---
title: "Magma V2.17-10 Patch Notes"
canonical: "https://docs.magma-maths.org/patchnotes/2.17-10.html"
source: "https://docs.magma-maths.org/patchnotes/2.17-10.md"
---

<a id="magma-v2-17-10-patch-notes"></a>
# Magma V2.17-10 Patch Notes

## Algebraic Function Fields

- A fix has been made to `RayResidueRing`. Reported by V. Ducet.
- `Places` of degree of a function field in relative extension representation has been improved to return large degree places over small degree places. These were previously missed.

## Basic Algebras

- A crash in [`SimpleModule`](../Algebras/BasicAlgebras/modules.md#function-simplemodule-algbas-rngintelt) for basic algebras over number fields has been fixed.  Reported by M. Towers.

## Coding Theory

- Fixed a memory leak in the minimum weight computation of codes. Reported by M. Grassl.
- Fixed an occasional crash in the intersection of a linear and an additive code.  Reported by M. Grassl.

## Coxeter Groups

- Fixed the return type of `Identity` for finitely presented Coxeter groups.

## Cyclotomic Fields

- Fixes have been made to coercion involving cyclotomic fields.
- `RootOfUnity` has been improved for large cyclotomic fields.

## Elliptic Curves

- The [`CasselsTatePairing`](../ArithmeticGeometry/EllipticCurvesOverQAndNumberFields/mordell-weil.md#function-casselstatepairing-crvhyp-crvhyp) for curves over number fields was incorrect (due to the incorrect `HilbertSymbol`).
- The [`CasselsTatePairing`](../ArithmeticGeometry/EllipticCurvesOverQAndNumberFields/mordell-weil.md#function-casselstatepairing-crvhyp-crvhyp) on $4$-coverings was incorrect for some elliptic curve that have a single rational $2$-torsion point.
- A bug in `Twists` has been corrected (in the easy case, sometimes multiple representatives of the same isomorphism class were returned).

## Finite Geometry

- A crash in the memory management of finite planes has been fixed.

## Global Arithmetic Fields

- A fix has been made to elements of global arithmetic fields. Reported by V. Ducet.
- A fix has been made to the coercion of elements involving non-simple fields. Reported by V. Ducet.

## Graphs

- A possible crash when deleting a subgraph of another graph has been fixed.  Reported by E. O’Brien.

## Groups

- A memory management problem to do with groups and their subgroups has been fixed.
- The permutation and matrix group function `Subgroups` has had an extra parameter, `IndexEqual`, added. The pc-group version of `Subgroups` already had this parameter. This brings them closer together.
- A crash computing a permutation representation of a group automorphism group has been fixed. Bug reported by D. Howden.
- The warning message about large numbers of groups from the [`SmallGroups`](../FiniteGroups/DatabasesOfGroups/smlgps-database.md#function-smallgroups-rngintelt) command is now completely disabled by setting the parameter `Warning` to false. Up till now the parameter was ignored for over 100,000 groups.

## Modular Symbols

- `IsTwist` and [`IsMinimalTwist`](../ModularArithmeticGeometry/ModularSymbols/twists.md#function-isminimaltwist-modsym-rngintelt) failed to identity twists in some cases.

## Number Fields

- Prime selection for the computation of `Subfields` has been improved. Reported by M. Grassl.
- Computation of Absolute orders has been fixed. Reported by D. Holmes.
- HilbertSymbol was incorrect (for odd primes); it has been replaced by faster code.

## Polynomials

- Exponentiation of polynomials in characteristic p has been sped up. Reported by M. Zieve.
- `I/J` and `quo`\<I|J> is now allowed when I is not the full polynomial ring.

## Quaternion Algebras

- `QuaternionicComplement` now handles algebras with non-orthogonal basis. This fixes bugs in several routines, such as isomorphism testing, for such algebras.  Reported by D. Kohel.
- `HilbertSymbol` was incorrect (for odd primes); it has been replaced by faster code.

## System

- Added the intrinsic [`GetTempDir`](../MagmaLanguage/EnvironmentAndOptions/Set-Get.md#function-gettempdir) to obtain the directory some functions are using to store files temporarily. On Unix-like systems this is the value of the environment variable `MAGMA_TEMP_DIR`, if set, and `/tmp` otherwise.