Make Qp.integer_ring() faster. #35442
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2 tasks
|
Look good, though there are linting failures which I didn't look at. |
AFAICT, the linting failures are not my fault and fixed by #35418 . |
3 tasks
The precision for relaxed p-adics has 3 components:
`(default_prec, halting_prec, secure)`
where the last one `secure` is a boolean defaulting to `False`.
However, the `construction()` method doesn't know about it:
```
sage: K = QpER(5, secure=True)
sage: K.construction(forbid_frac_field=True)
(Completion[5, prec=(20, 40)], Rational Field)
sage: R = ZpER(5, secure=True)
sage: R.construction()
(Completion[5, prec=(20, 40)], Integer Ring)
```
This has two undesired consequences for the `change()` method:
a. The `secure` attribute is not copied:
```
sage: K.is_secure()
True
sage: K.change().is_secure()
False
sage: R.is_secure()
True
sage: R.change().is_secure()
False
```
b. The `check=False` option is broken:
```
sage: K.change(check=False)
...
ValueError: not enough values to unpack (expected 3, got 2)
sage: R.change(check=False)
...
ValueError: not enough values to unpack (expected 3, got 2)
```
Fixing the `construction()` method solves both issues.
After this commit:
```
sage: K = QpER(5, secure=True)
sage: K.construction(forbid_frac_field=True)
(Completion[5, prec=(20, 40, True)], Rational Field)
sage: K.change().is_secure()
True
sage: K.change(check=False)
5-adic Field handled with relaxed arithmetics
sage: K.change(check=False).is_secure()
True
sage: R = ZpER(5, secure=True)
sage: R.construction()
(Completion[5, prec=(20, 40, True)], Integer Ring)
sage: R.change().is_secure()
True
sage: R.change(check=False)
5-adic Ring handled with relaxed arithmetics
sage: R.change(check=False).is_secure()
True
```
The method pAdicGeneric.integer_ring() uses LocalGeneric.change() to
turn a p-adic field into a p-adic ring. The latter calls a factory
function which, by default, checks primality of p.
However, when p came from a Qp this step is not necessary. We avoid it
by adding `check=False` to the call to `LocalGeneric.change()` in
`pAdicGeneric.integer_ring()`. This results in significant time savings
for large primes, e.g. in the current test suite:
Before this commit:
```
sage: R = Qp(next_prime(10^60))
sage: timeit('R.integer_ring()')
25 loops, best of 3: 22.2 ms per loop
sage: %time TestSuite(R).run()
CPU times: user 14.4 s, sys: 44 µs, total: 14.4 s
Wall time: 14.4 s
```
After this commit:
```
sage: R = Qp(next_prime(10^60))
sage: timeit('R.integer_ring()')
625 loops, best of 3: 68 μs per loop
sage: %time TestSuite(R).run()
CPU times: user 714 ms, sys: 239 µs, total: 715 ms
Wall time: 717 ms
```
Doctest of `padic_base_leaves.py` goes down from ~33 to ~5 seconds.
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Rebased to 10.0.beta8 |
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Documentation preview for this PR is ready! 🎉 |
roed314
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Apr 7, 2023
vbraun
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Apr 23, 2023
gh-35443: Fix slow doctests or mark # long time ### 📚 Description A test is supposed to take < 1s or else be marked # long time. Here we consider slow tests taking >> 10s. When possible we fix or change the test to take less time, otherwise we just mark the test as long time. Occasionally we create a new smaller test and keep the original one as long. After this and #35442 the slowest tests are a few taking ~ 10s. The total time to doctest all goes down from 880 to 806 seconds (using `-tp 8 --all`). ~~NOTE: there's a minor merge conflict with #35314 which I will resolve once that PR is merged.~~ ### 📝 Checklist - [x] The title is concise, informative, and self-explanatory. - [x] The description explains in detail what this PR is about. URL: #35443 Reported by: Gonzalo Tornaría Reviewer(s): Gonzalo Tornaría, Matthias Köppe
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📚 Description
The method pAdicGeneric.integer_ring() uses LocalGeneric.change() to
turn a p-adic field into a p-adic ring. The latter calls a factory
function which, by default, checks primality of p.
However, when p came from a Qp this step is not necessary. We avoid it
by adding
check=Falseto the call toLocalGeneric.change()inpAdicGeneric.integer_ring(). This results in significant time savingsfor large primes, e.g. in the current test suite:
Before this commit:
After this commit:
Doctest of
padic_base_leaves.pygoes down from ~33 to ~5 seconds.Note that the
check=Falseoption for thechange()method in relaxed type is broken, so this needs #35441. Other than that this is a one-liner.📝 Checklist
⌛ Dependencies