Fredrik Johansson's website

General information

I have a blog, updated sporadically. I also have a GitHub account.

I'm a PhD student in the Algorithmic Combinatorics group at RISC. My home page at RISC contains some more information.

Efficient implementation of the Hardy-Ramanujan-Rademacher formula (preprint, 2011): Presents new record computations of the partition function p(n). Some congruence data is available.
A fast algorithm for reversion of power series (preprint, 2011): Describes an algorithm for reversion (compositional inverse) of power series. This algorithm is usually faster than other methods in practice.

mpmath: A Python library for arbitrary-precision floating-point arithmetic with extensive support (similar to Mathematica and Maple) for high-precision numerical approximation of special functions, integrals, series, etc. Main author, started in 2007.
FLINT: A fast C library for computational number theory. I have worked on power series arithmetic, linear algebra and special functions, among other features. I have a page with some benchmarks. Coauthor, joined 2010.
Sage: A project to create a free/open source alternative to Magma, Maple, Mathematica and Matlab. My main contribution has been to integrate mpmath and write Cython extension code to make mpmath faster. Contributor since 2009.
SymPy: A Python library for symbolic computations. I've worked on various modules (special functions, number theory, statistics, physics...) as well as core symbolics and arithmetic (mpmath began its life as a SymPy module). Contributor since 2007, no longer actively involved.

My Doom maps and related information.