out of range
**********************************************************************
1 item had failures:
   1 of   9 in sage.combinat.derangements.Derangements
    [85 tests, 1 failure, 0.10 s]

[kliem]

comment:9

Yes, I can confirm the problem.

[seblabbe]

Reviewer: Sébastien Labbé

[seblabbe]

comment:10

But it works for --random-seed=0, --random-seed=1, --random-seed=3, --random-seed=4.

[kliem]

Changed branch from public/29974-reb to public/29974-reb2

[kliem]

comment:11

Tiny mistake that the range of randint(0,n) is actually range(0,n+1).

---

New commits:

48bd40e	Merge branch 'public/29974-reb' of git://trac.sagemath.org/sage into test_29974
39f94e6	fix index error with random derangements

[kliem]

Changed commit from a914b8d to 39f94e6

[seblabbe]

comment:12

There is

from random import randrange

for that. Do you mind to change to the lesser known randrange?

[sagetrac-git]

Changed commit from 39f94e6 to a391a3e

[sagetrac-git]

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

a391a3e

use randrange instead of randint

[kliem]

comment:14

I like randrange much better. It is much more intuitive if you are used to range. (But reading the very short docstring that was exactly the point of introducing it.)

[seblabbe]

comment:15

In fact, I think we want to import it from prandom

from sage.misc.prandom import randrange  

in order for it to depend on the --random-seed.

[kliem]

comment:16

I was wondering about what the point was of duplicating that thing.

[sagetrac-git]

Changed commit from a391a3e to 928863f

[sagetrac-git]

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

928863f

import randrange from the correct place

[kliem]

comment:19

Thank you.

[vbraun]

Changed branch from public/29974-reb2 to 928863f

[slel]

Changed commit from 928863f to none