Dear Konstantin, Many thanks for reporting the bug with a detailed description. I am attaching a patch to fix it. Best wishes, Vladimir -- Vladimir V. Kisil http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Maps https://doi.org/10.1142/p835 Soft: Geometry of cycles http://moebinv.sourceforge.net/ Jupyter notebooks: https://github.com/vvkisil/MoebInv-notebooks ________________________________________ From: GiNaC-list <ginac-list-bounces@ginac.de> on behalf of Konstantin Leyde <konstantin.leyde@live.com> Sent: 22 July 2020 19:16 To: ginac-list@ginac.de Cc: vittorio del duca; Claude Duhr Subject: [GiNaC-list] Sqrfree_parfrac Issue GiNaC Hello, My name is Konstantin Leyde, and I am a master student in physics at the ETH Zurich. For my thesis project, I have been working with the GiNaC library, and I have encountered an issue with the partial fractioning (sqrfree_parfrac) routine: Unless I misunderstood the way the sqrfree_parfrac routine works, it appears that for special cases, the output of the sqrfree_parfrac routine misses a numerical prefactor for one term, and thus returns the wrong answer. Please find attached a pdf, that explains the problem in more detail. In this pdf (as well as separately) we have attached the code that shows the issue. Many thanks in advance, Best wishes, Konstantin