---
title: "Magma V2.13-12 Patch Notes"
canonical: "https://docs.magma-maths.org/patchnotes/2.13-12.html"
source: "https://docs.magma-maths.org/patchnotes/2.13-12.md"
---

<a id="magma-v2-13-12-patch-notes"></a>
# Magma V2.13-12 Patch Notes

## Algebraically Closed Fields

- A bug in coercion into a polynomial ring over an algebraically closed field has been fixed. Reported by C. Bardavid.

## Coding Theory

- A bug that caused the results of [`GriesmerMinimumWeightBound`](../CodingTheory/LinearCodes/bound.md#function-griesmerminimumweightbound-fldfin-rngintelt-rngintelt) to be too high has been fixed. Reported by M. Kiermaier.

## Elliptic Curves

- A bug when halving points on elliptic curves over fields of characteristic two has been fixed.
- The creation of elliptic curves from a hyperelliptic curve and a point should now return slightly nicer maps – an approach for characteristic 2 was accidentally being invoked for all characteristics.
- A problem in `TorsionSubgroup` for curves over function fields has been sorted out.

## Groups

- A bug in storing the subgroups of a group, giving incorrect results on a second call to `Subgroups`, has been fixed.
- A bug in `AQInvariants` applied to fp groups has been fixed. Reported by S. Humphries.

## Lattices

- Some bugs in the LLL algorithm under Windows have been fixed. Reported by T. Dokchitser.

## Matrices

- Bugs with matrix multiplication and echelonization over $GF(p^d)$ for $p\ge 256$ and $d\ge 1$ have been fixed.
- The algorithm for computing the characteristic polynomial of matrices over residue class rings has been fixed so that it does not take so much memory.

## Matrix Groups

- A problem with computing the length of a real reflection group has been fixed.

## Modular Forms

- A problem with Eisenstein series has been corrected.
- Errors with modular forms over p-adic fields, arising from relatively recent changes to p-adics, have been fixed.
- Several minor bugs have been fixed.

## Number Fields

- A bug causing internal errors when testing if two relative extensions defined by non-integral polynomials are isomorphic has been fixed.
- A bug causing internal errors in the prime splitting in relative extensions defined by non-monic polynomials has been fixed.
- A bug causing runtime-errors when computing infinite places of relative extensions over complex number fields extended by polynomials in $\matbb{Z}$ has been fixed.
- A bug in `GaloisGroup` of polynomials over number fields defined by a non-monic polynomial has been fixed.
- Calling [`AbsoluteValues`](../GlobalFields/NumberFieldsAndOrders/operation-element.md#function-absolutevalues-fldalgelt) of an element in a relative extension is now generating a runtime error rather than an internal error.
- Calling `CompleteClassGroup` (and similar functions) without a class group process being present caused internal errors. This has been changed to produce runtime errors instead.
- Calling `DecompositionType` with a negative (integer) prime now gives an error message instead of crashing.
- The minimal polynomial of the zero element of a sparse cyclotomic field of degree one no longer crashes. Reported by H. Johnston.

## Polynomial Rings

- A crash in the factorization of the polynomial 1 over function fields has been fixed. Reported by F. Hess.
- A bug in polynomial multiplication, called by arithmetic for extensions of local rings, has been fixed.
- A coercion problem in `Evaluate` has been fixed. Reported by E. Rains.

## System and Language

- Bugs in [`WriteBinary`](../MagmaLanguage/InputOutput/print.md#function-writebinary-monstgelt-bstgelt) have now been fixed.