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Integer and Rational classes need nth_root and exact_power functions #8

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sagetrac-dmharvey mannequin opened this issue Sep 12, 2006 · 1 comment
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Integer and Rational classes need nth_root and exact_power functions #8

sagetrac-dmharvey mannequin opened this issue Sep 12, 2006 · 1 comment
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c: basic arithmetic p: major / 3 t: enhancement

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@sagetrac-dmharvey
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sagetrac-dmharvey mannequin commented Sep 12, 2006

It would be useful for Integer and Rational classes to have:

(1) nth_root: this would wrap GMP's mpz_root.
(2) exact_power: would accept a rational number as an index, and work out which root to take. For example

(-8/27).exact_power(2/3) == 4/9

I had to take an exact 6th root of a rational in some code the other day and it was painful going via real numbers, worrying about bits of precision and all that.

Component: basic arithmetic

Issue created by migration from https://trac.sagemath.org/ticket/8
@sagetrac-dmharvey
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sagetrac-dmharvey mannequin commented Sep 16, 2006

comment:1

Fixed.

Fri Sep 15 17:19:10 PDT 2006 dmharvey@math.harvard.edu

  • Rational.nth_root() -- adds Rational nth root method

Fri Sep 15 17:18:20 PDT 2006 dmharvey@math.harvard.edu

  • Integer.nth_root() -- adds nth root method to Integer (wraps GMP mpz_root)

@sagetrac-dmharvey sagetrac-dmharvey mannequin closed this as completed Sep 16, 2006
@jpflori jpflori mentioned this issue Jan 20, 2011
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vbraun pushed a commit that referenced this issue Mar 26, 2023
gh-35114: libgap: Remove some GC hazards
0d01c38 
    
### 📚 Description

Trac branch `u/gh-collares/gap-gc` from #34701, now migrated to GitHub.
Currently based atop #35093; will rebase once that is merged.

The rest of the description below is copied from #34701:

A refactor in #27946 introduced "unprotected" (not surrounded by
`GAP_Enter`/`GAP_Leave`) `GAP_ValueGlobalVariable` calls. I believe this
might be a GC hazard, because after updating to GAP 4.12.1 I started
seeing aarch64 crashes on NixOS infrastructure such as:

```
#0  0x0000fffff79740e8 in wait4 ()
#1  0x0000fffff5dc6b78 in print_enhanced_backtrace ()
#2  0x0000fffff5dc8190 in sigdie ()
#3  0x0000fffff5dcb1c0 in cysigs_signal_handler ()
#4  0x0000fffff7ffb7cc in __kernel_rt_sigreturn ()
#5  0x0000ffff99a0bf28 in ConvString ()
#6  0x0000000000000000 in ?? ()
#7  0x0000000000000000 in ?? ()
#8  0x0000000000000000 in ?? ()
#9  0x0000ffff99989930 in Pr ()
#10 0x0000ffff9998aa18 in CloseOutput ()
#11 0x0000ffff99884828 in capture_stdout () at /build/sage-
src-9.7/pkgs/sagemath-standard/sage/libs/gap/element.pyx:154
...
```
I also see cases where `capture_stdout` throws errors such as
`sage.libs.gap.util.GAPError: Error, Length: <list> must be a list (not
the integer 255)` and then crashes. Both types of errors are fixed by
this ticket.

Note that I am nesting `GAP_Enter`/`GAP_Leave` calls because I didn't
remove the preexisting calls inside `capture_stdout`. That's because I
feared removing the innermost calls might create a new footgun (and I
believe nested `GAP_Enter`/`GAP_Leave` calls are explicitly supported),
but removing them should cause no problem. Removing them might even be
preferable for performance reasons, I don't know.

Fixes #34701

### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. -->
<!-- If your change requires a documentation PR, please link it
appropriately -->
<!-- If you're unsure about any of these, don't hesitate to ask. We're
here to help! -->

- [x] I have made sure that the title is self-explanatory and the
description concisely explains the PR.
- [x] I have linked an issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation accordingly.

### ⌛ Dependencies
<!-- List all open pull requests that this PR logically depends on -->
<!--
- #xyz: short description why this is a dependency
- #abc: ...
-->
- #35093: GAP 4.12.2 upgrade, which touches the same function and should
land first.
    
URL: #35114
Reported by: Mauricio Collares
Reviewer(s): Dima Pasechnik
vbraun pushed a commit that referenced this issue Jun 3, 2023
@soehms
sync_labels_actor_authorized initial (#8)
aa449ef
jsantillan3 added a commit to jsantillan3/sage that referenced this issue Jul 28, 2023
@jsantillan3
Add examples to OneSumNode in seymour_decomposition.pyx, add methods …
9df7a19 
…block_matrix_form, summand_matrices (sagemath#8)

* wip onesum

* wip onesum2

* wip onesum test

* onesum node example

* fixed names of .summand_matrices() and .block_matrix_form,
....: and added examples to ._children()

* style fixes

---------

Co-authored-by: J S <javier@javiers-mbp.mynetworksettings.com>
Co-authored-by: J S <javier@campus-017-091.ucdavis.edu>
vbraun pushed a commit that referenced this issue Oct 8, 2023
@Aaron-Dwyer
Merge pull request #8 from Aaron-Dwyer/coveringarray
379a7bb 
fixed another typo
xuluze pushed a commit to xuluze/sage that referenced this issue Dec 12, 2023
@jsantillan3 @mkoeppe
Add examples to OneSumNode in seymour_decomposition.pyx, add methods …
e6bcca9 
…block_matrix_form, summand_matrices (sagemath#8)

* wip onesum

* wip onesum2

* wip onesum test

* onesum node example

* fixed names of .summand_matrices() and .block_matrix_form,
....: and added examples to ._children()

* style fixes

---------

Co-authored-by: J S <javier@javiers-mbp.mynetworksettings.com>
Co-authored-by: J S <javier@campus-017-091.ucdavis.edu>
xuluze pushed a commit to xuluze/sage that referenced this issue Feb 23, 2024
@jsantillan3 @mkoeppe
Add examples to OneSumNode in seymour_decomposition.pyx, add methods …
d5ac816 
…block_matrix_form, summand_matrices (sagemath#8)

* wip onesum

* wip onesum2

* wip onesum test

* onesum node example

* fixed names of .summand_matrices() and .block_matrix_form,
....: and added examples to ._children()

* style fixes

---------

Co-authored-by: J S <javier@javiers-mbp.mynetworksettings.com>
Co-authored-by: J S <javier@campus-017-091.ucdavis.edu>
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