--- title: "Magma V2.27-5 Patch Notes" canonical: "https://docs.magma-maths.org/patchnotes/2.27-5.html" source: "https://docs.magma-maths.org/patchnotes/2.27-5.md" --- # Magma V2.27-5 Patch Notes ## Coding Theory - Some spurious printing in `IsIsomorphic` for codes has been fixed. Reported by A. Munemasa. ## Complex Field - A hang in polynomial root finding over the complex field in a case where multiple complex roots had very small imaginary part (arising from computations in hyperelliptic curves) has been fixed. Reported by J. Voight. ## Curves - A failure in [`EightDescent`](../ArithmeticGeometry/EllipticCurvesOverQAndNumberFields/mordell-weil.md#function-eightdescent-crv) for a certain class of curves has been fixed. Reported by R. Rathbun. ## Elliptic Curves - A crash in `TwoDescent` for elliptic curves has been fixed. Reported by R. Rathbun. - The [`SelmerGroup`](../ArithmeticGeometry/EllipticCurvesOverQAndNumberFields/mordell-weil.md#function-selmergroup-map) algorithm has been improved so that it runs much faster on certain types of input. Example problem reported by J. Rouse. ## Finite Fields - For a finite field extension with the Zech representation but a non-primitive defining polynomial, the internal generator of the Zech-based field was not chosen uniquely; this been changed so sorting involving elements of such a field now always behaves the same, irrespective of the random seed. Issue reported by C. Rito. ## Local Rings - $p$-adic rings constructed as a `Completion` of the integers were unintentionally returned as fields. Reported by E. Assaf. ## Polynomial Rings - A bad slowdown in resultant computation for some types of multivariate polynomials has been fixed. Reported by N. Katz. ## System - Some crashes in the save/restore feature running under Mac OS X have been fixed. Reported by T. Uchiyama. - The AVX2/CUDA version is now built for CUDA version 11.x so please upgrade your system(s) to CUDA 11 if you have been using the CUDA version 10.x Magma executable.