Fredrik Johansson's website

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Contact: fredrik.johansson@gmail.com

I'm interested in arbitrary-precision arithmetic, polynomial arithmetic, and computation of special functions. I'm the main author of mpmath and Arb, and coauthor of FLINT.

Starting in September 2014, I'm a postdoc at Inria Bordeaux-Sud-Ouest and Institut de Mathématiques de Bordeaux, working in the LFANT project-team headed by Andreas Enge and Karim Belabas.

From 2010 to 2014, I did my PhD in symbolic computation at RISC, Linz, where Manuel Kauers was my advisor. I have an MSc in engineering physics from Chalmers University of Technology, Gothenburg. I was born in Sweden.

Updates

Publications

Mathematical software

My most well-known project is probably mpmath, a Python library for arbitrary-precision floating-point arithmetic with support for complex numbers, special functions, numerical integration, linear algebra, etc. Notably, the selection of special functions may be the most extensive in any currently available open source project, comparable to Mathematica and Maple (see DLMF). The mpmath library has been cited in numerous publications. I started mpmath in 2007 and have written the majority of the code (various other people have made significant contributions).

I'm the author of Arb, a C library for asymptotically fast numerical computation with rigorous error bounds, using the concept of ball arithmetic. Arb supports complex numbers, polynomials, power series, matrices, and some special functions. I started developing Arb in 2012.

I'm a coauthor (since 2010) of FLINT, a C library for computational number theory with emphasis on asymptotically fast polynomial arithmetic. My work includes power series functions, exact linear algebra, number-theoretic special functions, and general optimizations.

In 2013, I helped develop ore_algebra, a Sage package for holonomic functions, together with Manuel Kauers and Maximilian Jaroschek. I've contributed to the Sage project since 2009, mainly by writing wrapper code for mpmath and FLINT. I attended Sage Days 15, 23, 24, 35. I also contributed extensively to the pure-Python computer algebra system SymPy from around 2007 to 2008, and designed SymPy's logo, but I'm no longer actively involved in that project.

Talks

Music

I compose MIDI music. I also have a YouTube channel with some recordings.

On the off chance that you want to know what I'm listening to at the moment, check my last.fm account.

Doom

My Doom maps and related information.